Semiconductor Devices

Abstract

To achieve high reliability by giving stabilized electrical characteristics to a semiconductor device using an oxide semiconductor.SOLUTION: A semiconductor device has an insulating film, a first metal oxide film on the insulating film in contact therewith, an oxide semiconductor film partially in contact with the first metal oxide film, a source electrode and a drain electrode for connection electrically with the oxide semiconductor film, a second metal oxide film partially in contact with the oxide semiconductor film, a gate insulator film on the second metal oxide film in contact therewith, and a gate electrode on the gate insulator film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor device and a method for manufacturing the semiconductor device.

[0002] In this specification, a semiconductor device is a device that can function by utilizing semiconductor characteristics. The term "semiconductor device" refers to devices in general, and electro-optical devices, semiconductor circuits, and electronic equipment are all semiconductor devices. [Background technology]

[0003] A technology for constructing transistors using semiconductor thin films formed on substrates with insulating surfaces These transistors are used in integrated circuits (ICs) and image display devices (display devices). It is widely used in such electronic devices. Silicon-based semiconductor materials are widely known, but oxide semiconductors are also attracting attention. are.

[0004] For example, the active layer of a transistor is 18 / cm 3 Less than The amorphous oxide containing indium (In), gallium (Ga), and zinc (Zn) is used. A transistor using this method has been disclosed (see Patent Document 1).

[0005] Transistors using oxide semiconductors have higher performance than transistors using amorphous silicon. They have a faster operating speed and are easier to manufacture than transistors using polycrystalline silicon. However, it is known that the electrical characteristics of these devices are easily fluctuated and their reliability is low. The threshold voltage of the transistor varies before and after the BT test. Patent Documents 2 and 3 disclose a method for determining the threshold voltage of a transistor using an oxide semiconductor. In order to suppress the shift, a layer is provided on at least one of the upper surface and the lower surface of the oxide semiconductor layer. A technology has been developed to prevent charge trapping at the interface of an oxide semiconductor layer by using an interface stabilization layer. is shown. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-165528 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-16347 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-16348 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the transistors disclosed in Patent Document 2 and Patent Document 3 are not interface stabilized. The layer used is a layer having the same properties as the gate insulating layer and the protective layer, and the interface with the active layer Therefore, the charge transport at the interface between the active layer and the interface stabilization layer cannot be maintained in a good condition. In particular, it is difficult to suppress the bandgap between the interface stabilization layer and the active layer. If the capacitor has a large capacitance, charge accumulation can easily occur.

[0008] Therefore, it is believed that transistors including oxide semiconductors still have sufficient reliability. I can't say.

[0009] In view of such problems, a method for providing stable electrical characteristics to a semiconductor device using an oxide semiconductor has been proposed. One of the objectives is to achieve high reliability. [Means for solving the problem]

[0010] One embodiment of the disclosed invention is a semiconductor device including an insulating film such as a gate insulating film or a protective insulating film and an active layer. The oxide semiconductor films are not in direct contact with each other, but are in contact with metal oxide films. The present invention relates to a method for manufacturing a semiconductor device, and a method for manufacturing a semiconductor device, the method comprising the steps of: That is, one embodiment of the disclosed invention is a metal oxide film and an oxide semiconductor. An insulating film made of a different component from the conductor film, a metal oxide film, and an oxide semiconductor film are stacked. Here, the term "component of the same kind as the oxide semiconductor film" means a component of the oxide semiconductor film. It means that one or more metal elements selected from the constituent elements are contained.

[0011] By providing such a laminated structure, it is possible to reduce the electric current that may be generated due to the operation of the semiconductor device. The trapping of charges and the like at the interface between the insulating film and the oxide semiconductor film can be sufficiently suppressed. This effect can be achieved by using a material that is compatible with the oxide semiconductor film. By providing a metal oxide film in contact with an oxide semiconductor film, the operation of a semiconductor device can be improved. Charges generated due to the above phenomenon are trapped at the interface between the oxide semiconductor film and the metal oxide film. and an insulating film made of a material that can form a charge trapping center at the interface. is present in contact with the metal oxide film, This is due to the mechanism that allows the above-mentioned charges to be trapped.

[0012] That is, when a large amount of charge is generated in a metal oxide film alone, the oxide semiconductor film It becomes difficult to suppress the trapping of charges at the interface of the metal oxide film. By providing the insulating film, charges are preferentially captured at the interface between the metal oxide film and the insulating film, This makes it possible to suppress trapping of charges at the interface between the oxide semiconductor film and the metal oxide film. As described above, the effect of one embodiment of the disclosed invention is that the insulating film, the metal oxide film, and the acid The metal oxide film and the oxide semiconductor film are laminated. It can be said that the effect produced by the laminated structure of the conductive film is different in nature.

[0013] Then, the trapping of charges at the interface of the oxide semiconductor film is suppressed, and the trapping center of the charges is located in the oxide The above-mentioned effect of being able to keep the semiconductor film away from the semiconductor device prevents malfunctions of the semiconductor device. This can suppress the occurrence of defects and improve the reliability of the semiconductor device.

[0014] In addition, from the above-mentioned mechanism, it is desirable that the metal oxide film has a sufficient thickness. When the metal oxide film is thin, the influence of charges trapped at the interface between the metal oxide film and the insulating film For example, a metal oxide film may have a larger thickness than an oxide semiconductor film. It is preferable to make it shorter.

[0015] The insulating metal oxide film is formed between the source electrode and the drain electrode and the oxide semiconductor. Since the oxide film is formed in a manner that does not interfere with the connection with the source electrode or drain electrode, An increase in resistance can be prevented compared to when a metal oxide film exists between the semiconductor film and the metal oxide film. Therefore, deterioration in the electrical characteristics of the transistor can be suppressed.

[0016] In the thin film formation process, oxide semiconductors may have a stoichiometric composition due to an excess or deficiency of oxygen. If there is a deviation from the normal state or if hydrogen or moisture that forms electron donors gets mixed in, the electrical conductivity This phenomenon is a major problem for transistors using oxide semiconductors. Therefore, hydrogen, moisture, hydroxyl groups, or hydrides (hydrogen compounds) impurities such as SiO 2 and SiO 2 are intentionally removed from the oxide semiconductor, and the oxide semiconductor is At the same time, oxygen, the main component material that makes up oxide semiconductors, is reduced. This makes the oxide semiconductor film highly purified and electrically i-type (intrinsic).

[0017] An i-type (intrinsic) oxide semiconductor is an oxide semiconductor that has n-type impurities, i.e., hydrogen, removed from it. By purifying the oxide semiconductor to the extent possible, it is possible to minimize the amount of impurities other than the main component. (intrinsic) oxide semiconductor or oxide semiconductor that is as close to i-type (intrinsic) as possible. be.

[0018] In the step of making the oxide semiconductor film i-type, It is also possible to simultaneously convert a metal oxide film into an i-type film. The metal oxide films provided on the upper and lower surfaces of the compound semiconductor film are resistant to impurities such as moisture and hydrogen. It is desirable that the metal oxide film is one in which the conductivity is sufficiently reduced and electrically i-type.

[0019] A transistor including a highly purified oxide semiconductor film has a low threshold voltage, an on-state current, and the like. The electrical characteristics of the transistor are almost temperature-dependent. There is also little fluctuation.

[0020] One embodiment of the disclosed invention is a semiconductor device including an insulating film and a first metal oxide film on the insulating film and in contact with the insulating film. a metal oxide film, an oxide semiconductor film that is in contact with a part of the first metal oxide film, and an oxide semiconductor film electrically connected to the oxide semiconductor film. a source electrode and a drain electrode which are electrically connected to the oxide semiconductor film, and a second gold electrode which is partially in contact with the oxide semiconductor film; a gate insulating film on the second metal oxide film and in contact with the second metal oxide film; and a gate electrode on the gate insulating film.

[0021] In the above, the first metal oxide film and the second metal oxide film have a structure of an oxide semiconductor film. The first metal oxide film and the second metal oxide film may contain a compound element. The energy gap of the oxide semiconductor film may be larger than that of the oxide semiconductor film. The energy of the bottom of the conduction band of the first metal oxide film and the second metal oxide film is , which may be higher than the minimum energy of the conduction band of the oxide semiconductor film.

[0022] In the above, the first metal oxide film and the second metal oxide film are made of gallium oxide. The ratio of the constituent elements of the first metal oxide film to the ratio of the constituent elements of the second metal oxide film may be The ratio of the constituent elements of the metal oxide film may be equal. The gate insulating film may be made of silicon oxide or hafnium oxide. It may consist of

[0023] In the above, the second metal oxide film covers the source electrode and the drain electrode, The oxide semiconductor film may be provided in contact with the first metal oxide film. The first metal oxide film may be surrounded by a first metal oxide film and a second metal oxide film.

[0024] In the above, the side edge of the oxide semiconductor film in the channel length direction and the first metal oxide film In addition, the side edges of the oxide semiconductor film in the channel length direction may coincide with each other. The side edge of the first metal oxide film in the channel length direction may coincide with the side edge of the second metal oxide film in the channel length direction.

[0025] In the above, a second insulating film covering the gate insulating film and the gate electrode is provided. In some cases, a conductive film is provided under the oxide semiconductor film.

[0026] In the above, the transistor width determined by the distance between the source electrode and the drain electrode is The channel length L of the capacitor is 10 nm or more and 10 μm or less, for example, 0.1 μm to 0.5 μm. Of course, the channel length L may be 1 μm or more. The channel width W can also be set to 10 nm or more. [Effects of the Invention]

[0027] According to one embodiment of the present invention, a transistor having stable electrical characteristics is provided.

