Liquid crystal display device

Abstract

To provide, in a semiconductor device including a holding capacitor with a light-transmitting property including a semiconductor film with a light-transmitting property, a conductive film, and an insulating film, a driving method for stably operating the holding capacitor.SOLUTION: A display device includes a pixel including an enhancement transistor, a pixel electrode to which a predetermined potential is supplied from a signal line through the transistor, and a holding capacitor having the pixel electrode functioning as one electrode, electrically connected to a capacitor line, and including a semiconductor film with a light-transmitting property that functions as the other electrode. The potential in which the potential difference between the pixel electrode and the capacitor line becomes higher than a threshold voltage of the holding capacitor is supplied to the capacitor line.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The invention disclosed in this specification and the like relates to a semiconductor device and a method for driving the semiconductor device.

Background Art

[0002] In recent years, flat panel displays such as liquid crystal displays (LCDs) have become widely popular. In a display device such as a liquid crystal display, a transistor as a switching element, a liquid crystal element electrically connected to the transistor, and a holding capacitor connected in parallel with the liquid crystal element are provided in pixels arranged in the row direction and the column direction. As a semiconductor material constituting the semiconductor film included in the transistor, silicon semiconductors such as amorphous (non-crystalline) silicon or poly (polycrystalline) silicon are widely used.

[0003]

[0004]

[0005] <00​​​​​​​​​​​​​​​​​​This allows for a longer period during which the orientation can be kept constant, thereby reducing the power consumption of the display device. This can be hoped for.

[0007] For example, to increase the charge capacity of the retaining capacitance, the occupied area of ​​the retaining capacitance is increased. Specifically, one method is to increase the area over which the pair of electrodes overlap. However, Furthermore, in the above-mentioned display device, in order to increase the area over which the pair of electrodes overlap, light shielding properties are used. Increasing the area of ​​the conductive film reduces the aperture ratio of the pixels, which degrades the display quality of the image. .

[0008] Therefore, a translucent storage capacity formed using a translucent material is used as a display device. A technology is disclosed that enables an increase in charge capacity without reducing the aperture ratio by providing it in this manner. (See Patent Document 3). [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2007-123861 [Patent Document 2] Japanese Patent Publication No. 2007-96055 [Patent Document 3] U.S. Patent No. 8102476 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The holding capacity of the display device disclosed in Patent Document 3 is determined by a light-transmitting semiconductor having one electrode. A body membrane is used, and a light-transmitting conductive film (specifically, a pixel electrode) is used for the other electrode, and a dielectric The film uses a light-transmitting insulating film. Furthermore, one of the electrodes included in the holding capacity... Thin film transistors are included in display devices and are switching elements. A channel layer provided on the gate insulating layer of a Transistor (TFT) (specifically) It is formed of an oxide semiconductor. And the oxide semiconductor used as one of the electrodes The conductor is an electron-density-increased oxide that can be used in depletion-type TFTs. It is a material semiconductor. The other electrode uses a pixel electrode. In Patent Document 3, one of the electrodes The potential difference between the common potential applied to the capacitance line connected to the electrode and the pixel potential applied to the pixel electrode. The holding capacitor is operated with the voltage range set to around 0V.

[0011] As shown in Patent Document 3, one of the electrodes of the holding capacitance is made of an oxide semiconductor with increased electron density. In that case, considering the method of manufacturing the display device, it is included in the display device and as a switching element. A functioning TFT can be a depletion-type TFT. Depletion-type transistors When a transistor is used as a switching element, the threshold voltage of the transistor is lower than 0V. It is a high voltage.

[0012] Furthermore, generally speaking, in a display device, the video data potential supplied to the display element is common electric. The potential used is within the potential amplitude centered on the position, and the common potential is often set to 0V. .

[0013] As described above, using a depletion-type TFT as the switching element as in Patent Document 3 A display device having a retention capacity formed using an oxide semiconductor contained in the TFT is Because the voltage range required to drive the display device is wider, power consumption has increased. It will serve as a display device. Furthermore, in order to make the TFT function as a switching element, the TFT will always The need to supply voltage to it also leads to increased power consumption of the display device.

[0014] Therefore, one aspect of the present invention relates to a light-transmitting semiconductor film, a light-transmitting conductive film, and A semiconductor device having a light-transmitting retention capacitance and composed of an insulating film having properties, One of the objectives is to provide a semiconductor device with reduced power consumption.

[0015] Furthermore, the holding capacity described in Patent Document 3 is such that during its operation, the other electrode is permeable A positive bias is constantly applied to the photosensitive conductive film. Therefore, the retained capacitance The threshold voltage fluctuates in the positive direction over time. Therefore, the voltage range in which the retaining capacitor operates is... If the threshold voltage is near 0V, the retaining capacitor may not operate due to changes in the threshold voltage over time. It is possible.

[0016] Therefore, in a holding capacitance using an oxide semiconductor as one of the electrodes, the operating range is expanded. This is significant.

[0017] Therefore, one aspect of the present invention relates to a light-transmitting semiconductor film, a light-transmitting conductive film, and A semiconductor device having a light-transmitting retention capacitance and composed of an insulating film having properties, One of the objectives is to provide a driving method for stably operating the said holding capacity.

[0018] Furthermore, one aspect of the present invention relates to a semicircular structure capable of stably operating a light-transmitting holding capacity. One of the objectives is to provide a conductive device. [Means for solving the problem]

[0019] In view of the above problems, one aspect of the present invention relates to an enhancement-type transistor and a transistor A retaining capacitor electrically connected to the resistor, a capacitance line electrically connected to the retaining capacitor, and a transistor It comprises an indicator and a holding capacitor and an electrically connected display element, and the holding capacitor has a capacitance line and A translucent semiconductor film that is electrically connected and functions as one electrode, and the other electrode It functions as a transparent conductive film contained in the display element, and one electrode and the other electrode It has a dielectric film placed between them, and the threshold voltage is 0V or higher, and the retaining capacitance is The potential difference between a translucent conductive film and a capacitance line causes the translucent semiconductor film to become conductive. This is a semiconductor device characterized by operating on a potential difference.

[0020] Furthermore, one aspect of the present invention relates to an enhancement-type transistor and an electric transistor and electricity A retaining capacitor that is electrically connected to the retaining capacitor, a capacitance line electrically connected to the retaining capacitor, and a transistor and It comprises a holding capacitor and an electrically connected display element, the holding capacitor being electrically connected to a capacitance line. Therefore, a translucent semiconductor film functions as one electrode, and the other electrode functions as the other electrode. A light-transmitting conductive film included in the display element and provided between one electrode and the other electrode. A dielectric film is provided, and the threshold voltage is 0V or higher, and the retaining capacitance is transparent. The potential difference between the conductive film and the capacitance line operates at a potential difference greater than the threshold voltage of the retained capacitance. This semiconductor device is characterized by the following features.

[0021] The retaining capacitance can be formed by utilizing the transistor formation process. A translucent semiconductor film that functions as one of the electrodes is a semiconductor included in a transistor. It can be formed using a film formation process. In other words, as one of the electrodes of the holding capacity... A translucent semiconductor film capable of light transmission is made on the same surface as the translucent semiconductor film of the transistor. It is formed in such a way. Oxide semiconductor films are used for the light-transmitting semiconductor films of transistors. Transistors using oxide semiconductor films formed with appropriate processing can be enhanced. It is a sment-type transistor. Furthermore, this transistor has an extremely low off-current. Therefore, the power consumption of semiconductor devices can be reduced.

[0022] Furthermore, in the following, the light transmission properties of the semiconductor film and retention capacitance contained in the transistor are described. The semiconductor film possessed shall be described as an oxide semiconductor film.

[0023] In the above, the oxide semiconductor film having retention capacitance, and the oxide semiconductor film having transistor The conductive film has an equivalent carrier density. And the oxide semiconductor film having retention capacitance, A process that involves adding impurities that increase conductivity in order to intentionally increase carrier density. This is an oxide semiconductor film that has not undergone any processing.

[0024] A semiconductor device according to one aspect of the present invention, which includes a transistor that functions as a switching element. This is an enhancement-type transistor having an oxide semiconductor film, and one of the retained capacitances The oxide semiconductor film that constitutes the enhancement-type transistor is formed on the electrode simultaneously. By using an oxide semiconductor film, a semiconductor using a depletion-type transistor is created. Compared to other devices, it is possible to narrow the voltage range for driving semiconductor devices, and semiconductor devices This can reduce the power consumption of the device.

[0025] Furthermore, the dielectric film for retaining capacitance is provided on the oxide semiconductor film included in the transistor. An insulating film can be applied, and it is a transparent conductive material that functions as the other electrode of the holding capacitance. The film is included in the display element and is applied to the pixel electrodes that are electrically connected to the transistor. can.

[0026] In this way, the retaining capacitance is transparent, so in the pixel, the transistor It can be formed on a large scale (over a large area) in regions other than where it is formed. Therefore, this development In one aspect, it is possible to obtain a semiconductor device that increases both the aperture ratio and the charge capacitance. It is possible. Furthermore, by improving the aperture ratio, it is possible to obtain semiconductor devices with superior display quality. can.

[0027] Furthermore, one aspect of the present invention includes not only the semiconductor device described above, but also a method for driving the semiconductor device. Born.

[0028] One aspect of the present invention is an enhancement-type transistor and a signal transmitted through the transistor. A pixel electrode is supplied with a predetermined potential from a line, and the pixel electrode functions as one of the electrodes, and the capacitance line A retainer having a translucent semiconductor film that is electrically connected to the other electrode and functions as the other electrode. A method for driving a display device having pixels having capacitance, wherein the gate electrode of a transistor A potential greater than the transistor's threshold voltage is supplied to the scan line having the transistor, thereby leading the transistor. The system is set to a pass-through state, a predetermined potential is supplied to the pixel electrode from the signal line, and a light-transmitting semiconductor is connected to the capacitance line. By supplying a potential that causes the potential difference between the body membrane and the capacitance line to be higher than the threshold voltage of the retained capacitance, retention is achieved. The capacitance is characterized by maintaining a potential difference between the potential of the pixel electrode and the potential of the capacitance line for a certain period of time. This is a method for driving semiconductor devices.

[0029] Furthermore, one aspect of the present invention involves an enhancement-type transistor and a transistor via A pixel electrode to which a predetermined potential is supplied from the signal line, and the pixel electrode functions as one of the electrodes, It has a capacitance line and a translucent semiconductor film that is electrically connected to it and functions as the other electrode. A method for driving a display device having a pixel having a holding capacity, wherein the gate of a transistor A potential greater than the threshold voltage of the transistor is supplied to the scanning line having the electrode. The terminal is made conductive, a predetermined potential is supplied to the pixel electrode from the signal line, and the capacitance line is supplied to the pixel electrode. By supplying a potential that is lower than the predetermined potential supplied by the threshold voltage of the retaining capacitance, the retaining capacitance The semicircular electrode is characterized by maintaining the potential difference between the potential of the pixel electrode and the potential of the capacitance line for a certain period of time. This is a method for driving a conductive device.

[0030] The above driving method provides a translucent semiconductor film, a translucent conductive film, and translucency To extend the operating range of the retention capacity of a semiconductor device having a retention capacity with an insulating film having an insulating film. This allows for stable operation of the holding capacity.

[0031] In this specification, the threshold voltage of the retaining capacitance is defined as the threshold voltage of a translucent semiconductor film. It is assumed that a so-called MOS capacitance is formed by the elementary electrodes and the insulating film placed between them. At that point, a storage layer is formed on the translucent semiconductor film, and the charge capacitance begins to increase at a certain voltage. It refers to. [Effects of the Invention]

[0032] A semiconductor film having light-transmitting properties, a conductive film having light-transmitting properties, and an insulating film having light-transmitting properties. This invention provides a method for stably operating a retaining capacitance in a semiconductor device equipped with such a capacitance. It is possible to have a high aperture ratio and a large charge capacity. This technology can provide a semiconductor device that has high capacity and reduced power consumption. [Brief explanation of the drawing]

[0033] [Figure 1] A diagram showing a semiconductor device, and a circuit diagram of a pixel. [Figure 2] A diagram showing the Id-Vg curve, CV curve of the retained capacitance, and potentials of the pixel electrodes and capacitance lines of a transistor included in a semiconductor device. [Figure 3] A diagram illustrating the operation method of the retaining capacitance included in a semiconductor device. [Figure 4] A top view showing the pixels of a semiconductor device. [Figure 5] A cross-sectional view showing the pixels of a semiconductor device. [Figure 6] A cross-sectional view showing a method for fabricating pixels in a semiconductor device. [Figure 7] A cross-sectional view showing a method for fabricating pixels in a semiconductor device. [Figure 8] A top view showing the pixels of a semiconductor device. [Figure 9] A cross-sectional view showing the pixels of a semiconductor device. [Figure 10] A cross-sectional view showing the pixels of a semiconductor device. [Figure 11] A top view showing the pixels of a semiconductor device. [Figure 12] A cross-sectional view showing the pixels of a semiconductor device. [Figure 13] A top view showing the pixels of a semiconductor device. [Figure 14] A cross-sectional view showing the pixels of a semiconductor device. [Figure 15] A top view showing the pixels of a semiconductor device. [Figure 16] A top view showing the pixels of a semiconductor device. [Figure 17] A cross-sectional view showing a transistor that can be applied to the pixels of a semiconductor device. [Figure 18] A top view showing a semiconductor device. [Figure 19] Cross-sectional view showing a semiconductor device. [Figure 20] Cross-sectional view showing a semiconductor device. [Figure 21] A top view and a cross-sectional view showing a portion of the scanning line drive circuit of a semiconductor device. [Figure 22] A top view and a cross-sectional view showing the common connection part of a semiconductor device. [Figure 23] A diagram showing an electronic device using a semiconductor device. [Figure 24] A diagram showing an electronic device using a semiconductor device. [Modes for carrying out the invention]

[0034] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention The following description is not limited to the fact that its form and details can be changed in various ways, as any person skilled in the art would know. This is easily understood. Furthermore, the present invention shall be interpreted as being limited to the contents of the embodiments described below. It's not something that can be done.

[0035] In the configuration of the present invention described below, the same part or part having a similar function The same symbols are used consistently across different drawings, and explanations of their repetition are omitted. When referring to a part that has a function, the hatch pattern is the same, and no special symbol is assigned. be.

[0036] In each figure described herein, the size of each component, the thickness of the film, or the area are for clarity. Therefore, it may be exaggerated. Thus, it is not necessarily limited to that scale.

[0037] In this specification, the ordinal numbers used, such as "1st," "2nd," etc., are for convenience only. This does not indicate the order of processes or the order of lamination. Furthermore, the invention is not specified in this specification. This does not indicate a specific name for the purpose of providing a particular information.

[0038] Furthermore, the functions of "source" and "drain" in this invention are related to the operation of the circuit. The order may change if the direction changes, etc. Therefore, in this specification, The terms "source" and "drain" may be used interchangeably.

[0039] Furthermore, voltage refers to the potential difference between two points, while electric potential refers to the electrostatic field at a given point. This refers to the electrostatic energy (electrical potential energy) possessed by a unit charge within a given object. Furthermore, generally speaking, the potential difference between the potential at a certain point and a reference potential (for example, the ground potential) This is simply called electric potential or voltage, and the terms electric potential and voltage are often used as synonyms. Therefore, unless otherwise specified in this specification, potential may be read as voltage. You may substitute "voltage" with "potential."

[0040] In this specification, when etching is performed after photolithography: The mask formed by photolithography shall be removed.

[0041] (Embodiment 1) In this embodiment, a semiconductor device and a method for driving a semiconductor device, which are aspects of the present invention, are described below. This will be explained using the drawings. In this embodiment, a semiconductor device which is one aspect of the present invention will be used. This will be described as a liquid crystal display device.

[0042] <Configuration of a semiconductor device> Figure 1(A) shows an example of the configuration of a semiconductor device. The semiconductor device shown in Figure 1(A) is The pixel section 100, the scan line driving circuit 104, and the signal line driving circuit 106 are each parallel or approximately m scan lines 10 are arranged in parallel and their potential is controlled by the scan line drive circuit 104. 7 and each is arranged in parallel or approximately parallel, and the potential is controlled by the signal line drive circuit 106. It has n signal lines 109 that are used. Furthermore, the pixel section 100 is arranged in a matrix. It has multiple pixels 101 arranged in parallel or approximately parallel to each other along the scan line 107. It has capacity lines 115 installed. The capacity lines 115 run along the signal lines 109, They may be arranged in parallel or approximately parallel.

[0043] Each scan line 107 is one of the pixels 101 arranged in m rows and n columns in the pixel section 100. It is electrically connected to n pixels 101 arranged in any row. Also, each signal line 109 This refers to m pixels 101 arranged in m rows and n columns, where m pixels 10 are located in any of the columns. It is electrically connected to 1. m and n are both integers greater than or equal to 1. Also, each capacitance line 115 This refers to n pixels 101 located in any row among the m rows and n columns of pixels 101. It is electrically connected to 1. Note that the capacitance line 115 is parallel to the signal line 109, and each is parallel to the other. If they are arranged in roughly parallel directions, then any of the pixels 101 arranged in m rows and n columns The m pixels 101 arranged in a row are electrically connected.

[0044] Figure 1(B) is an example of a circuit diagram of pixel 101 in the semiconductor device shown in Figure 1(A). The pixel 101 shown in Figure 1(B) is electrically connected to the scan line 107 and the signal line 109. The transistor 103 is electrically connected to a capacitance line 115, one of which supplies a constant potential. The other electrode is electrically connected to the drain electrode of transistor 103, and the retaining capacitor 1 05 and the pixel electrode 121 are the drain electrode of transistor 103 and the other of retaining capacitance 105. The electrodes are electrically connected to the electrodes, and the electrodes (counter electrodes) are provided opposite the pixel electrodes 121. It has a liquid crystal element 108 that is electrically connected to a wiring that supplies a potential shift.

[0045] Transistor 103 is an enhancement-type transistor. Therefore, the threshold When the value voltage is 0V or higher, that is, when the gate voltage (Vg) is 0V or higher, the on-current (d A current (Id) flows, and transistor 103 becomes conductive (see Figure 2(A)). In other words, when no gate voltage is applied, no on-current flows, so transistor 103 Compared to using a depletion-type transistor, the power consumption of the semiconductor device is reduced. It can be reduced. In this specification, gate voltage refers to the voltage between the gate electrode and the source voltage. This refers to the potential difference between the poles.

[0046] Furthermore, an oxide semiconductor film treated under appropriate conditions is applied to the channel formation region of the transistor. When used, the off-current of the transistor can be drastically reduced. Transistor 103 Since the channel formation region uses an oxide semiconductor film 111 treated under appropriate conditions, Transistor 103 is a transistor with an extremely low off-current. Therefore, this One aspect of the invention is a semiconductor device that has reduced power consumption.

