Semiconductor Devices

Abstract

To provide a semiconductor device including a capacitive element that has a high aperture ratio and is capable of increasing a capacitance value, and also to provide the semiconductor device low in manufacturing cost.SOLUTION: A semiconductor device includes: a transistor including a first oxide semiconductor film and a second oxide semiconductor film; and a capacitive element including an insulation film between a pair of electrodes. The transistor includes: the first oxide semiconductor film; a gate insulation film provided in contact with the first oxide semiconductor film; the second oxide semiconductor film provided in contact with the gate insulation film and provided at a position that overlaps with the first oxide semiconductor film; and a source electrode and a drain electrode which are connected to the first oxide semiconductor film. One of the pair of electrodes of the capacitive element is provided on the same surface as the second oxide semiconductor film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an article, a method, or a manufacturing method, or the present invention relates to a process, a machine, The present invention relates to a manufacture or composition of matter. The embodiments relate to a semiconductor device, a display device, an electronic device, a manufacturing method thereof, or a driving method thereof. In particular, one embodiment of the present invention relates to a semiconductor device having a transistor and a capacitor, Regarding the device. [Background technology]

[0002] It is used in many flat panel displays, such as liquid crystal displays and light-emitting displays. The transistors used are made of amorphous silicon and single-crystal silicon formed on a glass substrate. It is made of silicon semiconductor such as silicon or polycrystalline silicon. Transistors using silicon semiconductors are also used in integrated circuits (ICs).

[0003] In recent years, metal oxides that exhibit semiconductor properties have been used in transistors instead of silicon semiconductors. In this specification, metal oxides that exhibit semiconductor properties are referred to as oxides. For example, zinc oxide or In-Ga- A transistor using a Zn-based oxide is manufactured, and the transistor is used as a pixel switch of a display device. Techniques for use in chip elements and the like have been disclosed (see Patent Documents 1 and 2).

[0004] In order to increase the aperture ratio, a metal oxide film is provided on the same surface as the oxide semiconductor film of the transistor. The oxide semiconductor film and the pixel electrode connected to the transistor are provided at a predetermined distance from each other. A display device having such a capacitive element has been disclosed (see Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-123861 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-96055 [Patent Document 3] U.S. Patent No. 8,102,476 Summary of the Invention [Problem to be solved by the invention]

[0006] The capacitance element has a pair of electrodes and a dielectric film between them. The other electrode is a light-shielding electrode such as a gate electrode, source, or drain that constitutes a transistor. In many cases, the wiring is formed of a conductive film having a conductive property.

[0007] In order to increase the capacitance of the capacitor, the area occupied by the capacitor must be increased. Specifically, one measure is to increase the area where the pair of electrodes overlap. In a display device, a light-shielding conductive film is used to increase the area where a pair of electrodes overlap. If the area of ​​the conductive film is increased, the aperture ratio of the pixel decreases, and the display quality of the image deteriorates.

[0008] In view of the above, one aspect of the present invention is to provide a semiconductor device having a high aperture ratio and an increased capacitance value. Another object of the present invention is to provide a semiconductor device having a capacitor element that can One of the objects is to provide a semiconductor device that can be manufactured at low cost. One of the objectives is to provide a device.

[0009] The description of these problems does not preclude the existence of other problems. It is not necessary for one embodiment to solve all of these problems. The subject matter will be self-evident from the description, drawings, claims, etc. It is possible to extract other issues from the drawings, claims, etc. [Means for solving the problem]

[0010] One embodiment of the present invention is a transistor including a first oxide semiconductor film and a second oxide semiconductor film. a semiconductor device having a transistor and a capacitance element including an insulating film between a pair of electrodes, The transistor includes a first oxide semiconductor film and a gate insulating film provided in contact with the first oxide semiconductor film. a gate insulating film provided in contact with the first oxide semiconductor film and overlapping the first oxide semiconductor film; a second oxide semiconductor film formed on the first oxide semiconductor film and a source electrode and a drain electrode connected to the first oxide semiconductor film; and a capacitor element having a pair of electrodes, one of which is on the same surface as the second oxide semiconductor film. The semiconductor device is characterized in that

[0011] Another embodiment of the present invention is a semiconductor device including a first oxide semiconductor film and a second oxide semiconductor film. and a capacitor element including an insulating film between a pair of electrodes. The transistor has a gate electrode including the second oxide semiconductor film and a gate electrode on the gate electrode. an insulating film, a first oxide semiconductor film on the gate insulating film at a position overlapping with the gate electrode; a source electrode and a drain electrode over the oxide semiconductor film; a second oxide semiconductor film formed on the same surface as the first oxide semiconductor film; be.