[0028] According to one embodiment of the present invention, a transistor having favorable electrical characteristics and high reliability is provided. A semiconductor device is provided. [Brief explanation of the drawings]

[0029] [Figure 1] 1A and 1B are a plan view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 2] FIG. 10 is a band diagram of a transistor including an oxide semiconductor film and a metal oxide film. [Figure 3] 1A to 1C illustrate one embodiment of a semiconductor device. [Figure 4] 1A to 1C illustrate an example of a manufacturing process of a semiconductor device. [Figure 5] 1A to 1C illustrate an example of a manufacturing process of a semiconductor device. [Figure 6] 1A to 1C illustrate one embodiment of a semiconductor device. [Figure 7] 1A to 1C illustrate one embodiment of a semiconductor device. [Figure 8] 1A to 1C illustrate one embodiment of a semiconductor device. [Figure 9]1A to 1C illustrate one embodiment of a semiconductor device. [Figure 10] 1A and 1B are diagrams illustrating electronic devices. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following description, and it is understood by those skilled in the art that various modifications may be made to the modes and details thereof. The present invention will be easily understood by reading the following description of the embodiments. It is not something that is done.

[0031] The ordinal numbers such as 1st and 2nd are used for convenience and do not represent the order of processes or stacking. In addition, the present specification does not indicate the order in which the invention is specified. It does not indicate the name.

[0032] (Embodiment 1) In this embodiment mode, one mode of a semiconductor device and a manufacturing method of the semiconductor device will be described with reference to FIGS. This will be explained using:

[0033] <Configuration Example of Semiconductor Device> FIG. 1 illustrates a transistor 110 as an example of a semiconductor device according to one embodiment of the disclosed invention. 1A is a plan view, and FIG. 1B and FIG. 1C are cross-sectional views. (C) is a cross-sectional view of the AB section and the CD section in FIG. 1(A), respectively. Note that in FIG. 1A, components of the transistor 110 are not shown in order to avoid complication. 2. A part of the metal oxide film 210 is omitted.

[0034] The transistor 110 shown in FIG. 1 includes an insulating film 202, a first metal oxide film, and a film 204, an oxide semiconductor film 206, a source electrode 208a, a drain electrode 208b, a second It includes a metal oxide film 210 , a gate insulating film 212 , and a gate electrode 214 .

[0035] In the transistor shown in FIG. 1, the second metal oxide film 210 is and the drain electrode 208b, and is in contact with a part of the first metal oxide film 204. In addition, in FIG. 1, the first metal oxide film 204 and the second metal oxide film The oxide semiconductor film 206 is in contact with the oxide semiconductor film 210 in a region where the oxide semiconductor film 206 is not present. The oxide semiconductor film 206 is formed on the first metal oxide film 204 and the second metal oxide film 210. Surrounded.

[0036] Here, the first metal oxide film 204 and the second metal oxide film 210 are made of an oxide semiconductor film. It is preferable to use an oxide having the same composition as that of the oxide semiconductor film 206. The film is made of an oxide of one or more metal elements selected from the constituent elements. The material is compatible with the oxide semiconductor film 206, and is used as the first metal oxide film 204 and the second metal oxide film 206. By using the metal oxide film 210, the state of the interface with the oxide semiconductor film can be kept good. In other words, the above-mentioned materials can be used for the first metal oxide film 204 and the second metal oxide film 205. By using the oxide semiconductor film 210, the interface between the oxide semiconductor film and the metal oxide film in contact therewith (here, The interface between the first metal oxide film 204 and the oxide semiconductor film 206 or the second metal oxide film Therefore, trapping of charges at the interface between the oxide semiconductor film 210 and the oxide semiconductor film 206 can be suppressed. is.

[0037] The first metal oxide film 204 and the second metal oxide film 210 are both oxide semiconductors. Since the oxide semiconductor film 206 is made of the same material as the oxide semiconductor film 206, the oxide semiconductor film 206 is In the case where the first metal oxide film 204 and the second metal oxide film 210 are in contact with each other, In addition, the adhesion of the constituent elements of the first metal oxide film 204 can be improved. It is more desirable to make the ratio equal to the ratio of the constituent elements of the second metal oxide film 210.

[0038] Since the oxide semiconductor film 206 is used as an active layer, the first metal oxide film 204 The energy gap of the second metal oxide film 210 is The gap between the first metal oxide film 204 and the oxide semiconductor Between the second metal oxide film 210 and the oxide semiconductor film 206, or between the second metal oxide film 210 and the oxide semiconductor film 206, At the very least, carriers should not flow out of the oxide semiconductor film 206 at room temperature (20° C.). For example, the first metal oxide film 204 and the second metal The energy difference between the bottom of the conduction band of the oxide film 210 and the bottom of the conduction band of the oxide semiconductor film 206 is or the top of the valence band of the first metal oxide film 204 or the second metal oxide film 210 and the upper end of the valence band of the oxide semiconductor film 206 is 0.5 eV or more. It is desirable that the value is 0.7 eV or more, and more desirable that the value is 1.5 eV or less. It's nice.

[0039] Specifically, for example, an In—Ga—Zn—O-based material is used for the oxide semiconductor film 206. In this case, the first metal oxide film 204 and the second metal oxide film 205 are formed using a material containing gallium oxide. The oxide film 210 can be formed by gallium oxide and In-Ga-Zn-O based materials. When the two are in contact, the energy barrier is approximately 0.8 eV on the conduction band side and approximately 1.5 eV on the valence band side. It becomes 0.9 eV.

[0040] Gallium oxide is GaO x It is also expressed as a stoichiometric excess of oxygen. For example, it is preferable to set the value of x to 1.4 or more and 2.0 or less. It is preferable that the value of x is 1.5 or more and 1.8 or less. However, gallium oxide The film contains group 3 elements such as yttrium, group 4 elements such as hafnium, and aluminum. Contains impurity elements other than hydrogen, such as group 13 elements, group 14 elements such as silicon, and nitrogen. By doing so, the energy gap of gallium oxide may be widened to improve the insulating properties. The energy gap of a gallium oxide film that does not contain impurities is 4.9 eV. For example, by including more than 0 atomic % and up to 20 atomic % of the element, the energy gap The band gap can be expanded to about 6 eV.

[0041] From the viewpoint of reducing the charge generation source and trapping centers, the water in the metal oxide film It is desirable that impurities such as silicon and water are sufficiently reduced. This is the same idea as reducing impurities in conductive films.

[0042] The insulating film 202 and the gate insulating film 212 are covered with the first metal oxide film 204 and the second metal oxide film 205. By contacting the metal oxide film 210, charge trapping centers may be formed at the interface. It is desirable to use such a material for the insulating film 202 and the gate insulating film 212. As a result, the charges are transferred to the interface between the insulating film 202 and the first metal oxide film 204 or to the gate insulating film 206. The first metal oxide film 212 is trapped at the interface between the first metal oxide film 210 and the second metal oxide film 210. Charge trapping at the interface between the second metal oxide film 204 and the oxide semiconductor film 206, or Therefore, charge trapping at the interface of the oxide semiconductor film 206 can be sufficiently suppressed. However, there are many charge trapping centers at the interface between the gate insulating film 212 and the second metal oxide film 210. If multiple transistors are formed, the transistor characteristics may be deteriorated. The charge trapping is small compared to the interface between the oxide semiconductor film 206 and the second metal oxide film 210. It is preferable that the center is easily formed.

[0043] Specifically, the insulating film 202 and the gate insulating film 212 are made of silicon oxide, silicon nitride, Aluminum oxide, aluminum nitride, a mixture of these, etc. may be used. The first metal oxide film 204 and the second metal oxide film 210 are made of a material containing gallium oxide. In this case, the insulating film 202 and the gate insulating film 212 are made of silicon oxide, silicon nitride, or the like. It is preferable to use the first metal oxide film 204 and the second metal oxide film 21. 0, the energy gap of the insulating film 202 and the gate insulating film 212 is The energy gap of the metal oxide film 204 and the second metal oxide film 210 is larger than that of the metal oxide film 204 and the second metal oxide film 210. desirable.

[0044] The interface between the insulating film 202 and the first metal oxide film 204 or the gate insulating film 21 Therefore, a charge trapping center can be formed at the interface between the first metal oxide film 210 and the second metal oxide film 210. Therefore, the materials of the insulating film 202 and the gate insulating film 212 do not need to be limited to those mentioned above. In addition, the interface between the insulating film 202 and the first metal oxide film 204 or the interface between the gate insulating film 212 and the A treatment may be performed to form a charge trapping center at the interface with the second metal oxide film 210. Such treatments include, for example, plasma treatment and element addition treatment (ion implantation, etc.). There is.

[0045] A second insulating film may be further provided on the transistor 110. In order to electrically connect the source electrode 208a and the drain electrode 208b to the wiring, an insulating film 2 02, the first metal oxide film 204, the second metal oxide film 210, the gate insulating film 212, etc. An opening may be formed in the oxide semiconductor film 206. The oxide semiconductor film 206 may have a second gate electrode. It is preferable that the particles are formed in an island shape, but they do not have to be formed in an island shape.

[0046] FIG. 2 shows the above-mentioned transistor 110, that is, the insulating film, the metal oxide, and the like, from the gate electrode GE side. Energy in a structure in which a carbide film, an oxide semiconductor film, a metal oxide film and an insulating film are joined -band diagram (schematic diagram), E F is the Fermi level of the oxide semiconductor film. Assuming an ideal situation where the insulating film, metal oxide film, and oxide semiconductor film are all intrinsic, The insulating film is made of silicon oxide (SiO x ) (Band gap Eg8eV~9eV) , gallium oxide (GaO) as a metal oxide film x ) (Band gap Eg 4.9 eV) As an oxide semiconductor film (OS), an In-Ga-Zn-O based non-single crystal film (band gap Eg 3.15 eV). The energy difference between the vacuum level and the conduction band edge of gallium oxide is 0.95 eV. The energy difference between the vacuum level and the conduction band of the In-Ga-Zn-O non-single crystal film is 3.5 eV. The energy difference at the lower end is 4.3 eV.