[0047] Furthermore, transistors using oxide semiconductors with increased carrier density are depressurized This becomes a 1-type transistor. On the other hand, transistor 103 is an enhancement-type transistor. The oxide semiconductor film 111 contained in transistor 103 is a transistor, and the carrier density is To increase the conductivity graphically, treatments such as adding impurities that increase conductivity are not performed. It is an oxide semiconductor film.

[0048] The holding capacity 105 has a dielectric film provided between the pair of electrodes and is transparent. One electrode of the holding capacity 105 is an oxide semiconductor film 119, and the dielectric film is transient A light-transmitting insulating film provided on the oxide semiconductor film 111 contained in the star 103. The other electrode is the pixel electrode 121. Therefore, the retaining capacitance 105 is transistor 1 It can be formed using the formation process of 03. Control the potential applied to the pixel electrode 121. By making the oxide semiconductor film 119 conductive, the oxide semiconductor film 119 becomes one of the electrodes. It functions as follows. Therefore, the retention capacity 105 is MOS (Metal Oxide Sem). It can be said that it has an iconductor (capacitor) structure.

[0049] Furthermore, the oxide semiconductor film 119 with a retention capacity of 105 is an enhancement-type transistor. The oxide semiconductor film 111 included in the transistor 103 is formed using the formation process. Therefore, the retaining capacitance 105, like the transistor 103, has a capacitance line with the pixel electrode 121. Charging begins when the potential difference with 115 is 0V or higher. In other words, the holding capacity of 105 The voltage value is 0V or higher.

[0050] Figure 2(B) shows the CV curve for a holding capacity of 10⁵. In Figure 2(B), the horizontal axis represents the holding capacity. This graph shows the potential difference (VP-VC) between the pixel electrode 121 and the capacitance line 115 of 105, with the vertical axis representing the current electrical potential difference. This represents capacitance (C) relative to the positional difference. Note that CV measurement (Capacitance-Vo The voltage frequency during (weight-measurement) is around the frame frequency of the semiconductor device. When the wavenumber is smaller than the CV curve, the CV curve is as shown in Figure 2(B).

[0051] In this specification, the potential difference between the pixel electrode 121 and the capacitance line 115 is defined as the potential difference between the pixel electrode 12 This is the value obtained by subtracting the potential of capacitance line 115 (VC) from the potential of point 1 (VP) (see Figure 2(C)). Note that Figure 2(C) shows transistor 103 and retaining capacitor 105 for clarity. They are doing it.

[0052] Furthermore, the oxide semiconductor film 119 with a retention capacity of 105 contains oxides contained in the transistor 103. Since it can be formed using the process of forming a physical semiconductor film 111, the carrier density can be intentionally increased. These oxides have not undergone any treatment such as adding impurities to increase conductivity in order to increase their conductivity. It is a semiconductor film. The carrier density of the oxide semiconductor film 119 is the same as that of the oxide semiconductor film 111. It is equivalent to the rear density.

[0053] From the above, the oxide semiconductor film 119 with a retention capacity of 105 and the acid contained in the transistor 103 Since the semiconductor film 111 has the same configuration, the threshold voltage (Vth) of the retaining capacitance 105 This is equivalent to the threshold voltage (Vth_Tr) of transistor 103 (Figures 2(A) and 2(A) and 2(A)). 2(B)).

[0054] The liquid crystal element 108 is formed on a substrate on which the transistor 103 and the pixel electrode 121 are formed, and opposite The optical modulation effect of the liquid crystal sandwiched between the substrate on which the electrodes are formed causes light transmission or opacity. It is an element that controls overflow. Furthermore, the optical modulation effect of liquid crystals is due to the electric field applied to the liquid crystal (in the vertical direction). It is controlled by an electric field (including an electric field in an oblique direction). Note that the base on which the pixel electrodes are formed When a counter electrode (also called a common electrode) is formed on a plate, the electric field applied to the liquid crystal is lateral This results in a field in the direction of the electric field.

[0055] The scan line drive circuit 104 and the signal line drive circuit 106 consist of a logic circuit section and a switch section or a It is broadly divided into the fa section and the detailed configuration of the scan line drive circuit 104 and the signal line drive circuit 106. Although I will omit the details, the scan line drive circuit 104 and the signal line drive circuit 106 have transistors It contains "ta".

[0056] Furthermore, the traces included in one or both of the scan line drive circuit 104 and the signal line drive circuit 106 The transistor can be formed using the formation process of transistor 103. In other words, One or both of the scan line drive circuit 104 and the signal line drive circuit 106 are connected to transistor 103 and It can be provided on the substrate on which the pixel electrode 121 is provided. In this way, the scanning line driving circuit By integrally forming one or both of 104 and the signal line drive circuit 106 on the substrate, the semiconductor The number of parts in the device can be reduced, thereby lowering manufacturing costs.

[0057] Furthermore, the trajectory included in one or both of the scan line drive circuit 104 and the signal line drive circuit 106 The generator is used to ensure that the scan line drive circuit 104 and the signal line drive circuit 106 operate correctly. Furthermore, it is preferable to use an enhancement-type transistor rather than a depletion-type transistor. This also suggests that transistor 103 should be an enhancement-type transistor. This is significant.

[0058] From the above, since the holding capacity 105 is light-transmitting, the transistor 103 of the pixel 101 It can be formed on a large scale (over a large area) in areas other than where it is formed. Therefore, in Figure 1 The semiconductor device shown is one in which the aperture ratio is increased while the charge capacitance is increased. , a semiconductor device with excellent display quality. For example, in a semiconductor device according to one aspect of the present invention And, the pixel density should be 300 ppi (pixels per inch) or more (for example, 300pp If the pixel aperture is set to approximately i-330ppi, the pixel aperture ratio should be 50% or more, and furthermore, the pixel aperture ratio Furthermore, the aperture ratio of the pixels can be increased to 55% or more, and even to 60% or more. One embodiment is a semiconductor device in which the aperture ratio of pixels is higher than that of conventional semiconductor devices.

[0059] Here, a method for driving a semiconductor device, which is one aspect of the present invention, will be described. The semiconductor device has a MOS capacitor structure with a holding capacitance of 105, In order for the holding capacity 105 to operate stably, one of the electrodes of the holding capacity 105 must function as... The potential applied to the oxide semiconductor film 119 (in other words, the capacitance line 115) is as follows.

[0060] The CV curve for a holding capacitance of 105 is shown in Figure 2(B) when the threshold voltage is 0V or higher. This is a CV curve. During the period in which the holding capacity 105 is operated, the holding capacity 105 is moved stably. To enable this, the storage capacity 105 must be fully charged. For example, during the period The potential difference (VP) between the potential of the pixel electrode 121 with a holding capacitance 105 and the potential of the capacitance line 115. Apply a potential VC to the capacitance line 115 such that -VC) is between V1 and V2 in Figure 2(B). (See Figures 2(B) and 2(C)).

[0061] Furthermore, during the period in which the retention capacitor 105 is in operation, the potential of the pixel electrode 121 is the signal line 1 It has positive and negative amplitudes depending on the signal input to 09. Specifically, Therefore, it fluctuates in the positive and negative directions relative to the center potential of the video signal. In order to keep the potential difference (VP-VC) between V1 and V2 during that period, the capacitance line The potential (VC) of 115 (oxide semiconductor film 119) is maintained from the low potential of the pixel electrode 121. The potential should be lowered by at least the threshold voltage of quantity 105 (see Figure 3). Of the potentials supplied to scan line 107, the lowest potential is defined as GVss, and the highest potential is defined as GVss. Let the position be GVdd.

[0062] In other words, in order to operate the holding capacity 105, During this period, the potential difference between the pixel electrode 121 and the capacitance line 115 (oxide semiconductor film 119) The voltage should be higher than the threshold voltage of the holding capacitance of 105.

[0063] Furthermore, the threshold voltage of the retaining capacitance 105 is equivalent to the threshold voltage of the transistor 103. Therefore, the potential of the capacitance line 115 (oxide semiconductor film 119) is determined by the transistor 103. It is sufficient to lower the voltage by more than the value of 1. By doing so, the retaining capacitor 105 will operate. During this period, the oxide semiconductor film 119 can be kept in a conductive state at all times, and the holding capacity The quantity 105 can be kept stable and operated.

[0064] From the above, by using a driving method according to one aspect of the present invention, a light-transmitting semiconductor film can be obtained. A semiconductor device having a light-transmitting conductive film and a light-transmitting insulating film, and a retention capacity. In this configuration, the holding capacity can be stabilized over time and operated accordingly.

[0065] Furthermore, transistor 103 is an enhancement-type transistor, and its retention capacitance is 10 Using the formation process of transistor 103, which is an enhancement-type transistor, 5 To form. For this reason, in a semiconductor device according to one aspect of the present invention, to drive the retained capacitance The voltage range required for this purpose is obtained by applying a depletion-type transistor, and The carrier density was increased by utilizing the depletion-type transistor formation process. This voltage range is narrower than the voltage range required to drive the retention capacitance formed using an oxide semiconductor film. Therefore, by adopting one aspect of the present invention, the power consumption of the semiconductor device can be reduced. .

[0066] <Upper surface structure and cross-sectional structure of a semiconductor device> Next, we will explain the specific structure of the semiconductor device. Here, we will use pixel 101 as an example. To clarify, Figure 4 shows a top view of pixel 101. Note that Figure 4 is a half view for clarity. Some components of the conductive device (for example, liquid crystal element 108) have been omitted.

[0067] In Figure 4, scan line 107 extends in a direction approximately perpendicular to signal line 109 (left-right direction in the figure). It is provided in an extended manner. The signal line 109 is in a direction approximately perpendicular to the scan line 107 (up and down in the figure). The capacity line 115 is provided extending in the direction parallel to the scan line 107. The scan line 107 and capacitance line 115 are connected to the scan line drive circuit 104 (Figure 1 (A The signal line 109 is electrically connected to the signal line drive circuit 106 (see Figure 1( A) See reference) and it is electrically connected.

[0068] Transistor 103 is located in the region where scan line 107 and signal line 109 intersect. The transistor 103 has at least an oxide semiconductor film 11 having a channel-forming region. 1, gate electrode, gate insulating film (not shown in Figure 4), source electrode, drain electrode Includes poles.

[0069] Furthermore, scan line 107 includes a region that functions as the gate electrode of transistor 103, Line 109 includes a region that functions as the source electrode of transistor 103. Conductive film 113 This includes a region that functions as the drain electrode of transistor 103, through the aperture 117. It is electrically connected to the pixel electrode 121. Note that in Figure 4, the pixel electrode 121 is The diagram omits the "ching" part.

[0070] The region that functions as a gate electrode is at least an oxide semiconductor film 1 in scan line 107. This is the region that overlaps with 11. The region that functions as the source electrode is small in signal line 109. This is a region that overlaps with the oxide semiconductor film 111, even if it is not present. This region functions as a drain electrode. This is a region in the conductive film 113 that overlaps with at least the oxide semiconductor film 111. In the following, the scan line 107 is also used to refer to the gate electrode of transistor 103. In some cases, it may be included, and when pointing to the source electrode of transistor 103, the signal line 109 and It may be noted. The conductive film 11 is also used when referring to the drain electrode of transistor 103. Write 3.

[0071] Furthermore, in the top surface shape, the end of scan line 107 is located outside the edge of the semiconductor film. Therefore, the scan line 107 functions as a light-shielding film that blocks light from light sources such as backlights. As a result, the oxide semiconductor film 111 contained in the transistor is not irradiated with light, and the transistor This can suppress fluctuations in the electrical characteristics of the station.

[0072] The holding capacity 105 is located in the region enclosed by the scan line 107 and the signal line 109. The retention capacity 105 consists of an oxide semiconductor film 119, a light-transmitting pixel electrode 121, and a dielectric As a body film, a translucent insulating film (not shown in Figure 4) is formed on the transistor 103. It consists of an oxide semiconductor film 119, a light-transmitting pixel electrode 121, and Since both dielectric films are translucent, the retention capacity 105 is translucent. The oxide semiconductor film 119 communicates with capacitance lines 115 through the conductive film 125 provided in the opening 123. Because they are in contact, the holding capacitance 105 is electrically connected to the capacitance line 115.

[0073] The retained capacitance changes depending on the area over which the pair of electrodes overlap. Reducing the pixel size to increase resolution also reduces the amount of storage space required. As a result, the charge capacity that can be stored decreases. It may not be possible. Since the retention capacity 105 is light-transmitting, it is necessary to maximize the amount of data within the pixel. It is possible to form a large-area retention capacity, and the liquid crystal element 108 operates within a certain range. A total holding capacitance can be formed. A charge that can fully operate the liquid crystal element. As long as sufficient capacity is available, the pixel density can be increased and the resolution can be raised.

[0074] Here, we will describe the characteristics of transistors using oxide semiconductors. The transistor used is an n-channel transistor. Furthermore, it is contained in oxide semiconductors. Oxygen deficiency can lead to the generation of carriers, affecting the electrical characteristics and reliability of transistors. This could potentially degrade performance. For example, changing the threshold voltage of a transistor in the negative direction. Furthermore, drain current can flow when the gate voltage is 0V. The phenomenon where drain current flows when the power voltage is 0V is called the normally-on characteristic. Furthermore, when the gate voltage is 0V, it can be assumed that no drain current is flowing. The characteristic of the converter is called the normally-off characteristic.

[0075] Therefore, when using oxide semiconductor films, defects contained in the oxide semiconductor film, typically oxygen It is preferable that defects be minimized as much as possible. For example, the direction of the magnetic field is parallel to the film surface. The spin density with a g value of 1.93 obtained by electron spin resonance applied to the row (contained in the oxide semiconductor film) This corresponds to the defect density.) It is preferable that this is reduced to below the detection limit of the measuring instrument. It is difficult. By reducing defects in oxide semiconductor films, typically oxygen vacancies, as much as possible. This can suppress the transistor from exhibiting normally-on characteristics, and the electrical characteristics of the semiconductor device This can improve aerodynamic characteristics and reliability.

[0076] The negative fluctuation in the transistor threshold voltage is not only due to oxygen deficiency, but also to oxides. This can also be caused by hydrogen (including hydrogen compounds such as water) contained in semiconductor films. There is a hydrogen contained in the oxide semiconductor film that reacts with the oxygen bonded to the metal atom to form water. In both cases, there is a defect (or oxygen deficiency) in the lattice where oxygen has been removed (or in the region where oxygen has been removed). It forms a hydrogen atom. In addition, some of the hydrogen reacts with oxygen to generate electrons, which are carriers. Therefore, transistors having an oxide semiconductor film containing hydrogen are normally... It tends to exhibit ON characteristics.

[0077] From the above, hydrogen is formed in the oxide semiconductor film 111 contained in transistor 103. It is preferable that it be reduced as much as possible. Specifically, in the oxide semiconductor film 111, secondary The hydrogen concentration obtained by secondary ion mass spectrometry (SIMS) is less than 5 × 10 atoms / cm , 3 , , 18 atoms / cm 3 , preferably or less than 1 × 10 18 atoms / cm 3 or less, more preferably less than 5 × 10 17 atoms / c m 3 or less, still more preferably less than 1 × 10 16 atoms / cm 3 or less.

[0078] In addition, for the oxide semiconductor film 111, the concentration of alkali metal or alkaline earth metal obtained by secondary ion mass spectrometry is 1 × 10 18 atoms / cm 3 or less, preferably 2 × 1 0 16 atoms / cm 3 or less. Alkali metals and alkaline earth metals may generate carriers when combined with the oxide semiconductor, which may increase the off-current of the transistor 103. When nitrogen is contained in the oxide semiconductor film 111, carriers in the form of electrons are generated, increasing the carrier density and making it prone to n-type formation. As a result, a transistor having an oxide semiconductor film containing nitrogen tends to have normally-on characteristics. Therefore, in the oxide semiconductor film 111, it is preferable that nitrogen is reduced as much as possible. For example, the nitrogen concentration is preferably 5 × or less.

[0079] In addition, when the oxide semiconductor contains group 14 elements such as silicon and carbon, carriers are generated, and the carrier density increases, making it prone to n-type formation. As a result, a transistor having an oxide semiconductor film containing nitrogen tends to have normally-on characteristics. Therefore, in the oxide semiconductor film 111, it is preferable that nitrogen is reduced as much as possible. For example, the nitrogen concentration is preferably 5 × or less. In addition, when the oxide semiconductor contains group 14 elements such as silicon and carbon, carriers 10 18 atoms / cm<​​​​​​Electrons are generated, increasing the carrier density and making it easier to convert to n-type. Therefore, the oxide semiconductor film In a transistor having, in particular, the gate insulating film 127 (not shown in Figure 4) and the acid At the interface of the silicon semiconductor film 111, the silicon concentration obtained by secondary ion mass spectrometry is 3 x 10 18 atoms / cm 3 The following is preferably 3 × 10 17 atoms / cm 3 The following applies. Furthermore, the carbon concentration obtained at the interface by secondary ion mass spectrometry is , 3 x 10 18 atoms / cm 3 The following is preferably 3 × 10 17 atoms / cm 3 Below It will be below.

[0081] From the above, impurities (hydrogen, nitrogen, silicon, carbon, alkali metals or alkaline earth metals) By reducing (etc.) as much as possible and using a highly purified oxide semiconductor film 111, This suppresses the normally-on characteristics of transistor 103, and the The current can be reduced to an extremely low level. Therefore, one aspect of the present invention has good electrical characteristics. It is a semiconductor device that is highly reliable. A semiconductor can be described as an intrinsic or substantially intrinsic semiconductor.

[0082] Furthermore, transistor 103 is an enhancement-type transistor, and is made of oxide semiconductor material. Film 111 is intentionally modified to increase its carrier density by adding impurities that increase conductivity. Since the oxide semiconductor film has not undergone any processing, the oxide semiconductor film 111 The carrier density is 1 × 10⁻⁶ 17 / cm 3 The following, or 1 × 1016 / cm 3 Below, again is 1 x 10 15 / cm 3 The following, or 1 × 10 14 / cm 3 The following, or 1 × 10 13 / cm 3 The following applies:

[0083] Furthermore, the oxide semiconductor film 119 contained in the retention capacity 105 is included in the transistor 103. Since it can be formed using the process of forming an oxide semiconductor film 111, the oxide semiconductor film 1 Since the carrier density of 19 is equivalent to that of the oxide semiconductor film 111, acid The carrier density of the ionized semiconductor film 119 is within the above range.

[0084] Furthermore, the low off-current of transistors using highly purified oxide semiconductor films indicates that This can be proven through various experiments. For example, if the channel width is 1 × 10⁻⁶ 6 Channel length L in μm Even if the element is 10 μm, the voltage between the source electrode and the drain electrode (drain voltage) is 1 In the range from V to 10V, the off-current is below the measurement limit of the semiconductor parameter analyzer. That is, 1 × 10 -13 The characteristic of being less than or equal to A can be obtained. In this case, the transient The off-current, which corresponds to the value obtained by dividing by the channel width, must be 100 Hz A / μm or less. I understand. Also, by connecting the retaining capacitor and the transistor, current flows into or out of the retaining capacitor. The off-current was measured using a circuit that controls the outflowing charge with the transistor in question. In this measurement, a highly purified oxide semiconductor film is used in the channel formation region of the transistor. The off-current of the transistor is measured from the change in the amount of charge per unit time of the retained capacitance. As a result, when the voltage between the source and drain electrodes of the transistor is 3V, tens of It was found that an even lower off-current of yA / μm could be obtained. Therefore, high purity Transistors using oxide semiconductor films exhibit remarkably low off-current.

[0085] Next, Figure 5 shows cross-sectional views between the dashed lines A1-A2 and B1-B2 in Figure 4. .

[0086] The cross-sectional structure between the dashed lines A1-A2 and B1-B2 is as follows: Substrate On 102, there is a scan line 107 that includes a region that functions as a gate electrode, and a capacitance line 115, A gate insulating film 127 is provided on the scan line 107 and the capacitance line 115. The oxide semiconductor film 111 is provided on the region of the gate insulating film 127 that overlaps with the scan line 107. An oxide semiconductor film 119 is provided on the gate insulating film 127. A signal including a region on the conductive film 111 and on the gate insulating film 127 that functions as a source electrode. A wire 109 and a conductive film 113 including a region that functions as a drain electrode are provided. A portion of the gate insulating film 127 that is in contact with the capacitance line 115 has an opening 1 that reaches the capacitance line 115. 23 is provided, and on the opening 123, gate insulating film 127 and oxide semiconductor film 119 A conductive film 125 is provided. On the gate insulating film 127, on the signal line 109, an oxide semiconductor Transients are placed on film 111, conductive film 113, conductive film 125, and oxide semiconductor film 119. Insulating films 129, 131, and 132 function as protective insulating films for sta 103. A conductive film 113 is provided in insulating film 129, insulating film 131, and insulating film 132. An opening 117 is provided to reach the opening 117 and the insulating film 132, and a pixel electrode 121 A feature is provided. In addition, an alignment film 158 is provided on the pixel electrode 121 and the insulating film 132. Furthermore, the substrate 102, the scan lines 107 and capacitance lines 115, and the gate insulating film 127 are A base insulating film may be provided between them.

[0087] Furthermore, the cross-sectional structure of the liquid crystal element 108 is as follows: Substrate 150 facing substrate 102. A light-shielding film 152 is provided in at least the region of the surface that overlaps with the transistor 103. Furthermore, a light-transmitting conductive film, which is a counter electrode 154, is provided so as to cover the light-shielding film 152. The pixel electrode 121 and insulating film 156 are provided so as to cover the opposing electrode. An alignment film 158 is provided on the film 132. The insulating film 132 and pixel electrode on the substrate 102 side. An alignment layer 158 is provided on 121. The liquid crystal 160 consists of an alignment layer 156 and an alignment layer 158 It is provided in contact with the substrate and is sandwiched between substrates 102 and 150.

[0088] Furthermore, when the semiconductor device according to one aspect of the present invention is a liquid crystal display device, the backlight, etc. The light source, and optical components such as polarizing plates provided on the substrate 102 side and the substrate 150 side, respectively (light A substrate (academic board), sealing material to fix substrate 102 and substrate 150, etc. are required, but these This will be explained later.

[0089] As described above, in the holding capacity 105 shown in this embodiment, one of the pair of electrodes The first electrode is an oxide semiconductor film 119, and the second electrode of the pair is a pixel electrode 121. The dielectric films provided between the pair of electrodes are insulating film 129, insulating film 131, and insulating film 132 That is the case.

[0090] The components of the above cross-sectional structure are described in detail below.

[0091] There are no major restrictions on the material of the substrate 102, but at least in the semiconductor device manufacturing process... It must have sufficient heat resistance to withstand the heat treatment performed on it. For example, a glass substrate. These include ceramic substrates and plastic substrates, and as for glass substrates, barium veneer Alkaline-free glass such as aluminoborosilicate glass, aluminoborosilicate glass, or aluminosilicate glass. A glass substrate is preferable. Alternatively, a substrate that does not transmit light, such as a stainless steel alloy, can be used. It is also possible to have it. In that case, it is preferable to provide an insulating film on the substrate surface. 102 refers to a quartz substrate, a sapphire substrate, or a single-crystal semiconductor substrate, a polycrystalline semiconductor substrate, and Using composite semiconductor substrates, SOI (Silicon On Insulator) substrates, etc. It is also possible to use a transmissive liquid crystal display device as the semiconductor device in one aspect of the present invention. In this case, the substrate 102 is a light-transmitting substrate.

[0092] The scanning lines 107 and capacitance lines 115 are preferably formed of a metal film because they carry large currents. Typical examples include molybdenum (Mo), titanium (Ti), tungsten (W), and tantalum. Ta), aluminum (Al), copper (Cu), chromium (Cr), neodymium (Nd), sucrose A single-layer structure using metallic materials such as sodium (Sc) or alloy materials with these as the main components. Alternatively, it may be provided in a laminated structure.

[0093] An example of a scanning line 107 and a capacitance line 115 is one using silicon-containing aluminum. Single-layer structure, double-layer structure with titanium laminated on aluminum, titanium laminated on titanium nitride A two-layer structure, a two-layer structure in which tungsten is laminated on titanium nitride, tantalum nitride with Two-layer structure with stacked stainless steel, two-layer structure with stacked copper on a copper-magnesium-aluminum alloy. Structure, such as a three-layer structure in which copper is layered on titanium nitride and then tungsten is formed on top of that. There is.

[0094] Furthermore, as the material for the scanning line 107 and capacitance line 115, a light-transmitting material applicable to the pixel electrode 121 is also used. A conductive material having certain properties can be used. Furthermore, a semiconductor device according to one aspect of the present invention When using a reflective display device, the pixel electrode 121 is made of a conductive material that does not transmit light (for example) (If metal material is used) can be used. In that case, the substrate 102 is also a substrate that does not have light transmission. It can be used.

[0095] Furthermore, as the material for the scanning line 107 and the capacitance line 115, a nitrogen-containing metal oxide, specifically This includes nitrogen-containing In-Ga-Zn oxides, nitrogen-containing In-Sn oxides, and nitrogen In-Ga oxides containing nitrogen, In-Zn oxides containing nitrogen, and Sn oxides containing nitrogen Materials such as nitrogen-containing in oxides and metal nitride films (InN, SnN, etc.) can be used. These materials have a work function of 5 eV (electron volts) or more. These contain nitrogen. By using a metal oxide as the scanning line (gate electrode), the structure of transistor 103 A transistor that can vary its positive voltage in the positive direction and has so-called normally-off characteristics. A zista can be realized. For example, when using an In-Ga-Zn oxide containing nitrogen, a small amount However, if the nitrogen concentration is higher than that of the oxide semiconductor film 111, specifically if the nitrogen concentration is 7 atomic percent or higher, n-Ga-Zn oxides can be used.

[0096] In the scanning line 107 and capacitance line 115, low-resistance materials such as aluminum and copper are used. This is preferable. Using aluminum or copper reduces signal delay and improves display quality. It is possible. However, aluminum has low heat resistance, and hillocks, whiskers, or Defects due to migration are likely to occur. To prevent aluminum migration... Therefore, aluminum can be combined with molybdenum, titanium, tungsten, etc., which are more soluble than aluminum. It is preferable to laminate metal materials with high point density. Also, when using copper, migration To prevent defects caused by copper and the diffusion of copper elements, molybdenum, titanium, tungsten, etc. are used. It is preferable to laminate metal materials with higher melting points.

[0097] Furthermore, as shown in Figures 4 and 5, the scan line 107 scans the oxide semiconductor film 111. It is preferable to provide it in a shape that can be provided within the region of 107. As shown in Figure 4, acid The oxide semiconductor film 111 is provided in a region where it has a protruding shape. It is preferable to make it possible to place it inside the scan line 107. Therefore, the side of the substrate 102 opposite to the side on which the scan lines 107 are provided (the back side of the substrate 102) Light emitted from (in liquid crystal display devices, the light from the backlight or other light source) is scanned along scan line 1 Because 07 blocks light, the electrical characteristics of transistor 103 (e.g., threshold voltage) fluctuate. Alternatively, the decline can be suppressed.

[0098] The gate insulating film 127 is, for example, silicon oxide, silicon oxide nitride, silicon oxide nitride, Silicon nitride, aluminum oxide, hafnium oxide, gallium oxide, or Ga-Zn metals It is provided in a single-layer structure or a laminated structure using an insulating material such as an oxide. Note that the oxide semiconductor film In order to improve the interface characteristics with 111, in the gate insulating film 127, at least the region in contact with the oxide semiconductor film 111 is preferably formed of an oxide insulating film.

[0099] Further, by providing an insulating film having a barrier property against oxygen, hydrogen, water, etc. on the gate insulating film 127, it is possible to prevent the diffusion of oxygen contained in the oxide semiconductor film 111 to the outside and the intrusion of hydrogen, water, etc. from the outside into the oxide semiconductor film 111. Examples of the insulating film having a barrier property against oxygen, hydrogen, water, etc. include an aluminum oxide film, an aluminum oxynitride film, a gallium oxide film, a gallium oxynitride film, a yttrium oxide film, a yttrium oxynitride film, a hafnium oxide film, a hafnium oxynitride film, a silicon nitride film, etc.

[0100] Further, as the gate insulating film 127, hafnium silicate (HfSiO x ), hafnium silicate having nitrogen (HfSi O y O z N x ), hafnium aluminate having nitrogen (HfAl O y O z N 21 ), high-k materials such as hafnium oxide and yttrium oxide are used to reduce the gate leakage current of the transistor 103.

[0101] Further, the gate insulating film 127 preferably has the following laminated structure. As the first silicon nitride film, a silicon nitride film with a small amount of defects is provided, and as the second silicon nitride film on the first silicon nitride film, a silicon nitride film with a small amount of hydrogen desorption and ammonia desorption is provided. ​​​​​​​​​, on the second silicon nitride film, there is a stacked structure provided with any one of the insulating oxide films that can be applied as the gate insulating film 127. It is a stacked structure in which any one of them is provided.

[0102] As the second silicon nitride film, in the temperature programmed desorption gas analysis method, the desorption amount of hydrogen molecules is 5 ×10 21 molecules / cm 3 less than, preferably 3×10 21 molecules / cm 3 or less, more preferably even more preferably 1×10 21 molecules / cm 3 or less, and the desorption amount of ammonia molecules is 1×10 22 molecules / cm 3 less than, preferably 5×10 21 molecules / cm 3 or less, more preferably 1×10 2 1 molecules / cm 3 or less. It is preferable to use a nitride insulating film. By using the first silicon nitride film and the second silicon nitride film as part of the gate insulating film 127, a gate insulating film with a small defect amount and a small desorption amount of hydrogen and ammonia can be formed as the gate insulating film 127. As a result, it is possible to reduce the amount of hydrogen and nitrogen contained in the gate insulating film 127 that moves to the oxide semiconductor film 111.

[0103] In a transistor using an oxide semiconductor, when there is a trap level (also referred to as an interface level) at the interface between the oxide semiconductor film and the gate insulating film or in the gate insulating film, it causes fluctuations in the threshold voltage of the transistor, typically fluctuations in the negative direction of the threshold voltage, and an increase in the subthreshold swing coefficient (S value) indicating the gate voltage required for the drain current to change by one digit when the transistor is in the on state. As a result, for each transistor, the electrical ​ There is a problem that the properties fluctuate. For this reason, nitride with a low defect rate is used as the gate insulating film. By using a silicon film, and by providing an oxide insulating film in the region in contact with the oxide semiconductor film 111, By doing so, the negative shift in the threshold voltage is reduced, and the increase in the S value is suppressed. It is possible.

[0104] The thickness of the gate insulating film 127 is 5 nm or more and 400 nm or less, preferably 10 nm or more. The wavelength should be 00 nm or less, more preferably 50 nm to 250 nm.

[0105] The oxide semiconductor film 111 and the oxide semiconductor film 119 have an amorphous structure, a single crystal structure, or multiple It can have a crystalline structure. Furthermore, the thickness of the oxide semiconductor film 111 is 1 nm or more. less than or equal to nm, more preferably 1 nm to 50 nm, more preferably 1 nm to 30 nm More preferably, the wavelength should be between 3 nm and 20 nm.

[0106] Furthermore, oxide semiconductor film 111 and oxide semiconductor film 119 are composed of the same metal element. . As an oxide semiconductor applicable to the oxide semiconductor film 111, the energy gap is 2 eV or less. The above is preferably 2.5 eV or more, more preferably 3 eV or more. By using an oxide semiconductor with a wide G-gap, the off-current of transistor 103 is reduced. It is possible.

[0107] The oxide semiconductor applicable to the oxide semiconductor film 111 is at least indium (In) It is preferable that it is a metal oxide containing zinc (Zn). Alternatively, both In and Zn are used. It is preferable to include it. Furthermore, the variation in the electrical characteristics of the transistor using the oxide semiconductor is To reduce it, it is preferable to have one or more of the stabilizers together with them.

[0108] Examples of the stabilizer include gallium (Ga), tin (Sn), hafnium (Hf), al uminum (Al), or zirconium (Zr), etc. Further, other stabilizers include lanthanoids such as lanthanum (La), cerium (Ce), praseodymium (P r), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium ( Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium ( Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc.

[0109] Examples of the oxide semiconductor applicable to the oxide semiconductor film 111 and the oxide semiconductor film 119 include, for example, as the oxide semiconductor, indium oxide, tin oxide, zinc oxide, an oxide containing two kinds of metals such as In-Zn-based oxide, Sn-Zn-based oxide, Al-Zn-based oxide, Zn- Mg-based oxide, Sn-Mg-based oxide, In-Mg-based oxide, In-Ga-based oxide, an oxide containing three kinds of metals such as In-Ga-Zn-based oxide (also denoted as IGZO), In -Al-Zn-based oxide, In-Sn-Zn-based oxide, Sn-Ga-Zn-based oxide, Al- Ga-Zn-based oxide, Sn-Al-Zn-based oxide, In-Hf-Zn-based oxide, In-Z r-Zn-based oxide, In-Ti-Zn-based oxide, In-Sc-Zn-based oxide, In-Y- Zn-based oxide, In-La-Zn-based oxide, In-Ce-Zn-based oxide, In-Pr-Z n-based oxide, In-Nd-Zn-based oxide, In-Sm-Zn-based oxide, In-Eu-Zn -based oxide, In-Gd-Zn-based oxide, In-Tb-Zn-based oxide, In-Dy-Zn-based oxide, In-Ho-Zn-based oxide, In-Er-Zn-based oxide, In-Tm-Zn-based oxide, In-Yb-Zn-based oxide, In-Lu-Zn-based oxide, etc. ​​​In-Gd-Zn oxides, In-Tb-Zn oxides, In-Dy-Zn oxides Oxides, In-Ho-Zn oxides, In-Er-Zn oxides, In-Tm-Zn acids In-Yb-Zn oxides, In-Lu-Zn ​​oxides, and oxides containing four types of metals. The substances are In-Sn-Ga-Zn oxides, In-Hf-Ga-Zn oxides, and In-A l-Ga-Zn oxides, In-Sn-Al-Zn oxides, In-Sn-Hf-Zn oxides Oxides and In-Hf-Al-Zn oxides can be used.

[0110] Here, an In-Ga-Zn oxide is an oxide having In, Ga, and Zn as its main components. It refers to the material itself, and the ratio of In, Ga, and Zn is irrelevant. Also, other than In, Ga, and Zn... It may contain metallic elements.

[0111] In addition, as an oxide semiconductor, InMO3(ZnO) m Materials represented by (m>0) are used. It may be present. Note that M is one or more metallic elements selected from Ga, Fe, Mn, and Co. This indicates a metallic element, or an element used as a stabilizer as described above.

[0112] For example, In:Ga:Zn=1:1:1 (=1 / 3:1 / 3:1 / 3), In:Ga: Zn=2:2:1 (=2 / 5:2 / 5:1 / 5), or In:Ga:Zn=3:1: By using an In-Ga-Zn metal oxide with an atomic ratio of 2 (=1 / 2:1 / 6:1 / 3) This is possible. Alternatively, In:Sn:Zn=1:1:1 (=1 / 3:1 / 3:1 / 3), In:Sn:Zn = 2:1:3 (= 1 / 3:1 / 6:1 / 2) or In:Sn:Zn In-Sn-Zn metal oxides with an atomic ratio of 2:1:5 (=1 / 4:1 / 8:5 / 8). It is advisable to use the above. Note that the atomic ratio of metal elements contained in the metal oxide is considered an error. Includes a variation of plus or minus 20% in the atomic ratio.

[0113] However, this is not limited to these, and may include any other semiconductor characteristics and electrical characteristics (field effect mobility, etc.) required. Depending on the threshold voltage, variation, etc., an appropriate atomic ratio should be used. To obtain the semiconductor properties described above, the carrier density, impurity concentration, defect density, metal elements, and oxygen are all important. It is preferable to make the atomic ratio, interatomic distance, density, etc., appropriate. For example, In-S High field-effect mobility can be obtained relatively easily with n-Zn oxides. However, In -Even with Ga-Zn oxides, by lowering the bulk defect density, the field-effect mobility can be increased. It can be raised.

[0114] The oxide semiconductor film 119 uses an oxide semiconductor applicable to the oxide semiconductor film 111. This can be done. In addition, an oxide semiconductor film 111 is formed and an oxide semiconductor film 119 is formed. Since this is possible, the oxide semiconductor film 119 is the acid that constitutes the oxide semiconductor film 111. Contains metallic elements of ionized semiconductors.

[0115] Insulator functioning as a protective insulating film for transistor 103 and a dielectric film for retaining capacitance 105. The film 129, insulating film 131, and insulating film 132 are materials applicable to the gate insulating film 127. This is an insulating film using [a specific material]. In particular, insulating film 129 and insulating film 131 are made of oxide insulating film, and the insulating film is [a specific material]. It is preferable that 132 be a nitride insulating film. Then, impurities such as hydrogen and water from the outside enter transistor 103 (especially oxide semiconductor film 111). This can prevent intrusion. Note that the insulating film 129 may be omitted.