[0047] As shown in FIG. 2, the gate electrode side (channel side) of the oxide semiconductor film is made of an oxide semiconductor and There are energy barriers of about 0.8 eV and about 0.95 eV at the interfaces with the metal oxide. Similarly, the oxide semiconductor film is also formed on the back channel side (opposite to the gate electrode) of the oxide semiconductor film. There are energy barriers of approximately 0.8 eV and 0.95 eV at the interface between the metal and the metal oxide. Such an energy barrier exists at the interface between an oxide semiconductor and a metal oxide. This prevents the carriers from moving at the interface, so the carriers They move through the oxide semiconductor without moving from the body to the metal oxide. As shown in Figure 2, The oxide semiconductor film, the metal oxide layer, and the insulating layer are formed such that the oxide semiconductor film is thicker than the oxide semiconductor. Materials with gradually increasing band gaps (insulating film band gaps are larger than metal oxide films) Such beneficial results can be achieved by placing the conductor between two electrodes (the conductor is larger).

[0048] 3A to 3G show cross-sectional views of transistors having different structures from the transistor 110. 3A to 3G show a surface structure of a transistor according to one embodiment of the disclosed invention. A top-gate transistor is shown as an example.

[0049] The transistor 120 shown in FIG. 3A includes an insulating film 202, a first metal oxide film 204, The oxide semiconductor film 206, the source electrode 208a, the drain electrode 208b, the second metal oxide 210, a gate insulating film 212, and a gate electrode 214. The transistor 120 is different from the transistor 110 in that the oxide semiconductor film 20 6 is the position where the source electrode 208a and the drain electrode 208b are connected. In the transistor 120, the source electrode 208a and the drain electrode 208b are formed under the oxide semiconductor film 206. The other components are the same as those of the transistor 11 in FIG. 0. For details, please refer to the description of Figure 1.

[0050] The transistor 130 shown in FIG. 3B is similar to the transistor 130 shown in FIG. 3A in that it includes the above-described components. The transistor 130 is common to the transistor 120 shown in FIG. The difference is that the insulating film 202 has a convex shape, and the oxide semiconductor film 206 is a first metal oxide. The metal oxide film 204 and the second metal oxide film 210 are not completely covered. The other components are the same as those in Figure 3(A).

[0051] The transistor 140 shown in FIG. 3C is similar to the transistor 140 shown in FIG. 3B in that it includes the above-described components. The transistor 140 and the transistor 130 are common. The difference is that the insulating film 202 has a flat shape, and the first metal oxide film 204 has a convex shape. In addition, when the substrate 200 has the function of the insulating film 202, the insulating film 202 is set. The other components are the same as those in FIG. 3(B).

[0052] The transistors 150, 160, and 1 and 2, respectively, in that they include the above-mentioned components. The transistor 110, the transistor 120, and the transistor The difference between them is the first metal oxide film. The difference is whether the second metal oxide film 204 or the second metal oxide film 210 is processed into an island shape. The components are the same as those in FIG. 1 and FIG. 3(A) to FIG. 3(C).

[0053] <Example of transistor manufacturing process> 4 and 5, a manufacturing process of the transistor shown in FIG. 1 or FIG. 3A will be described below. An example of this will be described.

[0054] <Fabrication process of transistor 110> 4A to 4E, an example of a manufacturing process of the transistor 110 shown in FIG. 1 will be described. Note that the manufacturing process of the transistor 150 shown in FIG. The first metal oxide film 204 and the like are processed to match the shape of the conductive film 206. The manufacturing process is the same as that of the transistor 110.

[0055] First, an insulating film 202 is formed on a substrate 200, and a first A metal oxide film 204 is formed (see FIG. 4(A)).

[0056] There is no particular restriction on the material of the substrate 200, but it should be at least strong enough to withstand the subsequent heat treatment. It is necessary to have heat resistance. For example, glass substrate, ceramic substrate, quartz substrate A sapphire substrate or the like can be used as the substrate 200. In addition, silicon or carbide Single crystal semiconductor substrates such as silicon, polycrystalline semiconductor substrates, compounds such as silicon germanium It is also possible to apply a semiconductor substrate, an SOI substrate, etc., and to form a semiconductor element on these substrates. The substrate 200 may be one on which a substrate is provided.

[0057] A flexible substrate may be used as the substrate 200. When providing the transistor, the transistor may be directly formed on the flexible substrate, or the transistor may be formed on another substrate. After the transistor is formed, it may be peeled off and transferred to a flexible substrate. In order to peel off the transistor and transfer it to a flexible substrate, a peeling It is advisable to form a separation layer.

[0058] The insulating film 202 is in contact with the first metal oxide film 204, and the insulating film 202 is formed at the interface. It is desirable to use a material in which a charge trapping center can be formed. By using the insulating film 202 as the first metal oxide film 204, the charges are trapped at the interface between the insulating film 202 and the first metal oxide film 204. Therefore, charge trapping at the interface between the first metal oxide film 204 and the oxide semiconductor film 206 is sufficiently achieved. It will be possible to suppress it.

[0059] Specifically, the insulating film 202 may be made of silicon oxide, silicon nitride, aluminum oxide, or nitride. For example, the first metal oxide film may be made of aluminum oxide, a mixture of these materials, or the like. When the insulating film 204 is made of a material containing gallium oxide, the insulating film 202 is made of silicon oxide or It is preferable to use silicon nitride or the like. In this regard, the energy gap of the insulating film 202 is larger than the energy gap of the first metal oxide film 204. It is desirable that it is larger than the cap.

[0060] In addition, a charge trapping center is formed at the interface between the insulating film 202 and the first metal oxide film 204. If it is possible to do so, the material of the insulating film 202 does not need to be limited to those mentioned above. The process is such that a charge trapping center is formed at the interface between the insulating film 202 and the first metal oxide film 204. Such treatments include, for example, plasma treatment and element addition treatment ( ion implantation, etc.

[0061] The method for producing the insulating film 202 is not particularly limited, but may be, for example, a plasma CVD method or a sputtering method. The insulating film 202 can be formed by a film formation method such as a coating method. The insulating film 2 may have a single layer structure or a multilayer structure containing the above-mentioned materials.

[0062] When the substrate 200 contains the insulating material as described above, the substrate 200 can be treated as the insulating film 202. In other words, the insulating film 202 referred to here In this case, the substrate 200 is made of silicon oxide or the like. It is more desirable that:

[0063] The first metal oxide film 204 is made of an oxide having the same components as the oxide semiconductor film 206. Such a material is compatible with the oxide semiconductor film 206, and By using the metal oxide film 204, the state of the interface with the oxide semiconductor film can be kept good. In other words, by using the above-mentioned materials for the first metal oxide film 204, The interface between the oxide semiconductor film and the metal oxide film in contact therewith (here, the first metal oxide film 204 Therefore, it is possible to suppress trapping of charges at the interface between the oxide semiconductor film 206 and the silicon dioxide film 208. .

[0064] Since the oxide semiconductor film 206 is used as an active layer, the first metal oxide film 204 The energy gap of the oxide semiconductor film 206 is larger than that of the oxide semiconductor film 206. In addition, at least a thickness of 100 nm is required between the first metal oxide film 204 and the oxide semiconductor film 206. At room temperature (20° C.), the energy is low enough that carriers do not flow out of the oxide semiconductor film 206. For example, the lower end of the conduction band of the first metal oxide film 204 and The energy difference between the lower end of the conduction band of the oxide semiconductor film 206 and the lower end of the conduction band of the first metal oxide film The energy difference between the top of the valence band of the oxide semiconductor film 204 and the top of the valence band of the oxide semiconductor film 206 is It is desirable that the value is 0.5 eV or more, and more desirable that the value is 0.7 eV or more. It is desirable that the electron density is 5 eV or less.

[0065] From the viewpoint of reducing the charge generation source and trapping centers, the water in the metal oxide film It is desirable that impurities such as silicon and water are sufficiently reduced. This is the same idea as reducing impurities in conductive films.

[0066] There is no particular limitation on the method for producing the first metal oxide film 204. For example, a plasma CVD method or The first metal oxide film 204 can be formed by a film forming method such as sputtering. In addition, sputtering methods are suitable in that they are less likely to be contaminated with hydrogen or water. On the other hand, in terms of improving the quality of the film, plasma CVD methods are suitable.

[0067] Next, an oxide semiconductor film is formed over the first metal oxide film 204. The oxide semiconductor film is processed to form an island-shaped oxide semiconductor film 206 (see FIG. 4B).

[0068] The oxide semiconductor film is preferably formed by a method that does not easily allow hydrogen, water, or the like to be mixed in. The oxide semiconductor film can be formed by a method such as sputtering. The thickness of the oxide semiconductor film is preferably 3 nm to 30 nm. For example, if the film thickness is 50 nm or more, the transistor may become normally on. The insulating film 202, the first metal oxide film 204, and the oxide semiconductor film are It is preferable to form the films continuously without exposing them to the air.

[0069] The material used for the oxide semiconductor film is the quaternary metal oxide In-Sn-Ga-Z nO system, and ternary metal oxides such as In-Ga-Zn-O system and In-Sn-Zn-O system , In-Al-Zn-O system, Sn-Ga-Zn-O system, Al-Ga-Zn-O system, Sn- Al-Zn-O system, binary metal oxides such as In-Zn-O system, Sn-Zn-O system, A l-Zn-O series, Zn-Mg-O series, Sn-Mg-O series, In-Mg-O series, In-Ga -O system, and single element metal oxides such as In-O system, Sn-O system, and Zn-O system can be used. In addition, SiO2 may be included in the above materials. The a-Zn-O material is a material containing indium (In), gallium (Ga), and zinc (Zn). The composition ratio is not particularly important. It may contain elements other than those mentioned above.

[0070] The oxide semiconductor film has the chemical formula InMO3(ZnO) m Materials expressed as (m>0) Here, M is selected from Ga, Al, Mn and Co. For example, M may be Ga, Ga and Al, Ga and and Mn, or Ga and Co, etc. can be used.