[0116] Furthermore, one or both of the insulating film 129 and insulating film 131 contain oxygen that satisfies the stoichiometric composition. It is preferable that the oxide insulating film contains more oxygen than this. To prevent the desorption of oxygen from the semiconductor film 111, and to prevent the acid contained in the oxygen-rich region By moving elements to the oxide semiconductor film 111, it becomes possible to reduce oxygen vacancies. For example, The amount of oxygen molecules released by thermal desorption gas analysis (hereinafter referred to as TDS analysis) , 1.0 × 10 18 molecule / cm 3 By using the above-mentioned oxide insulating film, an oxide semiconductor film 1 The oxygen vacancies contained in 11 can be reduced. Note that insulating film 129 and insulating film 131 A region containing an excess of oxygen in one or both of the following (oxygen-rich region) compared to the stoichiometric composition. It may also be an oxide insulating film in which a portion exists, and at least the oxide semiconductor film 111 and The presence of an oxygen-rich region in the superimposed region leads to the desorption of oxygen from the oxide semiconductor film 111. This prevents the oxygen in the oxygen-excess region from moving to the oxide semiconductor film 111. This makes it possible to reduce oxygen deficiency.

[0117] The insulating film 131 is an oxide insulating film containing more oxygen than satisfactorily satisfying the stoichiometric composition. In this case, the insulating film 129 is preferably an oxide insulating film that permeates oxygen. Insulating film 129 In this case, all oxygen that enters the insulating film 129 from the outside does not pass through the insulating film 129, and the insulating film Some oxygen remains in 129. Also, it is already contained in the insulating film 129, and insulating film 1 Some oxygen also moves from 29 to the outside. Therefore, the insulating film 129 is an acid with a large oxygen diffusion coefficient. A dielectric insulating film is preferred.

[0118] Furthermore, since the insulating film 129 is in contact with the oxide semiconductor film 111, it only allows oxygen to pass through. Rather, it is an oxide insulating film that can reduce the interface state density with the oxide semiconductor film 111. Preferably, the insulating film 129 is an oxide insulating film with a lower defect density in the film than the insulating film 131. It is preferable that the g value obtained by electron spin resonance measurement is 2.001(E'). - The spin density of center is 3.0 × 10 17 spins / cm 3 The following, preferably 5.0×10 16 spins / cm 3 The following are oxide insulating films. Note that electron spin resonance measurements The spin density of a g-value of 2.001, determined by the constant, is the dangling bond contained in the insulating film 129. This corresponds to the quantity of existence.

[0119] The thickness of the insulating film 129 is 5 nm or more and 150 nm or less, preferably 5 nm or more and 50 nm or less. The thickness of the insulating film 131 is preferably 10 nm or more and 30 nm or less. The wavelength can be 30 nm to 500 nm, preferably 150 nm to 400 nm. Cut.

[0120] Furthermore, the insulating film 129 provided on the oxide semiconductor film 111 is permeable to oxygen, and The oxide insulating film 131 is an oxide insulating film that can reduce the interface state density with the oxide semiconductor film 111. an oxide insulating film containing an oxygen-rich region or containing more oxygen than satisfies the stoichiometric composition. By using an oxide insulating film, it becomes easier to supply oxygen to the oxide semiconductor film 111. This prevents oxygen from being released from the oxide semiconductor film 111, and also prevents oxygen from being contained in the insulating film 131. The oxygen is transferred to the oxide semiconductor film 111, and the oxygen vacancies contained in the oxide semiconductor film 111 are filled. This makes it possible to achieve normally-on characteristics in transistor 103. It can be suppressed.

[0121] Furthermore, one or both of the insulating film 129 and insulating film 131 may be silicon oxidiznitride or acid nitride. When using an oxide insulating film containing nitrogen, such as silicon dioxide, the nitrogen concentration obtained from SIMS is: SIMS detection limit above 3 × 10 20 atoms / cm 3 Less than 1 × 10 18 a toms / cm 3 The above 1 x 10 20 atoms / cm 3 The following is preferable. This allows nitrogen to be transferred to the oxide semiconductor film 111 contained in the transistor 103. The amount can be reduced. Also, by doing so, the nitrogen-containing oxide insulating film itself This can reduce the amount of defects.

[0122] When insulating film 132 is a nitride insulating film, one or both insulating film 129 and insulating film 131 It is preferable that the insulating film has barrier properties against nitrogen. For example, a dense oxide insulating film. By forming a membrane, it can have a barrier property against nitrogen, specifically at 25°C An oxide insulating material whose etching rate with 0.5 wt% hydrofluoric acid is 10 nm / min or less. It is preferable to form a film.

[0123] A nitride insulating film with a low hydrogen content can be provided as the insulating film 132. As an insulating film, for example, the amount of hydrogen molecules released, as measured by TDS analysis, is 5.0 × 10 21 / cm 3 It is less than 3.0 × 10 21 / cm 3It is less than, and further Preferably 1.0 × 10 21 / cm 3 It is a nitride insulating film that is less than [amount missing].

[0124] Furthermore, the above nitride insulating film has excellent step coverage properties, thus protecting transistor 103. It is useful as a border membrane.

[0125] The insulating film 132 has a thickness that allows it to perform the function of suppressing the intrusion of impurities such as hydrogen and water from the outside. To explain. For example, 50 nm to 200 nm, preferably 50 nm to 150 nm. Furthermore, it is more preferably 50 nm to 100 nm.

[0126] Furthermore, by using a nitride insulating film as the insulating film 132 provided on the insulating film 131, This can prevent impurities such as hydrogen and water from entering the oxide semiconductor film 111 from the outside. Furthermore, by providing a nitride insulating film with a low hydrogen content as the insulating film 132, This can suppress fluctuations in the electrical characteristics of ZISTA 103.

[0127] Furthermore, between insulating film 131 and insulating film 132, by CVD using organic silane gas A silicon oxide film may be formed. This silicon oxide film has excellent step coverage properties. Therefore, it is useful as a protective insulating film for transistor 103. The silicon oxide film is 30 It can be provided in the range of 0 nm to 600 nm. Ethyl silicate can be used as the organic silane gas. (TEOS: chemical formula Si(OC2H5)4), tetramethylsilane (TMS: chemical formula Si (CH3)4), tetramethylcyclotetrasiloxane (TMCTS), octamethyl tetramethyl Clotetrasiloxane (OMCTS), hexamethyldisilazane (HMDS), trieth Xysilane (SiH(OC2H5)3), Trisdimethylaminosilane (SiH(N(C Silicon-containing compounds such as H3)2)3) can be used.

[0128] The pixel electrode 121 is formed using a light-transmitting conductive film. indium tin oxide, indium oxide including tungsten oxide, tungsten oxide Indium zinc oxide containing titanium oxide, indium oxide containing titanium oxide, indium oxide containing titanium oxide Dium-tin oxide, indium zinc oxide, indium-tin oxide with added silicon oxide, etc. It is provided with a conductive material that has light-transmitting properties.

[0129] The substrate 150 can use a substrate that is applicable to the substrate 102.

[0130] The light-shielding film 152, also known as the black matrix, is a backlight in liquid crystal display devices. This includes suppressing light leakage from light sources and preventing color mixing that occurs when using color filters for color display. It is provided to suppress contrast reduction caused by, etc. The light-shielding film 152 is a commonly used It can be provided using materials that have light-shielding properties, such as metal or pigment. Examples include organic resins. The light-shielding film 152 is superimposed on the transistor 103. In addition to the region, there are also pixel sections 10 such as the scan line drive circuit 104 and the signal line drive circuit 106 (see Figure 1). It may be placed in a region other than 0.

[0131] Furthermore, in the pixel section 100, light of a predetermined wavelength is transmitted between the light-shielding films provided on each pixel. A colored film having a light-blocking function may be provided. Furthermore, a light-shielding film and a colored film, and a counter electrode. An overcoat film may be provided between them.

[0132] The counter electrode 154 is provided using a material suitable for use with the pixel electrode 121.

[0133] The alignment films 156 and 158 are provided using commonly available materials such as polyamide. It is possible.

[0134] Liquid crystal 160 includes thermotropic liquid crystals, low molecular weight liquid crystals, polymer liquid crystals, polymer dispersed liquid crystals, Ferroelectric liquid crystals, antiferroelectric liquid crystals, etc., can be used. These liquid crystal materials are suitable for the conditions. More specifically, the cholesteric phase, smectic phase, cubic phase, chiral nematic phase, etc. It indicates the aspect of the planet, etc.

[0135] Furthermore, the liquid crystal 160 may be a liquid crystal exhibiting a blue phase without using an alignment layer. This is one of the liquid crystal phases, and as the temperature of cholesteric liquid crystal is increased, the cholesteric phase is replaced by an equal This is the phase that appears just before the transition to the chromatic phase. The blue phase only appears within a narrow temperature range. Furthermore, a liquid crystal composition mixed with a chiral agent is used to improve the temperature range. It is formed of an organic resin, and since the organic resin contains hydrogen or water, one aspect of the present invention This may degrade the electrical characteristics of transistors in semiconductor devices. Therefore, liquid crystal As 160, by using the blue phase, one aspect of the present invention is a semiconductor without using organic resin. Body devices can be fabricated, and highly reliable semiconductor devices can be obtained.

[0136] Furthermore, the liquid crystal element 108, based on the display mode of the liquid crystal element 108, the pixel electrode 12 The shape of 1 and the opposing electrode 154, etc., and the formation of protrusions called ribs, etc., are appropriately modified. It can be changed.

[0137] <Methods for fabricating semiconductor devices> Next, the method for fabricating the above-mentioned semiconductor device will be explained using Figures 6 and 7.

[0138] First, scan lines 107 and capacitance lines 115 are formed on the substrate 102, scan lines 107 and capacitance lines An insulating film 126 is formed so as to cover 115, which will later be processed into a gate insulating film 127. An oxide semiconductor film 111 is formed in the region overlapping with the 126 scan lines 107, and later the pixel electrode 1 An oxide semiconductor film 119 is formed so as to overlap with the region where 21 is formed (see Figure 6(A)). see).

[0139] Scanning line 107 and capacitance line 115 have a conductive film formed using the materials listed above, and the conductive It can be formed by forming a mask on an electrical film and then processing using the mask. The film is deposited using various methods such as vapor deposition, CVD, sputtering, and spin coating. The thickness of the conductive film is not particularly limited, and the formation time and desired resistance can be adjusted. The rate and other factors can be taken into consideration when determining the mask. For example, the first photolithography A resist mask can be formed by the process. Furthermore, the processing of the conductive film is This can be done by dry etching, wet etching, or both.

[0140] The insulating film 126 is made using a material applicable to the gate insulating film 127 by CVD or sprucing. It can be formed using various film deposition methods such as the taring method. Also, the gate insulating film 12 When applying gallium oxide to 7, use MOCVD (Metal Organic Chemistry). The insulating film 126 is formed using the (mical Vapor Deposition) method. It is possible.

[0141] The oxide semiconductor film 111 and the oxide semiconductor film 119 use the oxide semiconductors listed above. A oxide semiconductor film is formed, a mask is formed on the oxide semiconductor film, and the mask is used It can be formed by processing. For this reason, oxide semiconductor film 111 and oxide semiconductor film 119 is composed of the same metallic element. The oxide semiconductor film is produced by sputtering, coating, etc. It can be formed using methods such as pulsed laser deposition and laser ablation. By using a printing method, the element-separated oxide semiconductor film 111 and oxide semiconductor film 11 9 can be formed directly on the gate insulating film 127 by sputtering. When forming a semiconductor film, the power supply for generating plasma is an RF power supply, AC power supply, etc. A power supply unit or DC power supply unit can be used as appropriate. The sputtering gas is a rare gas. A suitable gas may be used, such as argon (typically), oxygen, or a mixture of a noble gas and oxygen. In the case of a mixed gas of a noble gas and oxygen, it is preferable to increase the gas ratio of oxygen to the noble gas. Furthermore, the target can be appropriately selected according to the composition of the oxide semiconductor film to be formed. The mask in question is a resist formed, for example, by a second photolithography process. It can be used as a mask. Furthermore, the processing of the oxide semiconductor film is done by dry etching and This can be done by either or both of the following methods: etching to the desired shape. To enable etching, the etching conditions (etching gas, etching solution, etching) should be adjusted according to the material. Set the time, temperature, etc. as appropriate.

[0142] After forming oxide semiconductor films 111 and 119, heat treatment is performed, and oxide It is preferable to dehydrogenate or dehydrate the semiconductor film 111 and the oxide semiconductor film 119. The temperature of the heat treatment is typically 150°C or higher and below the substrate strain point, preferably 200°C. The heating temperature shall be 450°C or higher, and more preferably 300°C or higher and 450°C or lower. The process is performed on the oxide semiconductor film before it is processed into oxide semiconductor film 111 and oxide semiconductor film 119. That's fine.

[0143] In this heat treatment, the heat treatment apparatus is not limited to an electric furnace, but also includes a heated gas or other medium. It may be a device that heats the object to be processed by heat conduction or thermal radiation. For example, GRTA (Gas Rapid Thermal Anneal) equipment, LRTA (La mp Rapid Thermal Annealing (RTA) devices, etc. A stermal Anneal (LRTA) device can be used. The LRTA device uses halogen lamps. P, metal halide lamp, xenon arc lamp, carbon arc lamp, high-pressure sodium The light (electromagnetic waves) emitted from lamps such as um lamps and high-pressure mercury lamps is used to treat the object being processed. It is a device for heating objects. A GRTA device is a device that performs heat treatment using high-temperature gas. ru.

[0144] The heat treatment involves nitrogen, oxygen, and ultra-dry air (with a water content of 20 ppm or less, preferably). Air (1 ppm or less, preferably 10 ppb or less), or noble gas (argon, helium, etc.) The procedure should be carried out under the following conditions: nitrogen, oxygen, ultra-dry air, or noble gases with hydrogen and water. It is preferable that the following are not included. After heating in an inert gas atmosphere, heat in an oxygen atmosphere. This is acceptable. The processing time should be between 3 minutes and 24 hours.

[0145] Furthermore, between the substrate 102 and the scan lines 107 and capacitance lines 115 and the gate insulating film 127 When an underlayer insulating film is provided, the underlayer insulating film may be silicon oxide, silicon oxide nitride, or nitride Silicon, silicon nitride, gallium oxide, hafnium oxide, yttrium oxide, oxide It can be formed from aluminum, aluminum oxide nitride, etc. Furthermore, the underlying insulating film and Then, silicon nitride, gallium oxide, hafnium oxide, yttrium oxide, aluminum oxide By forming it with um, impurities, typically alkali metals, water, and hydrogen, are removed from the substrate 102. This can suppress the diffusion of such substances into the oxide semiconductor film 111. The underlying insulating film is sputtering It can be formed using the galvanic acid method or the CVD method.

[0146] Next, an opening 123 reaching the capacitance line 115 is formed in the insulating film 126 to create the gate insulating film 127 After forming, the signal line 109, which includes the source electrode of transistor 103, and transistor 10 The conductive film 113, which includes the drain electrode 3, the oxide semiconductor film 119, and the capacitance line 115 are electrically connected. A conductive film 125 is formed to connect to it (see Figure 6(B)).

[0147] The opening 123 is such that a portion of the region overlapping with the capacitance line 115 of the insulating film 126 is exposed. A mask is formed by a third photolithography process, and the mask is used for processing. It can be formed by the same process as the scan line 107 and capacitance line 115. It can be done in the same way.

[0148] The signal line 109, conductive film 113 and conductive film 125 are connected to the signal line 109, conductive film 113 and conductive film 125. A conductive film is formed using a material applicable to the conductive film 125, and a fourth photolithography is applied to the conductive film. The mask is formed by a photography process, and then processed using that mask. The mask and the processing shall be carried out in the same manner as the scan line 107 and the capacitance line 115. This can be done. After the signal line 109 and conductive film 113 are formed, the oxide semiconductor film 111 By cleaning the surface, fluctuations in the electrical characteristics of transistor 103 can be reduced. For example, a diluted phosphoric acid solution can be used, specifically 85% phosphoric acid at 100% A phosphoric acid solution diluted to twice its original concentration can be used.

[0149] Next, oxide semiconductor film 111, oxide semiconductor film 119, signal line 109, conductive film 113, An insulating film 128 is formed on the conductive film 125 and the gate insulating film 127, and an insulating film 128 is formed on the insulating film 128. A border film 130 is formed, and an insulating film 133 is formed on the insulating film 130 (see Figure 7(A)). It is preferable that insulating film 128, insulating film 130, and insulating film 133 be formed in a continuous manner. In this way, the interfaces of insulating film 128, insulating film 130, and insulating film 133 This helps to prevent impurities from being mixed in.

[0150] The insulating film 128 is made using a material applicable to the insulating film 129 by CVD or sputtering. It can be formed using various film deposition methods such as the galvanizing method. The insulating film 130 is an insulating film 131 It can be formed using materials applicable to the insulating film 132. It can be formed using [this method].

[0151] An oxide insulating film that can reduce the interface state density with the oxide semiconductor film 111 is applied to the insulating film 129. In this case, the insulating film 128 can be formed using the following formation conditions. Note that here, the oxidation This section describes the case where a silicon oxide film or a silicon oxidiznitride film is formed as an insulating film. The formation conditions involve placing a substrate in the vacuum-evacuated processing chamber of a plasma CVD apparatus. Maintain the temperature between 80°C and 400°C, more preferably between 200°C and 370°C, in the processing chamber. The raw material gases, a silicon-containing depositing gas and an oxidizing gas, are introduced, and the pressure in the processing chamber is increased. The pressure is set to 20 Pa or more and 250 Pa or less, more preferably 40 Pa or more and 200 Pa or less. This refers to the conditions for supplying high-frequency power to electrodes installed in the laboratory.

[0152] Typical examples of silicon-containing sedimentary gases include silanes, disilanes, trisilanes, and fluorides. Examples include silanes. Oxidizing gases include oxygen, ozone, nitrous oxide, and nitrogen dioxide. There is.

[0153] Furthermore, by increasing the amount of oxidizing gas relative to the silicon-containing sedimentary gas to more than 100 times, It is possible to reduce the hydrogen content contained in the insulating film 128 (insulating film 129), and This can reduce dangling bonds contained in the insulating film 128 (insulating film 129). Oxygen moving from insulating film 130 (insulating film 131) goes to insulating film 128 (insulating film 129). Because it may be trapped by the dangling bond contained, insulating film 128 (insulating film) If the dangling bond contained in 129) is reduced, the insulating film 130 (insulating film 13 1) The oxygen contained in the oxide semiconductor film 111 can be efficiently transferred to the oxide semiconductor film 111. It is possible to reduce the oxygen vacancies contained in the conductive film 111. As a result, oxide semiconductor This reduces the amount of hydrogen mixed into the film 111, and also reduces the oxygen vacancies contained in the oxide semiconductor film 111. It is possible to reduce this.