[0071] In this embodiment, the oxide semiconductor film is formed using a substrate for forming an In—Ga—Zn—O-based oxide semiconductor film. The film is formed by sputtering using a target.

[0072] When using an In-Ga-Zn-O-based material as the oxide semiconductor, the target to be used is For example, the composition ratio is In2O3:Ga2O3:ZnO=1:1:1 [mol A target for forming an oxide semiconductor film having a ratio of [0.01 to 0.01] can be used. The composition and the thickness are not necessarily limited to those described above. For example, In2O3:Ga2O3:ZnO=1: A target for forming an oxide semiconductor film having a composition ratio of 1:2 (molar ratio) can also be used.

[0073] In addition, when an In-Zn-O-based material is used as the oxide semiconductor, the target to be used The composition ratio is In:Zn=50:1 to 1:2 in atomic ratio (converted to In2O3 In:ZnO=25:1 to 1:4), preferably In:Zn=20:1 to 1:1 (in terms of molar ratio) In2O3:ZnO=10:1 to 1:2), more preferably In:Zn=15 :1 to 1.5:1 (converted to a molar ratio of In2O3:ZnO = 15:2 to 3:4) For example, the target used to form an In-Zn-O-based oxide semiconductor has an atomic ratio of In When Zn:O=X:Y:Z, Z>1.5X+Y.

[0074] The filling rate of the oxide target should be between 90% and 100%, preferably between 95% and 99%. 9% or less. By using a target for oxide semiconductor film formation with a high filling factor, film formation This is because the oxide semiconductor film can be a dense film.

[0075] The film formation atmosphere is a rare gas (typically argon) atmosphere, an oxygen atmosphere, or a rare The oxide semiconductor film may be heated under a mixed atmosphere of hydrogen, water, hydroxyl, or the like. To prevent contamination with impurities such as hydrogen, water, hydroxyl groups, and hydrides, It is desirable to use an atmosphere using a highly purified gas that has been thoroughly removed.

[0076] For example, the oxide semiconductor film can be formed as follows.

[0077] First, the substrate 200 is held in a film-forming chamber maintained in a reduced pressure state, and the substrate temperature is increased to 100° C. or higher. The temperature is set to 600°C or less, preferably 200°C or more and 400°C or less. By forming the oxide semiconductor film in this manner, the impurity concentration in the oxide semiconductor film can be reduced. In addition, damage to the oxide semiconductor film due to sputtering can be reduced. is.

[0078] Next, the remaining moisture in the film-forming chamber is removed, and impurities such as hydrogen and moisture are thoroughly removed. A high-purity gas containing the target was introduced, and an oxide semiconductor film was formed on the substrate 200 using the target. To remove the residual moisture in the deposition chamber, a cryopump or an ion pump is used as an exhaust means. It is desirable to use an adsorption type vacuum pump such as a ion pump or titanium sublimation pump. The exhaust means may be a turbo pump with a cold trap added. The deposition chamber evacuated using a cryopump contains gases such as hydrogen molecules and water (H2O). Compounds containing hydrogen atoms (and more preferably compounds containing carbon atoms) have been removed. Therefore, the concentration of impurities contained in the oxide semiconductor film formed in the deposition chamber can be reduced.

[0079] As an example of film formation conditions, the distance between the substrate and the target is 100 mm, and the pressure is 0.6 P. a, DC power supply: 0.5 kW, film deposition atmosphere: oxygen (oxygen flow rate: 100%) In addition, when a pulsed DC power supply is used, the powdery material (pulse) generated during film formation can be easily removed. This is preferable because it reduces the amount of dust (also called "articles" or "dust") and reduces the variation in film thickness.

[0080] Note that before the oxide semiconductor film is formed by a sputtering method, argon gas is introduced. The reverse sputtering is performed to generate plasma, and the metal oxide adheres to the surface of the first metal oxide film 204. It is preferable to remove the powdery material (also called particles or dust) that is present in the sputtering. is a method in which a voltage is applied to a substrate, plasma is generated near the substrate, and the surface of the substrate is modified. It should be noted that instead of argon, gas such as nitrogen, helium, or oxygen may be used.

[0081] The oxide semiconductor film is processed by forming a mask of a desired shape on the oxide semiconductor film. The above mask can be used for etching the oxide semiconductor film. It can be formed by using a method such as lithography. Any method may be used to form the mask. By processing the metal oxide film 204 and the like, the transistor shown in FIG. 150 can be made.

[0082] The oxide semiconductor film can be etched by either dry etching or wet etching. Of course, these may be used in combination.

[0083] After that, the oxide semiconductor film is preferably subjected to heat treatment (first heat treatment). The first heat treatment is performed to remove excess hydrogen (including water and a hydroxyl group) in the oxide semiconductor film. The structure of the oxide semiconductor film can be adjusted, and defect levels in the energy gap can be reduced. The temperature of the first heat treatment is 250°C or higher and 650°C or lower, preferably 450°C or higher and 600°C or lower. ° C. or less. The temperature of the first heat treatment is preferably lower than the strain point of the substrate.

[0084] Furthermore, the first heat treatment removes excess hydrogen (water and It is also possible to remove the hydroxyl group.

[0085] The heat treatment is carried out by, for example, placing the object to be treated in an electric furnace using a resistance heating element, etc., and heating the object in a nitrogen atmosphere. The oxide semiconductor film is not exposed to the air during this time. To prevent contamination with water or hydrogen.

[0086] The heat treatment device is not limited to an electric furnace, but may be a device that uses heat conduction or heat radiation from a medium such as a heated gas. For example, a device that heats the object to be treated by irradiation may be used. Rapid Thermal Anneal (GRTA) equipment, Gas Rapid Th RTA (Rapid Thermal Anneal) equipment l) The LRTA device can be used with halogen lamps, metal halide lamps, etc. lamps, xenon arc lamps, carbon arc lamps, high-pressure sodium lamps, high-pressure mercury lamps It is a device that heats the object to be treated by radiating light (electromagnetic waves) emitted from a lamp such as a The GRTA device is a device that performs heat treatment using high-temperature gas. Inert gases that do not react with the material to be treated by heat treatment, such as rare gases such as fluorine or nitrogen. is used.

[0087] For example, in the first heat treatment, the workpiece is placed in a heated inert gas atmosphere and heated for several minutes. After heating for 1 minute, the object to be treated may be taken out of the inert gas atmosphere and subjected to GRTA treatment. GRTA treatment allows high-temperature heat treatment in a short time. It is possible to apply this method even under temperature conditions exceeding the specified temperature. The first heat treatment may be performed in an atmosphere containing oxygen. This is because the defect level in the energy gap caused by oxygen vacancies can be reduced. do.

[0088] The inert gas atmosphere is nitrogen or a rare gas (helium, neon, argon) It is desirable to use an atmosphere containing, as its main component, hydrogen, water, etc. For example, nitrogen or rare gases such as helium, neon, and argon introduced into a heat treatment device are preferable. The purity of 6N (99.9999%) or more, preferably 7N (99.99999%) or more (That is, the impurity concentration is 1 ppm or less, preferably 0.1 ppm or less).

[0089] In either case, the first heat treatment reduces impurities and produces an i-type (intrinsic) semiconductor or i By forming an oxide semiconductor film that is extremely similar to a conventional semiconductor, a transistor with extremely excellent characteristics can be obtained. It is possible to realize the star.

[0090] By the way, the above-mentioned heat treatment (first heat treatment) has the effect of removing hydrogen, water, etc. This heat treatment can also be called a dehydration treatment or a dehydrogenation treatment. The dehydrogenation treatment is performed, for example, after the oxide semiconductor film is processed into an island shape. In addition, such dehydration and dehydrogenation treatments can be carried out not only once. It is okay to do this multiple times.

[0091] Note that in this example, the oxide semiconductor film is processed into an island shape and then the first heat treatment is performed. However, one embodiment of the disclosed invention is not to be construed as being limited thereto. After the above, the oxide semiconductor film may be processed.

[0092] Next, a source electrode and a A conductive film is formed to form the drain electrode (including wiring formed in the same layer). The conductive film is then processed to form a source electrode 208a and a drain electrode 208b. (See FIG. 4C). Note that the edge of the source electrode 208a and the drain electrode The distance between the end of 208b and the channel length L of the transistor is determined. .

[0093] The conductive film used for the source electrode 208a and the drain electrode 208b is, for example, A a metal film containing an element selected from the group consisting of I, Cr, Cu, Ta, Ti, Mo, and W, or the above-mentioned Metal nitride films containing elements (titanium nitride film, molybdenum nitride film, tungsten nitride film) ) or the like can be used. In addition, it is possible to use a metal film such as Al or Cu on either the upper or lower side. Both are made of high melting point metal films such as Ti, Mo, W, etc. or their metal nitride films (titanium nitride film A structure in which a layer of a metal film (a molybdenum nitride film, a tungsten nitride film) is laminated may also be used.

[0094] The conductive film used for the source electrode 208a and the drain electrode 208b is a conductive gold film. It may be formed of a metal oxide. An example of a conductive metal oxide is indium oxide (In2O3). , tin oxide (SnO2), zinc oxide (ZnO), indium oxide tin oxide alloy (In2O 3-SnO2, abbreviated as ITO), indium oxide zinc oxide alloy (In2O3-ZnO ) or a material obtained by adding silicon oxide to these metal oxide materials can be used.

[0095] The conductive film can be processed by etching using a resist mask. The exposure to light when forming the resist mask used for etching is ultraviolet light, KrF laser light, or ArF It is advisable to use a laser beam or the like.

[0096] When performing exposure with a channel length L of less than 25 nm, for example, several nm to several tens of nm Using extreme ultraviolet light with an extremely short wavelength of 1000m, It is recommended to perform exposure when forming a resist mask. Exposure with extreme ultraviolet light has high resolution and focal depth. Therefore, the channel length L of the transistor to be formed later can be reduced. This makes it possible to increase the operating speed of the circuit.