[0154] The insulating film 131 is an oxide insulating film containing the above-mentioned oxygen-rich region or oxygen satisfying the stoichiometric composition. When an oxide insulating film containing more oxygen is to be formed, the insulating film 130 is formed using the following conditions It can be formed. Here, the oxide insulating film is a silicon oxide film or silicon oxide nitride film. This section describes the process for forming a film. The formation conditions are as follows: Vacuum evacuation of the plasma CVD apparatus. The substrate placed in the processing chamber is heated to a temperature of 180°C to 260°C, more preferably 180°C. Maintain a temperature between 230°C and 330°C, introduce the raw material gas into the processing chamber, and maintain a pressure of 10°C inside the processing chamber. The pressure should be between 0 Pa and 250 Pa, more preferably between 100 Pa and 200 Pa, and the processing should be performed accordingly. 0.17 W / cm² applied to electrodes installed in the room. 2 More than 0.5W / cm 2 More preferably, It is 0.25 W / cm² 2 More than 0.35W / cm 2 The following are the conditions for supplying high-frequency power.

[0155] The raw material gas for insulating film 130 can be a raw material gas applicable to the formation of insulating film 128. Cut.

[0156] As a condition for forming the insulating film 130, the above pressure is applied in a processing chamber with the above power density of high-frequency electricity. By supplying power, the decomposition efficiency of the raw material gas in the plasma increases, and the amount of oxygen radicals increases. As the oxidation of the raw material gas progresses, the oxygen content in the insulating film 130 becomes greater than the stoichiometric composition. The amount also increases. However, if the substrate temperature is the above temperature, the bonding force between silicon and oxygen Because it is weak, some of the oxygen is removed by heating. As a result, the oxygen that satisfies the stoichiometric composition... It can form an oxide insulating film that contains more oxygen, and some of the oxygen is removed by heating. In addition, an insulating film 128 is provided on the oxide semiconductor film 111. In the process of forming the film 130, the insulating film 128 becomes a protective film for the oxide semiconductor film 111. As a result, even when the insulating film 130 is formed using high-frequency power with high power density, the oxide semiconductor... Damage to membrane 111 can be suppressed.

[0157] Furthermore, increasing the thickness of the insulating film 130 increases the amount of oxygen that is released by heating. Therefore, it is preferable that the insulating film 130 be thicker than the insulating film 128. By providing the edge film 128, good coverage can be achieved even when the insulating film 130 is made thick. can.

[0158] When the insulating film 132 is made of a nitride insulating film with a low hydrogen content, the insulating film 133 takes the following form. It can be formed using the following conditions. Here, a silicon nitride film is used as the nitride insulating film. The following describes the conditions under which this occurs. The formation conditions are as follows: The substrate placed in the laboratory is heated to a temperature of 80°C to 400°C, more preferably 200°C to 37°C. Maintain a temperature below 0°C, introduce the raw material gas into the processing chamber, and maintain a pressure of 100 Pa or higher within the processing chamber. The pressure shall be 250 Pa or less, preferably 100 Pa or more and 200 Pa or less, and installed in the processing chamber. This is the condition for supplying high-frequency power to the electrodes.

[0159] The raw material gases for the insulating film 133 are silicon-containing depositing gas, nitrogen, and ammonia. It is preferable to use [a specific type of gas]. Typical examples of silicon-containing sedimentary gases include silane and disila. Examples include nitrates, trisilanes, and silane fluorides. Furthermore, the nitrogen flow rate is relative to the ammonia flow rate. It is preferable that the ratio be between 5 and 50 times, and more preferably between 10 and 50 times. By using ammonia as a raw material gas, the sedimentary gas containing silicon and nitrogen are decomposed. This can be promoted by ammonia being stimulated by plasma energy and thermal energy. Dissociate, and the energy released by dissociation binds the silicon-containing sedimentary gas molecules and This is because it contributes to the breakdown of nitrogen molecule bonds. In this way, the hydrogen content is low. Furthermore, it forms a silicon nitride film that can suppress the intrusion of impurities such as hydrogen and water from the outside. It is possible.

[0160] Furthermore, between insulating film 131 and insulating film 132, by CVD using organic silane gas When forming the silicon oxide film, use the CVD method with the organic silane gases listed above. This forms a silicon oxide film on the insulating film 130.

[0161] At least the insulating film 130 is formed, followed by a heat treatment to create the insulating film 128 or insulating film 13 At least the oxygen contained in 0 is transferred to the oxide semiconductor film 111, It is preferable to reduce the oxygen deficiency. The heat treatment is performed on the oxide semiconductor film 111 and Refer to the details of the heat treatment for dehydrogenating or dehydrating the oxide semiconductor film 119 and carry it out as appropriate. It is possible.

[0162] Furthermore, one preferred procedure for forming the transistor 103 is to use a chemical amount of insulating film 130. An oxidative atom contains more oxygen than satisfies the theoretical composition, and some of the oxygen is removed upon heating. After forming the edge film and the insulating film 130, a heat treatment at 350°C is performed, and the above-listed properties A silicon oxide film was formed using a CVD method with a silane gas and the substrate temperature maintained at 350°C. A nitride insulating film with a low hydrogen content is formed as insulating film 132, with the substrate temperature set to 350°C. That is what it is.

[0163] Next, in the region where insulating film 128, insulating film 130, and insulating film 133 overlap with the conductive film 113 After forming the mask by the fifth photolithography step, insulating film 128, insulating film 13 The 0 and insulating film 133 are etched to form an opening 117 that reaches the conductive film 113. Next, insulating film 129, insulating film 131, and insulating film 132 are formed (see Figure 7(B)). Pixel electrodes 121 are formed on the aperture 117 and the insulating film 132 (see Figure 5).

[0164] Aperture 117 can be formed in the same manner as aperture 123. Pixel electrode 121 is above Using the listed materials, a conductive film is formed that comes into contact with the conductive film 113 through the opening 117. A mask is formed on the conductive film by a sixth photolithography step, and the mask is used to process It can be formed by processing. Note that the mask and the processing are performed using scan lines 107 and capacitance. This can be done in the same way as line 115.

[0165] Next, an alignment film 158 is formed on the insulating film 132 and on the pixel electrode 121. Also, the substrate 1 A light-shielding film 152 is formed on 50. Furthermore, a counter electrode 154 is formed so as to cover the light-shielding film 152. Then, an alignment film 156 is formed on the counter electrode 154. Liquid crystal 160 is provided on the alignment film 158. Then, the substrate 150 is placed on the substrate 102 so that the alignment film 156 is in contact with the liquid crystal 160 and sealed. The substrate 102 and substrate 150 are fixed together with a material (not shown).

[0166] The alignment films 156 and 158 are produced using the above-mentioned materials by methods such as spin coating and printing. It can be formed by appropriately utilizing various film deposition methods.

[0167] The light-shielding film 152 was formed by sputtering using the materials listed above, and a mask was used. It can be formed by processing.

[0168] The counter electrode 154 is made using a material applicable to the pixel electrode 121, and is manufactured by CVD or sputtering. It can be formed using various film deposition methods such as the densification method.

[0169] The liquid crystal 160 can be directly provided on the alignment film 158 by a dispenser method (dropping method). Furthermore, after bonding substrate 102 and substrate 150 together, the liquid crystal 16 is formed using capillary action or the like. It is also possible to inject 0. In addition, the liquid crystal 160 has an alignment film 156 to facilitate alignment. Furthermore, it is preferable to perform a rubbing process on the orientation film 158.

[0170] By following the above steps, a semiconductor device according to one aspect of the present invention can be manufactured (see Figure 5). see).

[0171] <Variation 1> In a semiconductor device according to one aspect of the present invention, one electrode that constitutes the retaining capacitance functions The connection between the oxide semiconductor film and the capacitance line can be changed as appropriate. For example, the connection can be further opened To increase the capacitance ratio, a structure is adopted in which the semiconductor film is in direct contact with the capacitance line without an intervening conductive film. Yes, it is possible. A concrete example of this structure will be explained using Figures 8 and 9.

[0172] In the following diagrams showing modified examples, for clarity, the substrate 150 and the light-shielding film are shown separately. Components 152, counter electrode 154, alignment film 156, alignment film 158, and liquid crystal 160 are omitted. Furthermore, in the drawings showing modified examples, the reference numerals used in Figure 4 or Figure 5 shall be used as appropriate. In the modified examples below, only the differences from the structures shown in Figures 4 and 5 will be explained.

[0173] A specific example of this structure will be explained using Figures 8 and 9. Figure 8 is a top view of pixel 101. Figure 9(A) is a cross-sectional view between the dashed lines A1-A2 and B1-B2 in Figure 8. That is the case.

[0174] In the pixel 101 shown in Figures 8 and 9, one of the electrodes of the retaining capacitance 145 functions as... The oxide semiconductor film 119 is in direct contact with the capacitance line 115 and the aperture 143. (Figure 4) As shown in Figure 5, the holding capacity 105 allows the oxide semiconductor film 119 and the conductive film 125 to be absorbed without intermediary. Since the capacitance line 115 is in direct contact and the conductive film 125 that acts as a light-shielding film is not formed, the pixel The aperture ratio can be further increased. This is because, in Figure 6(A), the oxide semiconductor film 1 Before forming 11 and 119, an aperture is formed to expose capacitance line 115, and then the oxide semiconductor The films 111 and 119 should be formed.

[0175] Furthermore, in Figure 9, the opening 143 is provided only on the capacitance line 115, but as shown in Figure 10... The gate insulating film 127 is applied so that a portion of the capacitance line 115 and the substrate 102 are exposed. Forming a capacitance line 115 and an oxide semiconductor film 119 on the substrate 102, The area in contact between the conductive film 119 and the capacitance line 115 may be increased. This is shown in Figure 6(A). Before forming the oxide semiconductor films 111 and 119, the capacitance lines 115 and the substrate 102 are used. After forming the gate insulating film 127 such that a portion of each is exposed, the oxide semiconductor film 111, 119 should be formed. As a result, the aperture ratio can be increased, and the oxide semiconductor The conductivity of the film 119 is increased, and the oxide semiconductor film 119 can be easily made conductive. Therefore, the holding capacity of 146 can be easily made functional.

[0176] <Variation 2> In a semiconductor device according to one aspect of the present invention, one electrode that constitutes the retaining capacitance functions The connection between the oxide semiconductor film and the capacitance line can be changed as appropriate. For example, the semiconductor To reduce the contact resistance between the body film and the conductive film, the conductive film is applied along the outer periphery of the semiconductor film. They can be installed in contact with each other. A specific example of this structure will be explained using Figures 11 and 12. Figure 11 shows a top view of pixel 101 of this structure, and Figure 12(A) is a dot chain view of Figure 11. This is a cross-sectional view between lines A1-A2 and between dashed lines B1-B2, and Figure 12(B) is a cross-sectional view of Figure 11. This is a cross-sectional view between the dotted lines C1 and C2.

[0177] In the pixel 101 shown in Figures 11 and 12, the conductive film 167 is an oxide semiconductor film 11 It is in contact with the outer circumference of 9 and is provided in contact with the capacitance line 115 through the opening 123. Furthermore, the conductive film 167 is provided so as to cover the edge of the oxide semiconductor film 119. The film 167 is formed using the process of forming the signal line 109, the conductive film 113, and the conductive film 125. Therefore, since the conductive film 167 may have light-shielding properties, it can be formed in a loop shape. This is preferable. Furthermore, the larger the contact area between the conductive film 167 and the oxide semiconductor film 119, the better. As a result, the conductivity of the oxide semiconductor film 119 increases, and the oxide semiconductor film 119 easily becomes conductive. Because it can be configured in this way, it can easily function as one of the electrodes with a holding capacity of 165.

[0178] Furthermore, in the pixel 101 shown in Figures 11 and 12, the oxide semiconductor film 119 and capacitance To ensure that line 115 is in contact with the conductive film 167, the shape of the oxide semiconductor film 119 is appropriately changed. It is possible to obtain it.

[0179] Furthermore, the conductive film 167 is in contact with the oxide semiconductor film 119 with the loop-shaped portion separated. It may be provided as such.

[0180] <Variation 3> In a semiconductor device according to one aspect of the present invention, one electrode that constitutes the retaining capacitance functions The connection between the oxide semiconductor film and the capacitance line can be changed as appropriate. For example, see Figure 13 and As shown in Figure 14, the process of forming the signal line 109 is used to form the capacitance line 1 75 can be formed.

[0181] Figure 13 shows a top view of pixel 101 of this structure, and Figure 14 shows the dashed line A1- in Figure 13. This is a cross-sectional view between A2, between the dashed lines B1 and B2, and between the dashed lines D1 and D2.

[0182] Capacity line 175 is provided extending in a direction parallel to signal line 109. 09 and capacitance line 175 are electrically connected to the signal line drive circuit 106 (see Figure 1(A)). It is.

[0183] In the pixel 101 shown in Figures 13 and 14, provided on the oxide semiconductor film 119 The oxide semiconductor film 119 and the pixel electrode are connected via insulating film 129, insulating film 131, and insulating film 132. The region where 121 and 174 overlap has a holding capacity of 174.

[0184] When a capacitance line is provided in a direction parallel to the signal line 109, such as capacitance line 175, The raw shape is scanned by comparing it with the edges parallel to the signal line 109, as shown in pixel 101 in Figure 13. It is preferable that the side parallel to line 107 is longer. This is because the shape of the pixel is When the side parallel to signal line 109 is longer than the side parallel to trajectory line 107, In comparison, it is possible to reduce the area where the pixel electrode 121 and the capacitance line 175 overlap, and This is because it can improve the rate of participation.

[0185] <Variation 4> In a semiconductor device according to one aspect of the present invention, one electrode constituting the retaining capacitance, and the capacitance The line can be a semiconductor film (specifically, an oxide semiconductor film). See Figure 1 for a specific example. This will be explained using Figure 5. Note that here, the oxide semiconductor film 119 and described in Figures 4 and 5 will be used. We will only explain the oxide semiconductor film 198, which is different from capacitance line 115. Figure 15 shows this deformation. This is a top view of the example pixel 101, and in the pixel 101 shown in Figure 15, the retention capacity is 197. An oxide semiconductor film 198 is provided, which serves as both one electrode and a capacitance line. Line 198 has a region that extends parallel to signal line 109, and this region functions as a capacitance line. In the oxide semiconductor film 198, the region superimposed on the pixel electrode 121 has a retention capacitance of 197. It functions as one of the electrodes. The oxide semiconductor film 198 is located at the pixel 101 shown in Figure 15. This process utilizes the process of forming the oxide semiconductor film 111 contained in the transistor 103. It can be formed by [doing something].

[0186] The oxide semiconductor film 198 is superimposed on the scan line 107 in each pixel 101. It can be provided as a single oxide semiconductor film. In other words, the oxide semiconductor film 198 is 1 It is possible to provide a continuous oxide semiconductor film without separation in all pixels 101 of the row. ru.

[0187] Furthermore, the oxide semiconductor film 198 is made continuous without separation in all pixels 101 of one row. When provided as an oxide semiconductor film, the oxide semiconductor film 198 overlaps with the scan line 107, Due to the potential change in scan line 107, one of the electrodes of the capacitance line and retaining capacitance 197 is affected. This may not always be possible. Therefore, as shown in Figure 15, in each pixel 101, oxide semiconductor The film 198 is provided at intervals. The spaced oxide semiconductor film 198 is connected to the signal line 1 Using the conductive film 199 that can be formed by the process of forming 09 and the conductive film 113, electrically contact It is preferable to continue.

[0188] In Figure 15, the region that functions as a capacitance line of the oxide semiconductor film 198 is parallel to the signal line 109. Although the structure extends in one direction, the region that functions as a capacitance line extends in a direction parallel to the scan line 107. The structure may also be such that the region that functions with the capacitance line of the oxide semiconductor film 198 runs through it. In the case of a structure extending in a direction parallel to the probe line 107, the transistor 103 and the retaining capacitance 19 In 7, the oxide semiconductor film 111 and the oxide semiconductor film 198, the signal line 109 and the conductor It is necessary to provide an insulating film between the film 113 and the other element to electrically separate them.

[0189] As described above, an oxide semiconductor film is provided on the pixel, as shown in pixel 101 in Figure 15. By providing it as one of the electrodes and capacitance lines of the holding capacitance, the aperture ratio of the pixel can be improved. can.

[0190] <Variation 5> Furthermore, in the pixel 101 described as a modified example above, the pixel electrode 121 and the conductive film 113 Parasitic capacitance that occurs between or between the pixel electrode 121 and the conductive film 167 To reduce this, an organic insulating film can be provided in the region where the parasitic capacitance occurs. The organic insulating film can be partially provided in the pixel 101.

[0191] As the organic insulating film, photosensitive and non-photosensitive organic resins can be used, for example, acrylic Using resins, benzocyclobutene resins, epoxy resins, or siloxane resins, etc. This can be done. Furthermore, polyamide can be used as the organic insulating film.

[0192] After forming the insulating film using the materials listed above in order to partially provide the organic insulating film Processing of the insulating film may be necessary. The method for forming the organic insulating film is not particularly limited. Furthermore, the method can be appropriately selected depending on the material being used. For example, spin coating, dipping, and spray coating. Fabric, droplet ejection (inkjet), screen printing, offset printing, etc. are used. This can be done. Furthermore, by using a photosensitive organic resin as the organic insulating film, the organic This eliminates the need for a resist mask when forming an insulating film, simplifying the process.

[0193] <Variation 6> Furthermore, in a semiconductor device according to one aspect of the present invention, the configuration of the capacitance lines can be appropriately changed. Yes, it is possible. This structure will be explained using Figure 16. Note that the structure explained in Figure 4 will be explained here. Compared to capacitance line 115, the position of the capacitance line is different between two adjacent pixels. .

[0194] Figure 16 shows the area above adjacent pixels 401_1 and 401_2 in the direction of extension of signal line 409. This is a view drawing.

[0195] Scan lines 407_1 and 407_2 are parallel to each other and are connected to signal line 109. It is provided extending in a direction that is approximately perpendicular to the other. Between scan line 407_1 and scan line 407_2 Furthermore, a capacitance line 415 is provided parallel to each other with respect to scan lines 407_1 and 407_2. Furthermore, the capacitance line 415 is provided in the pixel 401_1, and the retaining capacitance 405_1 and the pixel It is connected to the holding capacity 405_2 provided in 401_2. Pixel 401_1 and Pixel 401 The top shape of _2 and the arrangement of its components are symmetrical with respect to the capacitance line 415.

[0196] Pixel 401_1 has transistor 403_1 and is connected to transistor 403_1. A pixel electrode 421_1 and a retention capacitor 405_1 are provided.

[0197] Transistor 403_1 is provided in the region where scan line 407_1 and signal line 409 intersect. Transistor 403_1 has at least an oxide having a channel-forming region. The semiconductor film 411_1, the gate electrode, the gate insulating film (not shown in Figure 16), and the source electrode It includes an electrode and a drain electrode. Note that in scan line 407_1, the oxide semiconductor film 4 The region overlapping with 11_1 functions as the gate electrode of transistor 403_1. Signal line In 409, the region superimposed with the oxide semiconductor film 411_1 is the region of transistor 403_1. It functions as a source electrode. In the conductive film 413_1, it overlaps with the oxide semiconductor film 411_1. The area to be covered functions as the drain electrode of transistor 403_1. Conductive film 413_1 The pixel electrode 421_1 is connected at the aperture 417_1.

[0198] The retained capacitance 405_1 is connected to the capacitance line 415 through the conductive film 425 provided in the opening 423. They are electrically connected. The retaining capacitance 405_1 is formed of a translucent oxide semiconductor. A dielectric film comprising an oxide semiconductor film 419_1, a light-transmitting pixel electrode 421_1, and a dielectric film And, included in transistor 403_1, a light-transmitting insulating film (not shown in Figure 16) It is constructed such that the holding capacity 405_1 is translucent.

[0199] Pixel 401_2 has transistor 403_2 and is connected to transistor 403_2. A storage capacity 405_2 is provided.

[0200] Transistor 403_2 is provided in the region where scan line 407_2 and signal line 409 intersect. Transistor 403_2 has at least an oxide having a channel-forming region. The semiconductor film 411_2, the gate electrode, the gate insulating film (not shown in Figure 16), and the source It includes an electrode and a drain electrode. Note that in scan line 407_2, an oxide semiconductor film The region superimposed with 411_2 functions as the gate electrode of transistor 403_2. In line 409, the region that overlaps with the oxide semiconductor film 411_2 is transistor 403_2 It functions as a source electrode. In the conductive film 413_2, the oxide semiconductor film 411_2 and The superimposed region functions as the drain electrode of transistor 403_2. Conductive film 413_ 2 and the pixel electrode 421_2 are connected at the aperture 417_2.

[0201] The retaining capacity 405_2 is similar to the retaining capacity 405_1, and is provided with a conductive film in the opening 423. It is electrically connected to the capacitance line 415 through 425. The retaining capacitance 405_2 is oxide A semiconductor oxide film 419_2 formed from a semiconductor, a pixel electrode 421_2, and a dielectric film It is composed of an insulating film (not shown in Figure 16) included in transistor 403_2. The oxide semiconductor film 419_2, the pixel electrode 421_2, and the dielectric film each have light-transmitting properties. Therefore, the holding capacity 405_2 is translucent.

[0202] Note that transistors 403_1 and 403_2, and the retaining capacitance 405_ The cross-sectional structures of transistor 103 and retaining capacitance 405_2 are shown in Figure 5, respectively. Since the capacitance is the same as 105, it will be omitted here. Also, transistor 403_1 and The transistor 403_2, and the holding capacity 405_1 and holding capacity 405_2 are transistors The symbols added to explain the sta 103 and the holding capacity 105 can be referred to as appropriate.

[0203] In the top surface shape, a capacitance line is provided between two adjacent pixels, and each pixel contains By connecting the holding capacity and the corresponding capacity lines, it is possible to reduce the number of capacity lines. As a result, it is possible to further increase the aperture ratio of the pixels compared to a structure in which capacitance lines are provided for each pixel. It is Noh.

[0204] <Example 7> In a semiconductor device according to one aspect of the present invention, the shape of the transistor provided in the pixel is The transistor shape is not limited to the examples shown above and can be changed as appropriate. In a transistor, the source electrode included in the signal line 109 is U-shaped (C-shaped, U-shaped) A transistor having a shape (either U-shaped or horseshoe-shaped) and a conductive film surrounding the drain electrode. This is also good. By using this shape, even if the area of ​​the transistor is small, sufficient channels can be achieved. This makes it possible to secure the width, and the drain current (on-current) that flows when the transistor conducts is secured. It becomes possible to increase the amount of (also called flow).

[0205] <Variation 8> In the modified example described above, pixels 101, 401_1, and 401_2, The oxide semiconductor film 111 includes a region that functions as both a gate insulating film 127 and a source electrode. The area located between the wire 109 and the conductive film 113, which includes a region that functions as a drain electrode. A transistor was used, but instead, the oxide semiconductor film 111 functions as the source electrode. A signal line 109 including a region and a conductive film 113 including a region that functions as a drain electrode A transistor located between the insulating films 129 can be used.

[0206] <Variation 9> In the modified example described above, pixels 101, 401_1, and 401_2, Although transistor 103 was shown as a channel-etch type transistor, instead By providing a channel protection film, a channel protection transistor can be used. The surface of the oxide semiconductor film 111 is used in the process of forming the signal line 109 and the conductive film 113. Without exposure to etchants or etching gases, between the oxide semiconductor film 111 and the channel protection film The impurities can be reduced. As a result, the source electrode and drain electrode of transistor 103 It is possible to reduce the leakage current flowing between them.

[0207] <Variation 10> In the modified example described above, pixels 101, 401_1, and 401_2, As transistor 103, a transistor with one gate electrode was shown, but instead A transistor having two opposing gate electrodes separated by an oxide semiconductor film 111 ( A dual-gate transistor can be used.

[0208] The dual-gate transistor is the insulating film of transistor 103 described in this embodiment. 129 has a conductive film (also called a back gate electrode). This conductive film is at least Both overlap with the channel formation region of the oxide semiconductor film 111. For example, the conductive film is channel Signal line 10 including a region that functions as the source electrode of the transistor in the length direction The shape can be made shorter than the width between 9 and the conductive film 113 which functions as a drain electrode. This is possible by placing the conductive film in a position that overlaps with the channel formation region of the oxide semiconductor film 111. Therefore, the potential of the conductive film shall be set to the lowest potential of the video signal input to signal line 109. This is preferable. As a result, on the surface of the oxide semiconductor film 111 facing the conductive film, It is possible to control the current flowing between the drain electrode and the transistor. Variations in electrical characteristics can be reduced. Furthermore, by providing this conductive film, the surrounding This reduces the effect of changes in the electric field on the oxide semiconductor film 111, thereby improving the reliability of the transistor 103. It can improve.

[0209] The conductive film is made of the same material and method as the scanning line 107, signal line 109, pixel electrode 121, etc. It can be formed by law. Furthermore, the conductive film is formed in the process of forming the pixel electrode 121. It can be formed using this. Therefore, as one electrode of the holding capacitance, a transistor By using a semiconductor film formed by the same formation process as the oxide semiconductor contained in, the aperture ratio can be increased. It is possible to fabricate semiconductor devices with increased holding capacity while simultaneously improving the charge capacity. Furthermore, by increasing the aperture ratio, it is possible to obtain a semiconductor device with excellent display quality.

[0210] Furthermore, the transistors within the pixels are made of oxide semiconductors, and the transistors The oxide semiconductor film contained in the zista has reduced oxygen vacancies and low levels of impurities such as hydrogen and nitrogen. By using a reduced oxide semiconductor film, a semiconductor device with good electrical properties can be obtained. Cut.

[0211] The configurations shown in this embodiment may be combined with the configurations shown in other embodiments as appropriate. It can be used.

[0212] (Embodiment 2) In this embodiment, the transistors included in the semiconductor device described in the above embodiment are used. Furthermore, regarding retention capacity, one embodiment applicable to an oxide semiconductor film, which is a semiconductor film, will be described. do.

[0213] The above oxide semiconductor films include amorphous oxide semiconductors, single-crystal oxide semiconductors, and polycrystalline oxides. In addition to semiconductors, there are oxide semiconductors that have a crystalline portion (C Axis Aligned Crystal Composed of stalline oxide semiconductor (CAAC-OS). It is preferable that this be done.

[0214] CAAC-OS film is one of the oxide semiconductor films having multiple crystalline regions, and most The crystalline portion is small enough to fit within a cube with sides less than 100 nm. Therefore, CAAC- The crystalline portion contained in the OS film is a cube with sides of less than 10 nm, less than 5 nm, or less than 3 nm. This also includes cases where the size fits within the structure. CAAC-OS films are smaller than microcrystalline oxide semiconductor films. It is characterized by a low defect level density. A detailed explanation of CAAC-OS films follows. cormorant.

[0215] CAAC-OS film is examined using a transmission electron microscope (TEM). When observed with a tron ​​microscope, a clear boundary between crystalline parts is observed, i.e. The grain boundaries (also called crystal grain boundaries) cannot be identified. Therefore, C AAC-OS films are less susceptible to the decrease in electron mobility caused by grain boundaries.

[0216] The CAAC-OS film was observed by TEM from a direction roughly parallel to the sample surface (cross-sectional TEM view). (Inference) It can be confirmed that in the crystalline part, metal atoms are arranged in layers. Each of these layers has a concave surface on the surface (also called the surface to be formed) or upper surface that forms the CAAC-OS film. The shape reflects a convexity and is arranged parallel to the surface or top surface of the CAAC-OS film to be formed.

[0217] On the other hand, the CAAC-OS film was observed by TEM from a direction roughly perpendicular to the sample surface (plane T). EM observation reveals that in the crystalline region, metal atoms are arranged in a triangular or hexagonal shape. This can be confirmed. However, no regularity is observed in the arrangement of metal atoms between different crystalline regions. do not have.

[0218] Cross-sectional TEM observation and planar TEM observation revealed that the crystalline portion of the CAAC-OS film exhibits orientation. It can be seen that this is the case.

[0219] X-ray diffraction (XRD) of CAAC-OS film When structural analysis is performed using the instrument, for example, CAAC-OS having InGaZnO4 crystals is found. Out-of-plane analysis of the film showed a peak at a diffraction angle (2θ) of around 31°. This peak may appear. This peak is attributed to the (009) plane of the InGaZnO4 crystal. Therefore, the crystals of the CAAC-OS film have c-axis orientation, and the c-axis is on the surface to be formed or on the upper surface. It can be confirmed that it is oriented in a roughly vertical direction.

[0220] On the other hand, in the CAAC-OS film, X-rays are incident from a direction approximately perpendicular to the c-axis in an in-p In analysis using the lane method, a peak may appear when 2θ is around 56°. This is attributed to the (110) plane of the InGaZnO4 crystal. For a crystalline semiconductor film, fix 2θ to approximately 56° and use the normal vector of the sample surface as the axis (φ axis). When the analysis (φ scan) is performed while rotating the sample, a crystal plane equivalent to the (110) plane is found. Six peaks attributable to this are observed. In contrast, in the case of the CAAC-OS film, 2θ Even when fixed at approximately 56° and scanned using the φ scan function, no clear peak appears.

[0221] From the above, it can be concluded that in CAAC-OS films, the orientation of the a-axis and b-axis between different crystalline regions is Although irregular, it has c-axis orientation, and the c-axis is parallel to the normal vector of the formed surface or the upper surface. It can be seen that it is oriented in a specific direction. Therefore, the layered structure confirmed by the aforementioned cross-sectional TEM observation is Each layer of arranged metal atoms is a plane parallel to the ab-plane of the crystal.

[0222] Furthermore, the crystalline portion is formed when the CAAC-OS film is deposited, or during crystallization treatments such as heat treatment. It is formed when the process is carried out. As mentioned above, the c-axis of the crystal is aligned with the surface on which the CAAC-OS film is formed. Or it is oriented in a direction parallel to the normal vector of the upper surface. Therefore, for example, the CAAC-OS film When the shape is altered by etching or other means, the c-axis of the crystal becomes the target area for CAAC-OS film formation. The normal vector may not be parallel to the normal vector of the face or top surface.

[0223] Furthermore, the degree of crystallinity in the CAAC-OS film does not need to be uniform. For example, CAAC-OS When the crystalline portion of the film is formed by crystal growth from near the upper surface of the CAAC-OS film, The region near the surface may have a higher degree of crystallinity than the region near the surface being formed. Also, CA When impurities are added to an AC-OS film, the degree of crystallinity in the region where the impurities are added changes, and Regions with varying degrees of crystallinity may also be formed.

[0224] Furthermore, the out-of-plane CAAC-OS film having InGaZnO4 crystals Analysis using this method revealed that in addition to the peak near 2θ = 31°, there is also a peak near 2θ = 36°. In some cases, this may occur. Peaks near 2θ of 36° indicate c-axis orientation in a portion of the CAAC-OS film. This indicates the presence of crystals that do not possess properties. The CAAC-OS film has a 2θ of approximately 31°. It is preferable that a peak is shown and that no peak is shown near 36° for 2θ.

[0225] There are three possible methods for forming CAAC-OS.

[0226] The first method involves forming an oxide semiconductor film at a film formation temperature of 100°C to 450°C. As a result, the c-axis of the crystalline portion contained in the oxide semiconductor film is the normal vector of the formed surface or the surface This method forms crystal regions aligned in a direction parallel to the normal vector.

[0227] The second method involves depositing an oxide semiconductor film to a thin thickness, followed by heating at a temperature between 200°C and 700°C. By performing a heat treatment, the c-axis of the crystalline portion contained in the oxide semiconductor film becomes the normal vector to the surface to be formed. This method forms crystal regions aligned in a direction parallel to the normal vector of the tor or surface.

[0228] The third method involves depositing a thin first layer of oxide semiconductor film, followed by heating at 200°C or above 700°C. By performing a heat treatment below ℃ and then depositing a second oxide semiconductor film, the oxide semiconductor The c-axis of the crystalline portion contained in the conductive film is parallel to the normal vector of the surface being formed or the normal vector of the surface. This is a method for forming crystal regions aligned in the direction of grain.

[0229] Transistors with CAAC-OS applied to oxide semiconductor films are resistant to visible light and ultraviolet light irradiation. The variation in electrical properties is small. Therefore, applying CAAC-OS to oxide semiconductor films results in a small change in performance. The generator has good reliability.

[0230] Furthermore, CAAC-OS uses polycrystalline oxide semiconductor sputtering targets. It is preferable to deposit the film by sputtering. The sputtering target When ions collide with the sputtering target, the crystalline region contained within the sputtering target is on the ab plane. The sputtering particles are cleaved and have a flat or pellet-shaped surface parallel to the ab plane. This can cause peeling. In this case, the flat or pellet-shaped sputtering particles may By maintaining its crystalline state, CAAC-OS can be deposited on the film-forming surface. Cut.

[0231] Furthermore, it is preferable to apply the following conditions for forming the CAAC-OS film.

[0232] By reducing the inclusion of impurities during film formation, it is possible to suppress the disruption of the crystalline state due to impurities. For example, the concentration of impurities present in the deposition chamber (such as hydrogen, water, carbon dioxide, and nitrogen). It should be reduced. Also, the concentration of impurities in the film-forming gas should be reduced. Specifically, the dew point A film-forming gas with a temperature of -80°C or lower, preferably -100°C or lower, is used.

[0233] Furthermore, by increasing the heating temperature of the film-forming surface during film formation (e.g., substrate heating temperature), the film-forming surface After reaching a certain temperature, migration of sputtering particles occurs. Specifically, the temperature of the film-deposited surface... The film is formed at a temperature of 100°C to 740°C, preferably 150°C to 500°C. By increasing the temperature of the film-forming surface during film formation, the plate-shaped or pellet-shaped sputtering particles are produced. When it reaches the film-depositing surface, migration occurs on that surface, resulting in sputtering. The flat side of the particles adheres to the film-forming surface.

[0234] Furthermore, by increasing the oxygen content in the deposition gas and optimizing the power, plasma damage during film deposition can be reduced. It is preferable to reduce the amount of oxygen. The oxygen content in the film-forming gas is 30% by volume or more, preferably 100%. This is expressed as a percentage by volume.

[0235] As an example of a target for sputtering, an In-Ga-Zn-O compound target is used. The details are as follows.

[0236] InO X powder, GaO Y Powder and ZnO Z The powder is mixed in a predetermined number of moles and then subjected to pressure treatment. By heat treatment at temperatures between 1000°C and 1500°C, polycrystalline In-Ga - A Zn-based metal oxide target is used. Note that this pressurized treatment is performed while cooling (or allowing to cool). You can proceed from here, or you can proceed while heating. Note that X, Y, and Z are any positive numbers. Here, the given molar ratio is, for example, InO X powder, GaO Y Powder and ZnO Z powder However, the ratios are 2:2:1, 8:4:3, 3:1:1, 1:1:1, 4:2:3, or 3:1:2. The type of powder and the molar ratio in which they are mixed will be determined for the sputtering process. You can change it as needed by getting it.

[0237] Furthermore, the oxide semiconductor film may have a structure in which multiple oxide semiconductor films are stacked. For example, The oxide semiconductor film is constructed as a stack of a first oxide semiconductor film and a second oxide semiconductor film, and the first Metal oxides with different atomic ratios may be used for the oxide semiconductor film and the second oxide semiconductor film. For example, the first oxide semiconductor film contains an oxide containing two types of metals, and an oxide containing three types of metals. Using one of four metal oxides, the first oxide is applied to the second oxide semiconductor film. A semiconductor film containing two different metals, an oxide containing three different metals, and four different metals. Oxides containing may also be used.

[0238] The oxide semiconductor film has a two-layer structure, consisting of a first oxide semiconductor film and a second oxide semiconductor film. The elements may be the same, but the atomic ratio of the two may be different. For example, the first oxide semiconductor film The atomic ratio is set to In:Ga:Zn = 3:1:2, and the atomic ratio of the second oxide semiconductor film is set to In The ratio of :Ga:Zn may be set to 1:1:1. Alternatively, the atomic ratio of the first oxide semiconductor film may be set to In Let :Ga:Zn=2:1:3, and set the atomic ratio of the second oxide semiconductor film to In:Ga:Zn= A ratio of 1:3:2 is also acceptable. Note that the atomic ratio of each oxide semiconductor film is set to the above-mentioned atomic ratio as an error. Includes a variation of plus or minus 20% in numerical ratios.

[0239] At this time, of the first oxide semiconductor film and the second oxide semiconductor film, the side closer to the terminal electrode ( It is preferable to set the atomic ratio of In to Ga in the oxide semiconductor film on the channel side to In ≥ Ga. The atomic ratio of In to Ga in the oxide semiconductor film on the side far from the gate electrode (back channel side) may be In < Ga. With these laminated structures, a transistor with high field-effect mobility can be fabricated. On the other hand, the atomic ratio of In to Ga in the oxide semiconductor film on the side close to the gate electrode (channel side) is set to In < Ga, and the atomic ratio of In to Ga in the oxide semiconductor film on the back channel side is set to In ≧ Ga, whereby the variation amount of the threshold voltage due to the change over time of the transistor and the reliability test can be reduced.

[0240] The first oxide semiconductor film having an atomic ratio of In:Ga:Zn = 1:3:2 can be formed by a sputtering method using an oxide target having an atomic ratio of In:Ga:Zn = 1:3:2. The substrate temperature is set to room temperature, and it can be formed using argon or a mixed gas of argon and oxygen as the sputtering gas. The second oxide semiconductor film having an atomic ratio of In:Ga:Zn = 3:1:2 can be formed in the same manner as the first oxide semiconductor film using an oxide target having an atomic ratio of In:Ga:Zn = 3:1:2.