[0097] In addition, etching is performed using a resist mask formed by a so-called multi-tone mask. The resist mask formed using the multi-tone mask has a plurality of film thicknesses. The shape can be further changed by ashing, It can be used in multiple etching processes to process into patterns. A multi-tone mask allows for resist masks that correspond to at least two different patterns. In other words, the process can be simplified.

[0098] Note that when the conductive film is etched, part of the oxide semiconductor film 206 is etched, and a groove is formed. In some cases, the oxide semiconductor film has a recess (depression).

[0099] Then, plasma treatment using gases such as N2O, N2, or Ar is performed to remove the exposed Adsorbed water or the like attached to the surface of the oxide semiconductor film may be removed by performing plasma treatment. In this case, the oxide semiconductor film 206 is not exposed to the air after the plasma treatment. It is desirable to form a second metal oxide film 210 in contact with the portion.

[0100] Next, an oxide semiconductor film is formed on the source electrode 208a and the drain electrode 208b. A second metal oxide film 210 is formed in contact with a part of the second metal oxide film 206. The gate insulating film 212 is formed so as to be in contact with the oxide film 210 (see FIG. 4(D)).

[0101] The second metal oxide film 210 is similar to the first metal oxide film 204 and will not be described in detail. Abbreviated.

[0102] The gate insulating film 212 is similar to the insulating film 202. However, Considering that the material functions as an insulating film, materials with a high relative dielectric constant such as hafnium oxide are used. However, even in this case, the second metal oxide film 210 is in contact with the second metal oxide film 210. Therefore, it is desirable to use a material in which charge trapping centers can be formed at the interface. There is no.

[0103] After the second metal oxide film 210 is formed or after the gate insulating film 212 is formed, The temperature of the second heat treatment is preferably 250°C or higher and 700°C or lower. The temperature of the second heat treatment is preferably 450°C or higher and 600°C or lower. It is preferable to set it to full.

[0104] The second heat treatment is carried out in an atmosphere of nitrogen, oxygen, or ultra-dry air (with a water content of 20 ppm or less, preferably air at 1 ppm or less, preferably 10 ppb or less), or rare gases (argon, helium However, it is preferable to carry out the treatment under an atmosphere of nitrogen, oxygen, ultra-dry air, or a rare gas. It is preferable that the gas does not contain water, hydrogen, etc. Also, the nitrogen, oxygen, etc. introduced into the heat treatment device Or the purity of the rare gas is 6N (99.9999%) or more, preferably 7N (99.999%). 99%) or more (i.e., impurity concentration is 1 ppm or less, preferably 0.1 ppm or less). It is preferable that:

[0105] In the second heat treatment, the oxide semiconductor film 206 and the second metal oxide film 210 are Therefore, the dehydration (or dehydrogenation) treatment reduces Oxygen is one of the main components of oxide semiconductors that may be easily damaged. The second metal oxide film 210 containing the metal oxide can be supplied to the oxide semiconductor film. This makes it possible to reduce charge trapping centers in the oxide semiconductor film.

[0106] Furthermore, this heat treatment can also be used to remove the first metal oxide film 204 or the second metal oxide film 21. Impurities in the 0 are also removed at the same time, resulting in high purity.

[0107] Note that the timing of the second heat treatment is not particularly limited as long as it is performed after the oxide semiconductor film 206 is formed. For example, the second heat treatment may be performed after the gate electrode 214 is formed. The second heat treatment may be performed after the first heat treatment, or the first heat treatment may be performed in combination with the second heat treatment. Alternatively, the second heat treatment may serve as the first heat treatment.

[0108] As described above, by applying at least one of the first heat treatment and the second heat treatment, oxidation The compound semiconductor film 206 is highly purified so that it contains as few impurities as possible other than its main component. In the highly purified oxide semiconductor film 206, carriers derived from donors are extremely The carrier concentration is 1×10 14 / cm 3 Less than 1x1 0 12 / cm 3 less than 1×10 11 / cm 3 is less than.

[0109] Thereafter, the gate electrode 214 is formed (see FIG. 4(E)). Butane, titanium, tantalum, tungsten, aluminum, copper, neodymium, scandium The metal material may be a metal material such as fluorine or an alloy material containing the metal material as a main component. The gate electrode 214 may have a single layer structure or a multilayer structure.

[0110] Through the above steps, the transistor 110 is formed.

[0111] <Fabrication process of transistor 120> 5A to 5E, a manufacturing process of the transistor 120 shown in FIG. 3A will be described. Note that the manufacturing process of the transistor 160 shown in FIG. The second metal oxide film 210 is processed to match the shape of the metal oxide semiconductor film 206. The manufacturing process is the same as that of the transistor 120 .

[0112] First, an insulating film 202 is formed on a substrate 200, and a first A metal oxide film 204 is formed (see FIG. 5A). Please refer to the description of the manufacturing process of 0.

[0113] Next, a source electrode and a drain electrode (the same layer as this) are formed on the first metal oxide film 204. A conductive film for forming a wiring (including wiring formed by the method described above) is formed, and the conductive film is processed to form a A source electrode 208a and a drain electrode 208b are formed (see FIG. 5(B)). For this, the description of the manufacturing process of the transistor 110 can be referred to.

[0114] Next, a source electrode 208a and a drain electrode 208b are formed on the first metal oxide film 204. b) is formed, and the oxide semiconductor film is processed to form an island-shaped oxide semiconductor film. A thin film 206 is formed (see FIG. 5(C)). For details, see the fabrication of the transistor 110. Please refer to the process description.

[0115] Next, an oxide semiconductor film is formed on the source electrode 208a and the drain electrode 208b. A second metal oxide film 210 is formed in contact with a part of the second metal oxide film 206. A gate insulating film 212 is formed so as to be in contact with the oxide film 210 (see FIG. 5(D)). For details, the description of the manufacturing process of the transistor 110 can be referred to.

[0116] Thereafter, the gate electrode 214 is formed (see FIG. 5(E)). Please refer to the description of the manufacturing process of the star 110.

[0117] Through the above steps, the transistor 120 is formed.

[0118] The transistor according to this embodiment has an oxide semiconductor film formed on an upper surface and a lower surface. A metal oxide film made of the same kind of component as the semiconductor film is laminated, and further, the metal oxide film is The surface opposite to the surface in contact with the metal oxide film is provided with a layer different from the metal oxide film and the oxide semiconductor film. In this way, an insulating film made of a material that is compatible with the oxide semiconductor film is provided in contact with the insulating film. The metal oxide film made of the material is in contact with the oxide semiconductor film, Charges that may be generated due to the operation of the semiconductor device or the like are transferred between the oxide semiconductor film and the metal oxide film. The material used is one that can suppress capture at the interface and also allows charge capture centers to form at the interface. By making the insulating material in contact with the metal oxide film, the metal oxide The above-mentioned charges can be trapped at the interface between the film and the insulator. This reduces the effect of charges on the oxide semiconductor film, reducing charge trapping at the oxide semiconductor film interface. It is possible to suppress the fluctuation in the threshold voltage of the transistor caused by the above.

[0119] In addition, the oxide semiconductor film used for the active layer of the transistor is subjected to heat treatment to remove hydrogen, moisture, and Impurities such as hydroxyl groups or hydrides (also called hydrogen compounds) are removed from the oxide semiconductor. The main component material of the oxide semiconductor, which is also reduced during the impurity removal process, By supplying oxygen as a material, the oxide semiconductor film is highly purified and electrically becomes i-type ( The transistor including such a highly purified oxide semiconductor film is The capacitor has suppressed fluctuations in electrical characteristics and is electrically stable.

[0120] Note that when charges are trapped at the interface of the oxide semiconductor film, the threshold voltage of the transistor shifts (for example, if a positive charge is trapped on the back channel side, the The threshold voltage shifts in the negative direction. One of the causes of this charge trapping is the positive A model of the movement and trapping of on (or the atoms responsible for it) can be postulated. In a transistor using an oxide semiconductor, the cation source is The disclosed invention uses a highly purified oxide semiconductor, and Since this structure is in contact with the laminated structure of the metal oxide film and the insulating film, This even suppresses charge trapping due to hydrogen, which is expected in the case of a silicon dioxide film. The model is believed to be valid for a hydrogen ionization rate of, for example, about 10%.

[0121] As described above, a semiconductor device using an oxide semiconductor and having stable electrical characteristics can be provided. Therefore, a highly reliable semiconductor device can be provided.

[0122] As described above, the configurations, methods, etc. shown in this embodiment may be different from the configurations, methods, etc. shown in other embodiments. They can be used in appropriate combinations.

[0123] (Embodiment 2) A semiconductor device (display device) having a display function using the transistor described in Embodiment 1 as an example In addition, a part or the whole of a driver circuit including a transistor can be manufactured. The body can be integrally formed on the same substrate as the pixel portion to form a system-on-panel.

[0124] In FIG. 6A, a pixel portion 4002 provided on a first substrate 4001 is surrounded by a A sealant 4005 is provided thereon, and the substrate is sealed with a second substrate 4006. In (A), the area surrounded by the sealing material 4005 on the first substrate 4001 In a region different from the above, a single crystal semiconductor film or a polycrystalline semiconductor film is formed on a separately prepared substrate. A scanning line driver circuit 4004 and a signal line driver circuit 4003 are mounted. The signal line driver circuit 4003 and the scanning line driver circuit 4004 or the pixel portion 4002 are formed. The various signals and potentials are applied to the FPC (Flexible Printed Circuit). It is supplied by FPC4018a and FPC4018b.

[0125] In FIG. 6B and FIG. 6C, the pixel section 40 provided on the first substrate 4001 A sealant 4005 is provided so as to surround the gate electrode 4002 and the scanning line driver circuit 4004. In addition, a second substrate 4006 is provided on the pixel portion 4002 and the scanning line driver circuit 4004. Therefore, the pixel portion 4002 and the scanning line driver circuit 4004 are formed on the first substrate 400. The display element is sealed with a sealing material 4005 and a second substrate 4006. In FIG. 6B and FIG. 6C, the sealing material 4005 on the first substrate 4001 Therefore, a single crystal semiconductor film or a semiconductor film is formed on a separately prepared substrate in a region different from the region surrounded by the insulating film. A signal line driver circuit 4003 formed of a polycrystalline semiconductor film is mounted on the substrate 4001. 6C, a signal line driver circuit 4003 and a scanning line driver circuit 4004 are separately formed. Various signals and potentials given to the pixel portion 4002 or the FPC 4018 are is being supplied.

[0126] In addition, in FIG. 6(B) and FIG. 6(C), a signal line driver circuit 4003 is separately formed. 10, an example in which the scanning element 4001 is mounted on the first substrate 4001 is shown, but the present invention is not limited to this configuration. A signal line driver circuit may be formed separately and mounted, or a part of the signal line driver circuit or the scanning line driver circuit may be mounted. Only a part of the path may be formed separately and mounted.

[0127] The method of connecting the separately formed drive circuit is not particularly limited, and may be a COG (C Hip On Glass method, wire bonding method, or TAB (Tape On Glass) method The Automated Bonding method can be used. This is an example in which a signal line driver circuit 4003 and a scanning line driver circuit 4004 are implemented by the COG method. 6(B) shows an example in which a signal line driver circuit 4003 is mounted by the COG method. C) is an example in which the signal line driver circuit 4003 is mounted by the TAB method.

[0128] The display device includes a panel in which a display element is sealed, and a controller for the panel. This includes modules in which ICs, etc., including lasers, are mounted.

[0129] In this specification, the term "display device" refers to an image display device, a display device, or Refers to light sources (including lighting devices). Also refers to connectors such as FPC or TAB tape. or a module with TCP attached, a printed wiring board at the end of TAB tape or TCP A module with a display element or a display element with an IC (integrated circuit) directly mounted on it using the COG method. All installed modules are also included in the display device.

[0130] The pixel portion and the scanning line driver circuit provided on the first substrate include a plurality of transistors. The transistor shown as an example in Embodiment 1 can be applied to the semiconductor device.

[0131] Examples of display elements provided in the display device include liquid crystal elements (also called liquid crystal display elements), light-emitting elements, and the like. The light-emitting element can be a light-emitting display element. This category includes elements whose brightness is controlled by the light source, specifically inorganic EL (Electroluminescent) Luminescence, organic electroluminescence, etc. Also, electronic ink, etc. A display medium whose contrast changes depending on the action can also be applied.

[0132] One embodiment of a semiconductor device will be described with reference to FIGS. 7 to 9. (B) corresponds to the cross section at MN.

[0133] As shown in FIGS. 7 to 9, the semiconductor device has a connection terminal electrode 4015 and a terminal electrode 401. 6, and the connection terminal electrode 4015 and the terminal electrode 4016 are The terminal is electrically connected to the anisotropic conductive film 4019 .

[0134] The connection terminal electrode 4015 is formed from the same conductive film as the first electrode layer 4030. 4016 is a source electrode and a drain electrode of the transistor 4010 and the transistor 4011. It is made of the same conductive film as the electrodes.

[0135] A pixel portion 4002 and a scanning line driver circuit 4004 are provided on a first substrate 4001. 7 to 9, the transistors included in the pixel portion 4002 are 4004 and a transistor 4011 included in the scanning line driver circuit 4004. is doing.

[0136] In this embodiment, the transistors 4010 and 4011 are The transistor 4010 and the transistor 1 can be applied. 4011 has suppressed fluctuations in electrical characteristics and is electrically stable. As the semiconductor device of this embodiment shown in FIG. 9, a highly reliable semiconductor device can be provided. Cut.

[0137] The transistor 4010 provided in the pixel portion 4002 is electrically connected to a display element. The display element is not particularly limited as long as it can display an image, and various display elements can be used. can be used.

[0138] FIG. 7 shows an example of a liquid crystal display device using a liquid crystal element as a display element. The liquid crystal element 4013 includes a first electrode layer 4030, a second electrode layer 4031, and a The liquid crystal layer 4008 is sandwiched between insulating layers that function as alignment layers. The second electrode layer 4031 is provided on the second substrate 4 The first electrode layer 4030 and the second electrode layer 4031 are disposed on the liquid crystal layer 4008 side. The structure is such that the layers are stacked via a

[0139] The columnar spacers 4035 are obtained by selectively etching the insulating film. It is provided to control the film thickness (cell gap) of the layer 4008. A laser may also be used.

[0140] When liquid crystal elements are used as display elements, thermotropic liquid crystals, low molecular weight liquid crystals, polymer Liquid crystal, polymer dispersed liquid crystal, ferroelectric liquid crystal, antiferroelectric liquid crystal, etc. can be used. These liquid crystal materials can be in a cholesteric phase, smectic phase, cubic phase, or chromatic phase depending on the conditions. It shows an isotropic phase, an isotropic phase, etc.

[0141] Alternatively, a liquid crystal that exhibits a blue phase without using an alignment film may be used. When the temperature of the cholesteric liquid crystal is increased, the cholesteric phase transitions to the isotropic phase. The blue phase appears only in a narrow temperature range, so it is necessary to improve the temperature range. In order to improve the liquid crystal layer, a liquid crystal composition containing a chiral agent of several weight percent or more is used. A liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent has a response speed of 1 msec or less. Since the liquid crystal display is optically isotropic, no alignment treatment is required and the viewing angle dependency is small. Since there is no need to provide a facing film, rubbing treatment is also unnecessary. This can prevent electrostatic damage caused by the electrostatic discharge, thereby reducing defects and damage to the liquid crystal display device during the manufacturing process. Therefore, it is possible to improve the productivity of the liquid crystal display device.

[0142] The specific resistivity of the liquid crystal material is 1×10 9 Ω·cm or more, preferably 1×10 11 Ω·cm or more, and more preferably 1×10 12 Ω·cm or more. The specific resistivity values ​​in the specification are values ​​measured at 20°C.

[0143] The size of the storage capacitor provided in the liquid crystal display device is determined by the It is set so that the charge can be maintained for a predetermined period, taking into consideration the break current, etc. By using a transistor with a semiconductor film, the liquid crystal capacitance in each pixel It is sufficient to provide a storage volume having a size of 1 / 3 or less, preferably 1 / 5 or less, of the capacity of the do.

[0144] The transistor including the purified oxide semiconductor film used in this embodiment has an off-state Therefore, the current value (off-state current value) in the OFF state can be reduced. The signal retention time can be extended, and the write interval can also be set longer when the power is on. Therefore, the frequency of refresh operations can be reduced, which is effective in reducing power consumption. To bear fruit.

[0145] In addition, the transistor including the purified oxide semiconductor film used in this embodiment has the following characteristics: Since a relatively high field effect mobility can be obtained, high speed driving is possible. By using such a transistor in a pixel portion of a device, a high-quality image can be provided. In addition, the transistors are separately formed in a driver circuit portion and a pixel portion on the same substrate. This allows the number of components in the liquid crystal display device to be reduced.

[0146] There are two types of LCD displays: TN (Twisted Nematic) mode, IPS (In- Plane-Switching mode, FFS (Fringe Field Switching) mode tching) mode, ASM(Axially Symmetric aligned) Micro-cell) mode, OCB(Optical Compensated) Birefringence mode, FLC (Ferroelectric Liquid Crystal id Crystal) mode, AFLC (AntiFerroelectric Li You can use modes such as quid Crystal.

[0147] Furthermore, normally black type liquid crystal display devices, such as those employing vertical alignment (VA) mode, Here, the vertical alignment mode is a mode in which the liquid crystal display panel This is a method of controlling the alignment of liquid crystal molecules, and when no voltage is applied, In contrast to vertical alignment, the liquid crystal molecules are oriented vertically. For example, MVA (Multi-domain Vertical Alignment) ent) mode, PVA (Patterned Vertical Alignment ) mode, ASV (Advanced Super View) mode, etc. Also, a pixel can be divided into several regions (subpixels), and each Multi-domain or multi-domain design that allows molecules to bend in different directions A method called "

[0148] In addition, in display devices, black matrices (light-shielding layers), polarizing members, phase difference members, reflectors, Optical members (optical substrates) such as anti-reflection members are provided as appropriate. Circularly polarized light from a differential substrate may also be used. may also be used.

[0149] In addition, multiple light-emitting diodes (LEDs) are used as backlights to display the time-division information. It is also possible to use the field sequential driving method. By applying the char drive method, color display is possible without using a color filter. It is possible.

[0150] In addition, the display method in the pixel section uses the progressive method, interlace method, etc. In addition, the color elements controlled by pixels when displaying colors are RGB (R is red, G is green, and B is blue). For example, RGBW (W is white) ), or RGB plus one or more colors such as yellow, cyan, or magenta. The size of the display area may be different for each dot of the color element. The present invention is not limited to color display devices, but can also be applied to monochrome display devices. It can also be done as follows.

[0151] In addition, a light-emitting device using electroluminescence is used as a display element included in the display device. The light-emitting element using electroluminescence can be applied to a light-emitting material. They are classified according to whether the material is an organic compound or an inorganic compound. The latter is called an inorganic EL element.

[0152] In an organic EL element, when a voltage is applied to the light-emitting element, electrons and positive electrodes are released from a pair of electrodes. The holes are then injected into a layer containing a light-emitting organic compound, allowing a current to flow. The recombination of carriers (electrons and holes) causes light-emitting organic compounds to form excited states. The excited state is formed, and light is emitted when the excited state returns to the ground state. Such a light-emitting element is called a current-excited light-emitting element.