[0241] Also, the oxide semiconductor film may have a three-layer structure, and the constituent elements of the first to third oxide semiconductor films may be the same, and the atomic ratios thereof may be different. The configuration in which the oxide semiconductor film has a three-layer structure will be described using FIG. 17.

[0242] The transistor 297 shown in FIG. 17 has a first oxide semiconductor film 299a, a second oxide semiconductor film 299b, and a third oxide semiconductor film 299c laminated in this order from the gate insulating film 127 side. The first oxide semiconductor film 299a and the third oxide semiconductor film 299c are configured ​​​​​The material to be used is InM1 x Zn y O z (x ≧ 1, y > 1, z > 0, M1 = Ga, Hf, etc.)<​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Therefore, the silicon and carbon concentrations contained in each oxide semiconductor film are 3 × 10 18 / c m 3 The following is preferably 3 × 10 17 / cm 3 The following applies. In particular, the second oxide semiconductor film 2 To prevent a large amount of Group 14 elements from being mixed into 99b, the first oxide semiconductor film 299a and the third The oxide semiconductor film 299c sandwiches the second oxide semiconductor film 299b, which serves as the carrier path. It is preferable to have a configuration that surrounds or surrounds the first oxide semiconductor film 299a and the third Oxide semiconductor film 299c is a second oxide semiconductor film in which Group 14 elements such as silicon and carbon are present. It can also be called a barrier film that prevents contamination of 299b.

[0246] For example, if the atomic ratio of the first oxide semiconductor film 299a is In:Ga:Zn=1:3:2 Furthermore, the atomic ratio of the second oxide semiconductor film 299b is set to In:Ga:Zn=3:1:2, The atomic ratio of the oxide semiconductor film 299c in step 3 may be set to In:Ga:Zn = 1:1:1. Furthermore, the third oxide semiconductor film 299c has an atomic ratio of In:Ga:Zn=1:1:1. It can be formed by a sputtering method using an oxide target.

[0247] Alternatively, the first oxide semiconductor film 299a has an atomic ratio of In:Ga:Zn=1:3:2 The oxide semiconductor film is defined as follows, and the second oxide semiconductor film 299b has an atomic ratio of In:Ga: The oxide semiconductor film is such that Zn=1:1:1 or In:Ga:Zn=1:3:2, and the third The oxide semiconductor film 299c has an atomic ratio of In:Ga:Zn = 1:3:2. It may also be a three-layered structure with a body membrane.

[0248] The constituent elements of the first oxide semiconductor film 299a to the third oxide semiconductor film 299c are the same. Therefore, the second oxide semiconductor film 299b has an interface with the first oxide semiconductor film 299a. There are few defect levels (trap levels) in this case. More specifically, the defect levels (trap levels) are , the defect level at the interface between the gate insulating film 127 and the first oxide semiconductor film 299a is greater than There are few. Therefore, as described above, the oxide semiconductor film is stacked, which is why transistors This can reduce the amount of fluctuation in threshold voltage due to changes over time and reliability tests.

[0249] Furthermore, the conduction band of the first oxide semiconductor film 299a and the conduction band of the third oxide semiconductor film 299c Compared to the conduction band, the conduction band of the second oxide semiconductor film 299b is the deepest from the vacuum level. The materials for the first, second, and third oxide semiconductor films are appropriately selected to form a well-shaped structure. This makes it possible to increase the field-effect mobility of the transistor, and also the transistor This can reduce the amount of fluctuation in threshold voltage due to changes in the stanium over time and reliability testing.

[0250] Furthermore, the first oxide semiconductor film 299a to the third oxide semiconductor film 299c have crystalline properties. Different oxide semiconductors may be used. That is, single-crystal oxide semiconductors, polycrystalline oxide semiconductors, etc. A configuration may be used in which a conductor, an amorphous oxide semiconductor, and CAAC-OS are appropriately combined. Furthermore, any one of the first oxide semiconductor film 299a to the third oxide semiconductor film 299c Applying amorphous oxide semiconductors relieves internal and external stresses in the oxide semiconductor film. This reduces fluctuations in the electrical characteristics of transistors, and also improves the reliability of transistors over time. This can reduce the amount of fluctuation in the threshold voltage.

[0251] Furthermore, the second oxide semiconductor film 299b, which can at least become a channel formation region, is CAA It is preferable that it be C-OS. Also, the oxide semiconductor film on the back channel side, the form of this embodiment In this state, the third oxide semiconductor film 299c is an amorphous oxide semiconductor or CAAC-OS. It is preferable to have such a structure, which allows for testing of transistor changes over time and reliability. This can reduce the amount of fluctuation in the threshold voltage.

[0252] Furthermore, in a semiconductor device according to one aspect of the present invention, the transistor 103 is shown in Figure 17. When transistor 297 is applied, the oxide acts as one of the electrodes of the retention capacitance 105. The semiconductor film 119 is also the first oxide semiconductor film 299a to the third oxide semiconductor film 299c. It forms a layered structure.

[0253] In this case, the channel formation region of the transistor 297, which is the pixel switching element, is It can be said that the oxide semiconductor film 299b is 2. And in the retention capacity 105, the first The oxide semiconductor film 299a to the third oxide semiconductor film 299c have a holding capacity of 105. It can be said that it functions as an electrode.

[0254] In other words, in this configuration, the channel of the transistor, which is the switching element of the pixel The formation region is a surface on which an oxide semiconductor film, which functions as one of the electrodes for holding capacity, is provided. These are provided on different surfaces.

[0255] The configurations shown in this embodiment may be combined with the configurations shown in other embodiments as appropriate. It can be used.

[0256] (Embodiment 3) A semiconductor with a display function using the transistor and retaining capacitor shown as an example in the above embodiment. Conductive devices (also called display devices) can be manufactured. Furthermore, drivers including transistors can be manufactured. A part or all of the dynamic circuit is integrally formed on the same substrate as the pixel section to form a system-on-panel. This is possible. In this embodiment, the transistor shown as an example in the above embodiment is used. An example of a display device will be explained using diagrams.

[0257] In Figure 18(A), the pixel portion 902 provided on the first substrate 901 is surrounded by A sealing material 905 is provided and sealed by the second substrate 906. Figure 18(A In this case, the area is different from the area surrounded by the sealing material 905 on the first substrate 901. In the region, signal line chips formed of single-crystal or polycrystalline semiconductors on a separately prepared substrate are used. A drive circuit 903 and a scan line drive circuit 904 are implemented. Also, a signal line drive circuit 90 3. Various signals and potentials are supplied to the scan line drive circuit 904 or the pixel unit 902, FPC (Flexible printed circuit) 918a, FPC918b It is being supplied.

[0258] In Figures 18(B) and 18(C), the pixel portion 90 is provided on the first substrate 901. A sealing material 905 is provided so as to surround 2 and the scan line drive circuit 904. A second substrate 906 is provided on top of the pixel section 902 and the scan line driving circuit 904. The pixel section 902 and the scan line driving circuit 904 are connected to the first substrate 901 and the sealing material 905. The display element is sealed together with the second substrate 906. (Figures 18(B) and 1) In 8(C), the region surrounded by the sealing material 905 on the first substrate 901 and These are signals formed from single-crystal or polycrystalline semiconductors on a separately prepared substrate in different regions. The signal drive circuit 903 is implemented. In Figures 18(B) and 18(C), the signal Various signals are provided to the line drive circuit 903, the scan line drive circuit 904, or the pixel unit 902, and The potential is supplied from the FPC918.

[0259] Furthermore, in Figures 18(B) and 18(C), the signal line drive circuit 903 is formed separately. The example shown is mounted on the first substrate 901, but the configuration is not limited to this. The drive circuit may be formed and implemented separately, or it may be part of the signal line drive circuit or the scan line drive circuit. It is also acceptable to separately form and implement only a portion of it.

[0260] Furthermore, the method of connecting the separately formed drive circuit is not particularly limited, and COG(C (hip-on-glass) method, wire bonding method, or TAB (Tape) Automated bonding methods can be used. Figure 18(A) This is an example of implementing the signal line drive circuit 903 and the scan line drive circuit 904 using the COG method. Figure 18(B) shows an example of implementing the signal line drive circuit 903 using the COG method. C) is an example of implementing the signal line drive circuit 903 using the TAB method.

[0261] Furthermore, the display device includes a panel in which the display elements are sealed, and a control to the panel. This includes modules with ICs, including ra, mounted on them.

[0262] In this specification, "display device" refers to an image display device or a display device. Furthermore, it can function as a light source (including lighting devices) instead of a display device. , a module to which a connector, such as an FPC or TCP, is attached, to the TCP A module equipped with a printed circuit board, or a display element, is equipped with an IC (integrated circuit board) using the COG method. All modules in which the road is directly implemented are also included in the display device.

[0263] Furthermore, the pixel section 902 and the scanning line driving circuit 904 provided on the first substrate 901 are It has multiple transistors, and the transistors shown in the above embodiment can be applied. Cut.

[0264] Display elements used in display devices include liquid crystal elements (also called liquid crystal display elements) and light-emitting elements. A light-emitting element (also called a light-emitting display element) can be used. The light-emitting element is controlled by current or voltage. This category includes elements whose brightness is controlled by [something], specifically organic EL (Electroluminescent) This includes Luminescence elements, inorganic EL elements, etc. Also, electronic inks. Furthermore, display media in which the contrast changes due to electrical effects can also be applied. Figure 19 The following shows an example of a liquid crystal display device that uses liquid crystal elements as display elements.

[0265] Figures 19 and 20 are cross-sectional views between the dashed line X1 and X2 in Figure 18(B). In Figures 19 and 20, only a portion of the pixel structure is shown.

[0266] The display devices shown in Figures 19 and 20 are vertical electric field type liquid crystal display devices. It has a connecting terminal electrode 915 and a terminal electrode 916, and the connecting terminal electrode 915 and terminal The electrode 916 is electrically connected to the terminals of the FPC 918 via the anisotropic conductive material 919. It is being done.

[0267] The connecting terminal electrode 915 is formed from the same conductive film as the first electrode 930, and the terminal electrode 916 It is formed of the same conductive film as the source and drain electrodes of transistors 910 and 911. It is.

[0268] Furthermore, the pixel section 902 and the scanning line driving circuit 904 provided on the first substrate 901 are It has multiple transistors, and the transistor 910 included in the pixel section 902 and the scan line drive The transistor 911 included in circuit 904 is shown as an example. Transistors 910 and On the oxide semiconductor film contained in the lampistor 911, there is an insulating film 129 as shown in Embodiment 1, and an insulating film An insulating film 924 corresponding to the edge film 131 and insulating film 132 is provided. 23 is an insulating film that functions as a base layer.

[0269] In this embodiment, transistors 910 and 911 are defined as the above-described embodiment. Any of the transistors shown in the diagram can be applied. Also, the oxide semiconductor film 92 7. The retaining capacitance 926 is formed using the insulating film 924 and the first electrode 930. Oh, the oxide semiconductor film 927 has capacitance lines 929 and an opening formed in the gate insulating film 922. They are electrically connected via the electrode 928 that is formed. The capacitance line 929 is a transistor The scan line and the same conductive region that includes the region that functions as the gate electrode of transistors 910 and 911 It is formed from an electrolytic film. Note that, in this case, the holding capacity 926 is the configuration shown in Embodiment 1. The holding capacity is shown in the diagram, but the holding capacity of the configuration shown in other embodiments may be used as appropriate. It is possible.

[0270] Furthermore, in the transistor 911 included in the scan line drive circuit 904, as shown in Figure 19(A) The conductive film is located on the insulating film 924, in a position that overlaps with the channel formation region of the oxide semiconductor film. Figure 19(B) shows a structure in which 917 is provided. A region 951 is provided, and on the insulating film 951 is a channel formation region of the oxide semiconductor film. This shows a structure in which a conductive film 917 is provided in a position that overlaps with the other element.

[0271] The conductive film 917 can supply potential and is connected to the gate electrode of transistor 911. It functions in this way. In other words, transistor 911 is a dual-gate transistor. The conductive film 917 can be formed from the same conductive film as the first electrode 930. 917 is located in the channel length direction, and the source electrode and drain electrode of transistor 911 are connected. The shape can be shorter than the width between the poles.

[0272] The transistor 911 included in the scan line drive circuit 904 is provided with a conductive film 917. By doing so, the gate voltage at which on-current begins to flow at different drain voltages (rising gate voltage) The fluctuations of the (seat voltage) can be reduced. Also, transistor 911 has a conductive film 917 Because of the provision, in the region of the oxide semiconductor film on the conductive film 917 side, It is possible to control the current flowing between the source and drain electrodes of the TA911. Therefore, the variation in electrical characteristics between multiple transistors included in the scan line drive circuit 904 This can reduce the potential of the conductive film 917 in transistor 911. By setting the minimum potential of the scan line drive circuit 904 to the same potential, or a potential equivalent to that minimum potential, This makes it possible to reduce the threshold voltage fluctuation of transistor 911, thus improving reliability. It can be increased. Note that the lowest potential of the scan line drive circuit 904 is the scan line drive circuit 90 This refers to the lowest potential supplied when operating 4. For example, scan line drive The potential supplied when operating the motor circuit 104 is the potential of the source electrode of transistor 911. When used as a reference, it is the potential (Vss) of the source electrode.

[0273] In the transistor 911 included in the scan line drive circuit 904, the thickness of the insulating film 924 is If it is thin, the effect of the electric field from the conductive film 917 applied to the oxide semiconductor film will cause the transistor to... Variations in the electrical characteristics of 911 may occur. Therefore, as shown in Figure 19(B), insulating film 95 By providing 1, the effect of the electric field can be controlled, and the transistor 911 Electrical characteristics can be improved.

[0274] The insulating film 951 can be made of a material applicable to the insulating film 924. As 951, an organic insulating film can be used. The organic insulating film can be photosensitive, non-photosensitive, etc. Examples include photosensitive organic resins, such as acrylic resins, benzocyclobutene resins, and epoxy resins. Xylamine resin or siloxane-based resin can be used. Polyamide can be used. Furthermore, the method for forming the organic insulating film is not particularly limited. Furthermore, the appropriate method can be selected depending on the materials used. For example, spin coating, dipping, and spraying. Coating, droplet ejection (inkjet method), screen printing, offset printing, etc. are applied. It is possible.

[0275] Furthermore, the conductive film 917 also has the function of shielding against external electric fields. In other words, when an external electric field is present inside... A function to prevent it from affecting (circuit parts including transistors) (especially electrostatic shielding against static electricity). It also has a shielding function. Due to the shielding function of the conductive film 917, the transistor 911 is protected from static electricity, etc. This suppresses fluctuations in the electrical characteristics of the transistor due to the influence of an external electric field, thus improving reliability. It can improve.

[0276] Note that Figure 19 shows the transistors included in the scan line drive circuit, but the signal The transistors included in the line drive circuit are dual-gate transistors, similar to the 911 transistor. It can be made into a zista. The transistor included in the signal line drive circuit is a dual gate transistor. By using a transistor, the transistor achieves the same effect as transistor 911. .

[0277] As described above, a semiconductor device (display device) according to one aspect of the present invention is a highly reliable semiconductor device. be.

[0278] Next, we will explain a structure that differs from the vertical electric field type liquid crystal display device shown in Figure 19. Next, we will explain the transverse electric field type liquid crystal display device using Figure 20. Figure 20 shows the transverse electric field type One example is the LCD in FFS (Fringe Field Switching) mode. It is a display device.

[0279] In the liquid crystal display device shown in Figure 20, the connection terminal electrode 915 is the same as the first electrode 940. Formed from the same material and process, terminal electrode 916 is the source of transistors 910 and 911. The electrodes and drain electrodes are formed from the same material and using the same process.

[0280] Furthermore, the liquid crystal element 943 has a first electrode 940 and a second electrode formed on the insulating film 924. This includes 941 and the liquid crystal 908. Note that the liquid crystal element 943 has the holding capacity shown in Embodiment 1. It can have a structure similar to that of 105. The first electrode 940 is the first electrode shown in Figure 19. The materials shown in 930 can be used as appropriate. Furthermore, the first electrode 940 has a planar shape. They are comb-shaped, step-shaped, ladder-shaped, etc. The second electrode 941 functions as a common electrode, and in practice It can be formed in the same manner as the oxide semiconductor film 119 shown in state 1. The first electrode 940 and An insulating film 924 is provided between the second electrodes 941.

[0281] The second electrode 941 is connected to the common wiring 946 via electrode 945. 45 is the same as the source and drain electrodes of transistors 910 and 911. It is formed from a conductive film. The common wiring 946 is connected to transistors 910 and 911. It is formed using the same material and process as the gate electrode. Here, it is referred to as the liquid crystal element 943. Although the explanation was given using the holding capacity shown in Embodiment 1, other embodiments may be shown as appropriate. Capacity can be used.

[0282] Note that the transistor 91 is included in the scan line driving circuit 904 of the liquid crystal display device shown in Figure 20. In 1, similar to Figure 19(B), an insulating film 951 is placed between the conductive film 917 and the insulating film 924. It can be established.

[0283] Here, a transistor included in a semiconductor device (display device) according to one aspect of the present invention For example, in multiple transistors included in the scan line driving circuit 904, the gate electrode A wiring including a source electrode or drain electrode is electrically connected by a conductive film. The structure will be explained. Figure 21(A) shows a top view of the structure, and Figure 21(B) shows a figure The cross-sectional view between the dashed lines Y1-Y2 and Z1-Z2 of 21(A) is shown.

[0284] From Figure 21(A), the wiring 950 including the gate electrode of transistor 911, and the transistor The wiring 952, including the source electrode of the starter 911, is connected to the guides provided in the openings 954 and 956. It is in contact with the film 958.

[0285] As shown in Figure 21(B), the cross-sectional structure shows that an insulating film 923 is provided on the substrate 901, providing insulation. Wiring 950 is provided on the film 923, and gate insulation is provided on the wiring 950 and the insulating film 923. An edge film 922 is provided, and wiring 952 is provided on the gate insulating film 922. An insulating film 924 is provided on the gate insulating film 922 and the wiring 952. And, one point In the region of the dashed line Y1-Y2, the gate insulating film 922 and insulating film 924 reach the wiring 950. An opening 954 is provided, and in the region of the dashed line Z1-Z2, the insulating film 924 An opening 956 is provided that reaches the wiring 952. And on the insulating film 924 and the opening 95 A conductive film 958 is provided on both 4 and the opening 956.

[0286] From the above, wiring 950 including the gate electrode and wiring 95 including the source electrode or drain electrode 2 and 3 are electrically connected by a conductive film 958.