[0153] Inorganic EL elements are classified into dispersion-type inorganic EL elements and thin-film-type inorganic EL elements depending on the element structure. Dispersion-type inorganic EL elements have a light-emitting layer in which particles of light-emitting material are dispersed in a binder. The emission mechanism is a donor- The thin-film inorganic EL element is an acceptor recombination type luminescence element. The luminescent layer is sandwiched between dielectric layers. The structure is sandwiched between electrodes, and the light emission mechanism is the inner shell electron transition of the metal ion. This is a localized light emission that utilizes organic EL elements. do.

[0154] The light emitting element only needs to have at least one of the pair of electrodes transparent in order to extract light. Then, a transistor and a light emitting element are formed on the substrate, and light is emitted from the surface opposite to the substrate. Top emission, bottom emission, and light emission from the substrate side. There are light emitting elements with a double-sided emission structure that emits light from the side, and light emitting elements with any emission structure are suitable. It can be used.

[0155] Figure 8 shows an example of a light-emitting device using a light-emitting element as a display element. The transistor 4513 is electrically connected to the transistor 4010 provided in the pixel portion 4002. The light-emitting element 4513 includes a first electrode layer 4030, an electroluminescent layer 4511, a second electrode layer 4032, an electroluminescent layer 4513, a second electrode layer 4030, an electroluminescent layer 4511, a second electrode layer 4032 ... The electrode layer 4031 has a stacked structure, but is not limited to the structure shown. The configuration of the light emitting element 4513 can be changed appropriately according to the direction of the light to be extracted from the .

[0156] The partition wall 4510 is formed using an organic insulating material or an inorganic insulating material. An opening is formed on the first electrode layer 4030 using a resin material, and the sidewall of the opening is continuous. It is preferable to form the inclined surface with a certain curvature.

[0157] The electroluminescent layer 4511 may be composed of a single layer or a plurality of layers stacked. It doesn't matter whether it is completed or not.

[0158] The second electrode is formed to prevent oxygen, hydrogen, moisture, carbon dioxide, etc. from entering the light emitting element 4513. A protective film may be formed on the layer 4031 and the partition wall 4510. The protective film may be silicon nitride. Con film, silicon nitride oxide film, DLC (Diamond-Like Carbon) film, etc. In addition, the first substrate 4001, the second substrate 4006, and the sheet The space sealed by the sealing material 4005 is sealed with a filling material 4514. A protective film (laminating film) with high airtightness and low outgassing is used to prevent exposure to the outside air. packaging (enclosure) with a covering material (such as a protective film or ultraviolet curing resin film) is preferred.

[0159] Filler 4514 can be inert gas such as nitrogen or argon, or ultraviolet curing resin. Alternatively, thermosetting resins can be used, such as PVC (polyvinyl chloride), acrylic, and poly. Imide, epoxy resin, silicone resin, PVB (Polyvinyl Butyral) or EVA ( For example, if nitrogen is used as a filler, good.

[0160] If necessary, a polarizing plate or a circular polarizing plate (including an elliptical polarizing plate) may be attached to the light-emitting surface of the light-emitting element. ), retardation plates (λ / 4 plate, λ / 2 plate), color filters, and other optical films are provided as needed. Alternatively, an anti-reflection film may be provided on the polarizing plate or the circular polarizing plate. This allows for anti-glare treatment to be applied, which can diffuse reflected light and reduce glare.

[0161] It is also possible to provide electronic paper that drives electronic ink as a display device. Electronic paper is also called an electrophoretic display (electrophoretic display), It has the same readability as paper, consumes less power than other display devices, and can be made thin and light. This has the advantage that:

[0162] The electrophoretic display device may have various forms, but the first particles have a positive charge. and a second particle having a negative charge are mixed with a solvent or solute. By applying an electric field to the microcapsules, By moving the particles in the capsule in opposite directions, only the color of the particles that have gathered on one side is displayed. The first particles or the second particles contain a dye, and in the absence of an electric field, The first particle and the second particle are different in color (including colorless). (Mm).

[0163] In this way, electrophoretic displays are designed so that materials with high dielectric constants move to areas with high electric fields. This is a display that utilizes the so-called dielectrophoretic effect.

[0164] The microcapsules dispersed in a solvent are called electronic ink. This electronic ink can be printed on surfaces such as glass, plastic, fabric, and paper. Furthermore, color display is possible by using color filters or particles containing pigments.

[0165] The first particles and the second particles in the microcapsules are made of a conductive material and an insulating material. , semiconductor materials, magnetic materials, liquid crystal materials, ferroelectric materials, electroluminescent materials, A material selected from the group consisting of electrochromic materials, magnetophoretic materials, and composite materials of these. Just use

[0166] In addition, a display device using a twist ball display method can also be applied as electronic paper. The twist ball display method uses spherical particles painted in black and white as the display element. The electrode layer is disposed between the first electrode layer and the second electrode layer. A display method is performed by controlling the orientation of the spherical particles by generating a potential difference in the second electrode layer. It is the law.

[0167] FIG. 9 shows an active matrix electronic paper as one mode of a semiconductor device. The electronic paper of 9 is an example of a display device that uses the twisting ball display method.

[0168] A first electrode layer 4030 connected to the transistor 4010 and a second electrode layer 4031 provided on the second substrate 4006 A black region 4615a and a white region 4615b are formed between the second electrode layer 4031 and the A spherical particle 4613 is provided, which has a cavity 4612 filled with liquid around it. The spherical particles 4613 are filled with a filler 4614 such as resin. The electrode layer 4031 corresponds to a common electrode (opposite electrode). It is electrically connected to the wire.

[0169] 7 to 9, the first substrate 4001 and the second substrate 4006 are made of glass. In addition to the glass substrate, a flexible substrate can also be used. For example, a transparent plastic substrate can be used. As for plastic, FRP (Fibre Plastic) can be used. Ass-Reinforced Plastics) plate, PVF (Polyvinyl Fluoride) A film, a polyester film or an acrylic resin film can be used. In addition, aluminum foil is sandwiched between PVF film or polyester film. A port can also be used.

[0170] The insulating layer 4021 can be formed using an inorganic insulating material or an organic insulating material. In addition, acrylic resin, polyimide, benzocyclobutene resin, polyamide, epoxy resin The use of heat-resistant organic insulating materials such as those listed above is suitable for use as a planarizing insulating film. In addition to the above organic insulating materials, low-k materials, siloxane resins, and PSG (phosphorus glass), BPSG (borophosphorus glass), etc. can be used. The insulating layer may be formed by stacking a plurality of insulating films made of the above materials.

[0171] The method for forming the insulating layer 4021 is not particularly limited, and may be a sputtering method, Spin coating, dipping, spray coating, droplet ejection method (inkjet method, Roll coating, curing, offset printing, etc. can be applied. The insulating layer 4021 can also be formed by using ten-coating, knife coating, etc. do.

[0172] A display device transmits light from a light source or a display element to display an image. The thin films such as the substrate, insulating film, and conductive film provided in the pixel area are all in the visible light wavelength range. It is translucent to

[0173] A first electrode layer and a second electrode layer (a pixel electrode layer and a common electrode layer) that apply a voltage to the display element , counter electrode layer, etc.), the direction of the light to be extracted, the location of the electrode layer, The light transmission property or reflectivity can be selected depending on the pattern structure of the electrode layer.

[0174] The first electrode layer 4030 and the second electrode layer 4031 are made of indium containing tungsten oxide. oxide, indium zinc oxide with tungsten oxide, indium oxide with titanium oxide oxide, indium tin oxide containing titanium oxide, indium tin oxide (hereinafter referred to as ITO) ), indium zinc oxide, indium tin oxide doped with silicon oxide, etc. A conductive material having such a property can be used.

[0175] The first electrode layer 4030 and the second electrode layer 4031 are made of tungsten (W) and molybdenum (Mo). Mo, Zirconium (Zr), Hafnium (Hf), Vanadium (V), Niobium ( Nb), Tantalum (Ta), Chromium (Cr), Cobalt (Co), Nickel (Ni), Metals such as tungsten (Ti), platinum (Pt), aluminum (Al), copper (Cu), and silver (Ag) or its alloy or nitride thereof. can.

[0176] The first electrode layer 4030 and the second electrode layer 4031 are made of a conductive polymer (conductive polymer). The conductive polymer can be formed using a conductive composition containing a conductive polymer. For this purpose, a so-called π-electron conjugated conductive polymer can be used. For example, polyaniline or derivatives thereof, polypyrrole or derivatives thereof, polythiophene or derivatives thereof, Or a copolymer consisting of two or more of aniline, pyrrole and thiophene, or Derivatives and the like are included.

[0177] In addition, since transistors are easily damaged by static electricity, etc., a protective circuit for protecting the drive circuit is It is preferable to provide a path. The protection circuit is preferably constructed using a non-linear element.

[0178] As described above, by using the transistor described in Embodiment 1 as an example, a highly reliable semiconductor device can be obtained. The semiconductor device can be provided. Not only semiconductor devices with display functions, but also power devices mounted on power supply circuits, LSI semiconductor integrated circuits such as semiconductor devices with an image sensor function that reads information from an object, The present invention can be applied to semiconductor devices having various functions.

[0179] As described above, the configurations, methods, etc. shown in this embodiment may be different from the configurations, methods, etc. shown in other embodiments. They can be used in appropriate combinations.

[0180] (Embodiment 3) The semiconductor device disclosed in this specification can be applied to various electronic devices (including gaming machines). The electronic device can be, for example, a television device (television or television (also called digital receivers), computer monitors, digital cameras, digital video cameras cameras such as digital cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices) (c), portable game machines, personal digital assistants, audio playback devices, large game machines such as pachinko machines, etc. Examples of electronic devices including the liquid crystal display device described in the above embodiment include: I will explain.

[0181] FIG. 10A shows a notebook personal computer, which includes a main body 3001 and a housing 30 3002, a display unit 3003, a keyboard 3004, etc. Alternatively, by applying the semiconductor device described in Embodiment 2, a highly reliable notebook type It may be a personal computer.