[0287] The conductive film 958 is formed using the same process as the formation of the conductive film 917 of the transistor 911. This can be done. In addition, in the multiple transistors included in the scan line drive circuit 904, The wiring including the source electrode and the wiring including the source electrode or drain electrode are electrically connected by a conductive film. If the structure is to be connected, a conductive film should be applied in a position that overlaps with the channel formation region of the transistor. It is preferable to have a configuration that does not include this feature.

[0288] Openings 954 and 956 can be formed simultaneously. Details are as follows. An insulating film to be processed into a gate insulating film 922 is formed on the wiring 950, and wiring is placed on the insulating film. 952 is formed, and an insulating film that will be processed into an insulating film 924 is formed on the wiring 952. Then, A mask is formed on the insulating film 924, and by processing using the mask, an opening 954 is formed. And an opening 956 can be formed. A resist mask is used as the mask. This can be done. Dry etching can be used for this process. Wiring 95 By forming 0 with a metal material, etching occurs in the wiring 950 and gate insulating film 922. Because the etching selectivity ratio can be increased, this dry etching method allows for the etching of the aperture 954 and The opening 956 can be formed all at once.

[0289] The transistor 910 provided in the pixel section 902 is electrically connected to the display element.

[0290] The liquid crystal element 913, which is a display element, has a first electrode 930, a second electrode 931, and liquid crystal 9 Includes 08. Alignment films 932 and 933 are provided so as to sandwich the liquid crystal 908. Furthermore, the second electrode 931 is provided on the second substrate 906 side, and the first electrode 930 and the second electrode The electrode 931 is configured to overlap with the liquid crystal 908. The liquid crystal element 913 is in its actual form. You can refer to the liquid crystal element 108 described in Form 1. The first electrode 930 is in the form The second electrode 931 corresponds to the pixel electrode 121 described in Embodiment 1, and the second electrode 931 corresponds to the one described in Embodiment 1. The counter electrode 154 corresponds to the liquid crystal 908, and the liquid crystal 908 corresponds to the liquid crystal 160 described in Embodiment 1. The orientation film 932 corresponds to the orientation film 158 described in Embodiment 1, and the orientation film 933 is in Embodiment This corresponds to the orientation film 156 described in 1.

[0291] The first electrode 930 and the second electrode 931 (pixel electrode, common electrode) apply voltage to the display element. Also called poles or counter electrodes.) In this case, the direction of the light extracted, the location where the electrodes are installed, The transparency or reflectivity can be selected depending on the pattern structure of the electrodes.

[0292] The first electrode 930 and the second electrode 931 are paired with the pixel electrode 121 shown in Embodiment 1. The same material as that used for the directional electrode 154 can be used as appropriate.

[0293] Furthermore, the spacer 935 is a columnar space obtained by selectively etching the insulating film. This is a control of the distance (cell gap) between the first electrode 930 and the second electrode 931. It is provided for this purpose. A spherical spacer may also be used.

[0294] The first substrate 901 and the second substrate 906 are fixed together by a sealing material 905. Material 905 can be made of organic resins such as thermosetting resins and photocuring resins. The sealing material 905 is in contact with the insulating film 924.

[0295] Furthermore, in a semiconductor device (display device) according to one aspect of the present invention, a light-shielding film (black matrix Optical components (optical substrates), such as polarizing members, phase difference members, and anti-reflective members, may be used as appropriate. Provide a light source. For example, circular polarization using a polarizing substrate and a phase difference substrate may be used. Backlights, sidelights, etc., may also be used.

[0296] Furthermore, transistors are susceptible to damage from static electricity, etc., so a protective circuit is needed to protect the drive circuit. It is preferable to provide a path. The protection circuit is preferably constructed using nonlinear elements.

[0297] Figure 22 shows the display device shown in Figures 18 and 19, with a second provided on the substrate 906. A common connection portion (pad portion) for electrically connecting to the electrode 931 is formed on the substrate 901. Here is an example.

[0298] The common connection point overlaps with the sealing material 925 used to bond the circuit board 901 and the circuit board 906. It is positioned and electrically connects with the second electrode 931 via conductive particles contained in the sealing material 925. It is connected to the following: Alternatively, it is connected to a common area that does not overlap with the sealing material 925 (except for the pixel area). A connecting section is provided, and a paste containing conductive particles is applied to the common connection section, overlapping with the sealing material 925. A separate electrode may be provided and electrically connected to the second electrode 931.

[0299] Figure 22(A) is a cross-sectional view of the common connection section, and the IJ in the top view shown in Figure 22(B) is opposite to the It is correct.

[0300] The common potential line 975 is provided on the gate insulating film 922, and the transistor 9 shown in Figure 22 The 10 source electrodes 971 or drain electrodes 973 are manufactured using the same materials and processes.

[0301] Furthermore, the common potential line 975 is covered with an insulating film 924, and the insulating film 924 is covered with the common potential line 97 It has multiple openings in a position that overlaps with 5. These openings are for the source power of transistor 910. A contact hole connecting either electrode 971 or drain electrode 973 to the first electrode 930. It is manufactured using the same process as the ru.

[0302] Furthermore, the common potential line 975 and the common electrode 977 are connected at the opening. Common electrode 977 It is provided on the insulating film 924 and is the same as the connection terminal electrode 915 and the first electrode 930 of the pixel part. It is made from the same materials and using the same process.

[0303] In this way, a common connection section is created by making it the same as the manufacturing process for the switching element of the pixel section 902. It can be manufactured.

[0304] The common electrode 977 is an electrode that comes into contact with conductive particles contained in the sealing material, and is located on the substrate 906. An electrical connection is made with the second electrode 931.

[0305] Also, as shown in Figure 22(C), the common potential line 985 is connected to the gate of transistor 910. It may be formed using the same material and process as the electrodes.

[0306] In the common connection shown in Figure 22(C), the common potential line 985 is connected to the gate insulating film 922 and The gate insulating film 922 and insulating film 924 are provided in the lower layer of the insulating film 924, and the gate insulating film 922 and insulating film 924 share a common potential line. It has multiple openings in a position that overlaps with 985. These openings are the source electrodes of transistor 910. A contact hole connecting either 971 or the drain electrode 973 to the first electrode 930. After etching the insulating film 924 in the same process, the gate insulating film 922 is further selectively etched. It is formed by tweaking.

[0307] Furthermore, the common potential line 985 and the common electrode 987 are connected at the opening. Common electrode 987 It is provided on the insulating film 924 and is the same as the connection terminal electrode 915 and the first electrode 930 of the pixel part. It is made from the same materials and using the same process.

[0308] Based on the above, the oxide semiconductor film contained in the transistor is used as one of the electrodes for holding capacitance. By using an oxide semiconductor film formed in the same formation process, the aperture ratio can be increased while the charge capacitance is increased. A semiconductor device with a large retention capacity can be fabricated. For example, in this embodiment... In semiconductor devices, when the pixel density is 300 ppi or more, the aperture ratio of the pixels More than 50%, and furthermore, more than 55% of the pixel aperture ratio, and furthermore, more than 60% of the pixel aperture ratio This can be achieved. Furthermore, by increasing the aperture ratio, semiconductor devices with superior display quality can be produced. It can be obtained.

[0309] Furthermore, the oxide semiconductor film contained in the transistor has reduced oxygen vacancies, and hydrogen, nitrogen, etc. Because the impurities are reduced, a semiconductor device according to one aspect of the present invention has good electrical properties. It is a semiconductor device that possesses properties.

[0310] The configurations shown in this embodiment may be combined with the configurations shown in other embodiments as appropriate. It can be used.

[0311] (Embodiment 4) One aspect of the present invention is a semiconductor device that can be applied to various electronic devices (including amusement machines). This is possible. Examples of electronic devices include television equipment (televisions or television receivers). Also known as: monitors for computers, digital cameras, digital video cameras, Digital photo frames, mobile phones, portable game consoles, personal digital assistants, audio playback devices, Examples include amusement machines (pachinko machines, slot machines, etc.) and game cabinets. An example is shown in Figure 23.

[0312] Figure 23(A) shows table 9000 having a display unit. Table 9000 is The housing 9001 incorporates a display unit 9003, and the display unit 9003 displays video. It is possible to do so. Furthermore, the configuration in which the housing 9001 is supported by four legs 9002 is... It is shown. Furthermore, the casing 9001 has a power cord 9005 for power supply.

[0313] The semiconductor device shown in any of the above embodiments can be used in the display unit 9003. Yes. Therefore, the display quality of the display unit 9003 can be improved.

[0314] The display unit 9003 has a touch input function, and the display unit 9003 of the table 9000 By touching the displayed button 9004 with your finger, you can operate the screen or input information. This allows for communication with or control of other home appliances, It may also be used as a control device to control other home appliances by operating a surface. For example, Image By using a semiconductor device with sensor functionality, the display unit 9003 can be given a touch input function. It is possible.

[0315] Furthermore, a hinge provided on the housing 9001 allows the screen of the display unit 9003 to be positioned relative to the floor. It can be stood upright and used as a television set. In a small room, Installing a large-screen television set reduces the available space, but a table If the display unit is built into the unit, the space in the room can be used more effectively.

[0316] Figure 23(B) shows the television system 9100. The housing 9101 incorporates a display unit 9103, and the display unit 9103 displays images. It is possible to demonstrate this. Here, the stand 9105 supports the housing 9101. This shows the configuration.

[0317] The television unit 9100 is operated using the control switches on the housing 9101, or a separate unit. This can be done using the remote control unit 9110. The remote control unit 9110 has an operating key -9109 allows you to control the channel and volume, and the display unit 9103 displays the information. The video can be controlled. Furthermore, the remote control unit 9110 can control the remote control. A display unit 9107 may be provided to display information output from the unit 9110.

[0318] The television system 9100 shown in Figure 23(B) includes a receiver, a modem, and other components. The television equipment 9100 can receive general television broadcasts using its receiver. Furthermore, by connecting to a wired or wireless communication network via a modem, One-way (sender to receiver) or two-way (sender and receiver, or between receivers, etc.) It is also possible to communicate information.

[0319] The semiconductor device shown in any of the above embodiments is used in the display units 9103 and 9107. This is possible. Therefore, the display quality of television equipment can be improved.

[0320] Figure 23(C) shows the computer 9200, consisting of the main unit 9201, the casing 9202, and the display unit 9 203, Keyboard 9204, External connection port 9205, Pointing device 920 Includes 6, etc.

[0321] The semiconductor device shown in any of the above embodiments can be used in the display unit 9203. Yes. Therefore, it is possible to improve the display quality of the computer 9200.

[0322] The display unit 9003 has a touch input function, and the display unit 9003 of the table 9000 By touching the displayed buttons with your finger, you can operate the screen and input information. Furthermore, by enabling communication with or control of other home appliances, screen operation becomes possible. It can also be used as a control device to control other home appliances. For example, an image sensor device. By using a semiconductor device with the necessary capabilities, the display unit 9003 can be given a touch input function. Cut.

[0323] Furthermore, a hinge provided on the housing 9001 allows the screen of the display unit 9003 to be positioned relative to the floor. It can be stood upright and used as a television set. In a small room, Installing a large-screen television set reduces the available space, but a table If the display unit is built into the unit, the space in the room can be used more effectively.

[0324] Figures 24(A) and 24(B) show a foldable tablet device. ) is in an open state, and the tablet terminal consists of a housing 9630, a display unit 9631a, and a display Part 9631b, display mode switching switch 9034, power switch 9035, power saving mode It has a code change switch 9036, a fastener 9033, and an operating switch 9038.

[0325] The semiconductor device shown in any of the above embodiments includes a display unit 9631a and a display unit 9631b It can be used for this purpose. Therefore, it is possible to improve the display quality of tablet devices. Cut.

[0326] The display unit 9631a can be partially designated as a touch panel area 9632a, and the display will Data can be entered by touching the operation key 9638. Note that the display unit 96 In 31a, as an example, one half of the area has a display-only function, and the other half of the area The area indicates a configuration having touch panel functionality, but is not limited to this configuration. Display unit 96 The entire area of ​​31a may also be configured to have touch panel functionality. For example, the display unit 9 The entire surface of 631a is used as a touch panel with keyboard buttons, and the display unit 9631b is displayed It can be used as a display screen.

[0327] In addition, in the display unit 9631b, similar to the display unit 9631a, one of the display units 9631b The area can be designated as the touch panel area 9632b. Also, the touch panel keyboard Touch the location where the display toggle button 9639 is displayed using your finger or stylus. This allows keyboard buttons to be displayed on the display unit 9631b.

[0328] Furthermore, simultaneously with respect to the touch panel area 9632a and the touch panel area 9632b You can also use touch input.

[0329] Additionally, the display mode switch 9034 changes the display orientation, such as vertical or horizontal display. You can switch between modes, such as switching between black and white and color displays. Power saving mode switching... The Itch 9036 detects ambient light during use using a light sensor built into the tablet device. The display brightness can be optimized according to the amount of light. The tablet terminal uses optical sensors. In addition to the sensor, other detection devices such as gyroscopes, accelerometers, and other sensors that detect tilt are also used. It can be built-in.

[0330] Furthermore, Figure 24(A) shows an example where the display area of ​​display unit 9631b and display unit 9631a are the same. However, this is not particularly limited, and one size may be different from the other. The quality of the display may also differ. For example, one display panel can provide a higher resolution display than the other. You can also use "ru".

[0331] Figure 24(B) shows the closed state, and the tablet terminal consists of a housing 9630 and a solar cell 9 633, and a charge / discharge control circuit 9634 are included. Note that in Figure 24(B), the charge / discharge control circuit 96 As an example of 34, consider a configuration having a battery 9635 and a DC-DC converter 9636. This is what is being shown.

[0332] Note that the tablet device is foldable, so when not in use, the casing 9630 is closed. This can be done. Therefore, the display units 9631a and 9631b can be protected. We can provide tablet devices that are highly durable and reliable from a long-term use perspective.

[0333] In addition, the tablet devices shown in Figures 24(A) and 24(B) are also available in various forms. Functions to display information (still images, videos, text images, etc.), calendar, date or time, etc. A function that displays information on the display unit, and a touch input operation or editing of the information displayed on the display unit. It has input capabilities, and functions to control processing through various software (programs), etc. It is possible.

[0334] The touch panel is powered by a solar cell 9633 mounted on the surface of the tablet device. It can be supplied to the display unit or the video signal processing unit, etc. The solar cell 9633 is It can be provided on one or both sides of the housing 9630, and efficiently charges the battery 9635. This configuration is preferable because it allows for such a setup. Note that the battery 9635 is lithium Using um-ion batteries offers advantages such as miniaturization.

[0335] Furthermore, the configuration and operation of the charge / discharge control circuit 9634 shown in Figure 24(B) are shown in Figure 24( A block diagram is shown and explained in C). Figure 24(C) shows solar cell 9633, battery 9 635, DC-DC converter 9636, converter 9637, switch SW1 to SW3 The display unit 9631 is shown, along with the battery 9635 and the DC-DC converter 963 6. Converter 9637 and switches SW1 to SW3 control the charge and discharge as shown in Figure 24(B). This corresponds to circuit 9634.

[0336] First, we will explain an example of operation when electricity is generated by the solar cell 9633 using ambient light. The electricity generated by the solar panel is set to a voltage suitable for charging the battery 9635. The CDC converter 9636 performs either a boost or a buck. Then, the display unit 9631 operates as follows: When power from solar cell 9633 is used, switch SW1 is turned ON, and the converter 9637 will boost or lower the voltage to the required level for the display unit 9631. If you do not want to display on 9631, turn SW1 off and turn SW2 on to enable battery The configuration should be designed to charge the 9635.

[0337] While the solar cell 9633 is shown as an example of a power generation method, it is not particularly limited to this method. , by other power generation methods such as piezoelectric elements (piezo elements) and thermoelectric elements (Peltier elements) The configuration may also include charging the battery 9635. For example, power may be supplied wirelessly (contactlessly). This can be done using a contactless power transmission module that transmits and receives power for charging, or by combining it with other charging methods. It can also be used as a composition.

[0338] The configurations shown in this embodiment may be combined with the configurations shown in other embodiments as appropriate. It can be used.

Claims

1. A first conductive layer and a second conductive layer, A first insulating layer having a region above the first conductive layer and a region above the second conductive layer, A first metal oxide layer having a region above the first insulating layer, A second metal oxide layer having a region above the first insulating layer, A third conductive layer, A fourth conductive layer, A fifth conductive layer, A second insulating layer having a region above the third conductive layer, a region above the fourth conductive layer, and a region above the fifth conductive layer, It has a sixth conductive layer that is translucent, The first conductive layer has a region that functions as the gate electrode of a transistor in the pixel, The second conductive layer has the function of supplying potential to the second metal oxide layer. The first insulating layer has a region that functions as a gate insulating layer for the transistor, The first metal oxide layer has a region that functions as a channel formation region of the transistor, The second metal oxide layer is translucent, The third conductive layer has the function of supplying a potential corresponding to the video signal to either the source or the drain of the transistor. The fourth conductive layer has the function of electrically connecting the source or drain of the transistor to the sixth conductive layer. The fifth conductive layer has the function of electrically connecting the second conductive layer and the second metal oxide layer. The second insulating layer is translucent, The sixth conductive layer has a region that functions as a pixel electrode of the liquid crystal element, A portion of the sixth conductive layer, a portion of the second insulating layer, and a portion of the second metal oxide layer form a capacitance. In a plan view of the pixel, the first conductive layer is arranged extending in a first direction. In a plan view of the pixel, the second conductive layer is arranged extending in the first direction. In a plan view of the pixel, the first conductive layer has a first region including a region protruding in a second direction intersecting the first direction, and a second region having a narrower width in the second direction than the first region. In a plan view of the pixel, the entirety of the first metal oxide layer is arranged to overlap with the first region. In a plan view of the pixel, the region where the fourth conductive layer and the sixth conductive layer are in contact is located in the region sandwiched between the second region and the second conductive layer. In a plan view of the pixel, the region where the sixth conductive layer and the second metal oxide layer overlap has a width in the second direction greater than the width in the first direction. In a plan view of the pixel, the distance between the first conductive layer and the second conductive layer in the second direction is smaller than the width of the region where the sixth conductive layer and the second metal oxide layer overlap in the second direction. The fifth conductive layer is electrically connected to the second conductive layer via a first contact hole provided in the first insulating layer. The sixth conductive layer is electrically connected to the fourth conductive layer via a second contact hole provided in the second insulating layer. A liquid crystal display device wherein the light-shielding layer having a region above the liquid crystal layer of the liquid crystal element overlaps with the first metal oxide layer, overlaps with the first contact hole, overlaps with the second contact hole, and overlaps with the region where the fifth conductive layer and the second metal oxide layer overlap.

2. In claim 1, A liquid crystal display device wherein the first metal oxide layer and the second metal oxide layer contain indium.

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