[0182] FIG. 10B shows a personal digital assistant (PDA), and a main body 3021 includes a display unit 3023 and An external interface 3025 and operation buttons 3024 are provided. The stylus 3022 is an accessory for the function. By applying this semiconductor device, a more reliable personal digital assistant (PDA) can be achieved. This can be done.

[0183] FIG. 10C shows an example of an electronic book. For example, an electronic book 2700 has a housing 2 It consists of two housings, housing 2701 and housing 2703. 03 is integrated with a shaft portion 2711, and performs opening and closing operations around the shaft portion 2711. This configuration allows the device to operate like a paper book. .

[0184] The housing 2701 incorporates a display unit 2705, and the housing 2703 incorporates a display unit 2707. The display unit 2705 and the display unit 2707 are configured to display a continuous screen. Alternatively, a different screen may be displayed. For example, a text is displayed on the right display unit (display unit 2705 in FIG. 10C) and An image can be displayed on the display unit (display unit 2707 in FIG. 10C). By applying the semiconductor device shown in the first or second embodiment, a highly reliable electronic book can be obtained. The number of registered employees can be set at 2700.

[0185] FIG. 10C shows an example in which an operating unit and the like are provided in the housing 2701. For example, In the housing 2701, a power supply 2721, operation keys 2723, a speaker 2725, etc. The operation keys 2723 can be used to turn pages. A keyboard and a pointing device may be provided on one side. On the back or side of the device, there are external connection terminals (earphone terminal, USB terminal, etc.), a recording medium insertion port, etc. Furthermore, the electronic book 2700 may have a function as an electronic dictionary. It may also be configured so that

[0186] The electronic book 2700 may also be configured to be capable of transmitting and receiving information wirelessly. The desired book data can be purchased and downloaded from the electronic book server. It is also possible.

[0187] FIG. 10D shows a mobile phone, which is composed of two housings, a housing 2800 and a housing 2801. The housing 2801 contains a display panel 2802, a speaker 2803, a microphone Phone 2804, pointing device 2806, camera lens 2807, external connection The housing 2800 is provided with a terminal 2808 and the like. It is equipped with a solar cell 2810, an external memory slot 2811, etc. Also, an antenna is built in the housing 2801. By applying the device, a highly reliable mobile phone can be obtained.

[0188] The display panel 2802 is equipped with a touch panel, and the image displayed in FIG. The multiple operation keys 2805 are shown by dotted lines. A boost circuit is also implemented to boost the input voltage to the voltage required for each circuit.

[0189] The display direction of the display panel 2802 changes appropriately depending on the usage mode. The camera lens 2807 is located on the same surface as the lens 2802, allowing video calls. The speaker 2803 and microphone 2804 are not limited to voice calls, but are also used for video calls. Furthermore, the housing 2800 and the housing 2801 can be slid apart. , as shown in Figure 10(D), it can be folded from the unfolded state to the overlapped state, and it is portable. It is possible to make it smaller to suit the application.

[0190] The external connection terminal 2808 can be used to connect various cables such as an AC adapter and a USB cable. It is possible to charge the battery and to communicate data with a personal computer, etc. , a recording medium can be inserted into the external memory slot 2811 for storing and transferring a larger amount of data. We can handle it.

[0191] In addition to the above functions, it also has infrared communication functions, TV reception functions, etc. Good too.

[0192] FIG. 10(E) shows a digital video camera, which includes a main body 3051 and a display unit (A) 3057. , eyepiece 3053, operation switch 3054, display unit (B) 3055, battery 3056 The semiconductor device shown in the first or second embodiment is configured as follows. By using this, a highly reliable digital video camera can be obtained.

[0193] FIG. 10(F) shows an example of a television device. The television device 9600 is A display portion 9603 is incorporated in the housing 9601. The display portion 9603 displays images. In addition, the housing 9601 is supported by a stand 9605. The semiconductor device shown in the first or second embodiment is applied. This makes it possible to provide a highly reliable television device.

[0194] The television device 9600 can be operated using an operation switch provided on the housing 9601 or a separate remote control. This can be done by a remote control operation device. A display unit may be provided to display information output from the device.

[0195] The television device 9600 includes a receiver, a modem, and the like. It is possible to receive general television broadcasts, and also to receive wired or wireless signals via a modem. By connecting to a communication network, it can be one-way (sender to receiver) or two-way It is also possible to communicate information in both directions (between a sender and a receiver, or between receivers). .

[0196] As described above, the configurations, methods, etc. shown in this embodiment may be different from the configurations, methods, etc. shown in other embodiments. They can be used in appropriate combinations. [Explanation of symbols]

[0197] 110 Transistor 120 transistors 130 transistors 140 transistors 150 transistors 160 transistors 170 transistors 180 transistors 200 boards 202 insulating film 204 Metal oxide film 206 Oxide semiconductor film 208a Source electrode 208b Drain electrode 210 Metal oxide film 212 Gate insulating film 214 gate electrode 2700 e-books 2701 Case 2703 Housing 2705 ​​Display section 2707 Display section 2711 Shaft 2721 Power supply 2723 Operation Key 2725 Speaker 2800 chassis 2801 Case 2802 Display Panel 2803 Speaker 2804 Microphone 2805 Operation Key 2806 Pointing Device 2807 Camera lenses 2808 External connection terminal 2810 solar cell 2811 external memory slot 3001 main unit 3002 Case 3003 Display section 3004 Keyboard 3021 Main Unit 3022 stylus 3023 Display section 3024 Operation button 3025 External Interface 3051 Main Unit 3053 Eyepiece 3054 Operation switch 3055 Display section (B) 3056 Battery 3057 Display section (A) 4001 board 4002 Pixel section 4003 Signal line driver circuit 4004 Scanning line driver circuit 4005 Sealing material 4006 board 4008 Liquid crystal layer 4010 transistor 4011 transistor 4013 Liquid crystal element 4015 Connection terminal electrode 4016 Terminal electrode 4018 FPC 4018a FPC 4018b FPC 4019 Anisotropic conductive film 4021 Insulation layer 4030 Electrode layer 4031 Electrode layer 4032 Insulating film 4033 Insulating film 4035 Spacer 4510 Bulkhead 4511 Electroluminescent layer 4513 Light-emitting element 4514 Filling material 4612 Cavity 4613 Spherical particles 4614 Filling material 4615a Black area 4615b White area 9600 Television Equipment 9601 Housing 9603 Display section 9605 Stand

Claims

1. an insulating film on a substrate; a first oxide film having a region on the insulating film; a first conductive film having a region on the first oxide film; a second conductive film having a region on the first oxide film; an oxide semiconductor film having a region on the first oxide film; a second oxide film having a region on the oxide semiconductor film; a third conductive film having a region on the second oxide film, the insulating film includes silicon nitride; the second oxide film has the same material as the first oxide film; the oxide semiconductor film has a channel formation region of a transistor, the first conductive film has a region functioning as one of a source electrode and a drain electrode of the transistor, the second conductive film has a region that functions as the other of the source electrode and the drain electrode of the transistor, the third conductive film has a region that functions as a gate electrode of the transistor, the second oxide film has a region in contact with an upper surface of the oxide semiconductor film, the oxide semiconductor film has a region in contact with an upper surface of the first oxide film, the oxide semiconductor film has a region in contact with a top surface of the first conductive film and a region in contact with a side surface of the first conductive film; the oxide semiconductor film has a region in contact with a top surface of the second conductive film and a region in contact with a side surface of the second conductive film; the third conductive film has a region overlapping with the oxide semiconductor film with the second oxide film interposed therebetween; the second oxide film has a region that does not overlap with the third conductive film, the first conductive film has a region that does not overlap with the second oxide film, the second conductive film has a region that does not overlap with the second oxide film, an end portion of the second oxide film is disposed above the oxide semiconductor film in a cross-sectional view of the transistor taken along a channel length direction; a thickness of the first oxide film is greater than a thickness of the oxide semiconductor film; The semiconductor device, wherein the second oxide film has a thickness greater than that of the oxide semiconductor film.

2. an insulating film on a substrate; a first oxide film having a region on the insulating film; a first conductive film having a region on the first oxide film; a second conductive film having a region on the first oxide film; an oxide semiconductor film having a region on the first oxide film; a second oxide film having a region on the oxide semiconductor film; a third conductive film having a region on the second oxide film, the insulating film includes silicon nitride; the second oxide film has the same material as the first oxide film; the oxide semiconductor film has a channel formation region of a transistor, the first conductive film has a region functioning as one of a source electrode and a drain electrode of the transistor, the second conductive film has a region that functions as the other of the source electrode and the drain electrode of the transistor, the third conductive film has a region that functions as a gate electrode of the transistor, the second oxide film has a region in contact with an upper surface of the oxide semiconductor film, the oxide semiconductor film has a region in contact with an upper surface of the first oxide film, the oxide semiconductor film has a region in contact with a top surface of the first conductive film and a region in contact with a side surface of the first conductive film; the oxide semiconductor film has a region in contact with a top surface of the second conductive film and a region in contact with a side surface of the second conductive film; the third conductive film has a region overlapping with the oxide semiconductor film with the second oxide film interposed therebetween; the second oxide film has a region that does not overlap with the third conductive film, the first conductive film has a region that does not overlap with the second oxide film, the second conductive film has a region that does not overlap with the second oxide film, an end of the second oxide film is disposed above the oxide semiconductor film, and an end of the third conductive film is disposed above the second oxide film in a cross section of the transistor taken along a channel length direction; a thickness of the first oxide film is greater than a thickness of the oxide semiconductor film; The semiconductor device, wherein the second oxide film has a thickness greater than that of the oxide semiconductor film.

3. In claim 1 or claim 2, the first conductive film has a region overlapping with the oxide semiconductor film and a region not overlapping with the oxide semiconductor film, the second conductive film has a region overlapping with the oxide semiconductor film and a region not overlapping with the oxide semiconductor film.

Images