[0012] Another embodiment of the present invention is a semiconductor device including a first oxide semiconductor film and a second oxide semiconductor film. and a capacitor element including an insulating film between a pair of electrodes. The transistor includes a first oxide semiconductor film, a source electrode on the first oxide semiconductor film, and a a drain electrode, a gate insulating film on the first oxide semiconductor film, and a first a gate electrode including a second oxide semiconductor film in a position overlapping with the oxide semiconductor film; One of the pair of electrodes of the capacitor is provided on the same surface as the second oxide semiconductor film. This is a semiconductor device characterized by the above.

[0013] In each of the above structures, the other of the pair of electrodes of the capacitor is formed of the first oxide semiconductor film. It is preferable that the capacitor element is provided on the same surface. This is preferable.

[0014] In each of the above structures, the first oxide semiconductor film and the second oxide semiconductor film are made of In. -M-Zn oxide (M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn or H It is preferable that the formula (f) is used.

[0015] Further, one embodiment of the present invention also includes a display device and an electronic device using the semiconductor device having any of the above structures. It can be enjoyed. [Effects of the Invention]

[0016] According to one embodiment of the present invention, there is provided a capacitor element having a high aperture ratio and capable of increasing a capacitance value. Furthermore, a semiconductor device having a low manufacturing cost can be provided. Alternatively, a novel semiconductor device or the like can be provided.

[0017] The description of these effects does not preclude the existence of other effects. An embodiment does not necessarily have to have all of these effects. The above will be made clear from the description, drawings, claims, etc. It is possible to extract other effects from the descriptions in the aspects and claims. [Brief explanation of the drawings]

[0018] [Figure 1] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 2] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 3] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 4] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 5] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 6] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 7] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 8] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 9] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 10] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 11] 1A and 1B are a cross-sectional view and a band diagram illustrating one embodiment of a semiconductor device. [Figure 12] 1A and 1B are a block diagram and a circuit diagram illustrating a display device. [Figure 13] FIG. 2 is a diagram illustrating a display module. [Figure 14] 1A to 1C illustrate electronic devices. [Figure 15] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 16] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 17] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 18] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 19] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 20] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 21] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 22] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. One embodiment is not limited to the following description, and the present invention may be modified without departing from the spirit and scope of the present invention. It will be readily apparent to those skilled in the art that various changes in form and details may be made. One aspect of the invention should not be construed as being limited to the description of the following embodiment. In the embodiments described below, the same parts or parts having similar functions are referred to as The same symbols or hatch patterns are used in common among different drawings, and their repetition The explanation will be omitted.

[0020] In each drawing described in this specification, the size of each component, the thickness of the film, or the area is not clearly indicated. The figures may be exaggerated for clarity and are not necessarily limited to that scale. .

[0021] In addition, ordinal numbers such as first and second used in this specification are used in order to avoid confusion of elements. It is not intended to limit the number of items. The terms "second" or "third" can be used interchangeably to explain the present invention.

[0022] The functions of the "source" and "drain" of a transistor are different for transistors of different polarities. When using a current source, or when the direction of the current changes during circuit operation, For this reason, in this specification, the terms "source" and "drain" are used interchangeably. It can be used as such.

[0023] (Embodiment 1) In this embodiment, a semiconductor device of one embodiment of the present invention will be described with reference to FIGS. do.

[0024] <Configuration example of semiconductor device> FIG. 1A is a top view of a semiconductor device of one embodiment of the present invention, and FIG. 1B is a top view of a semiconductor device of FIG. ) corresponds to the cross-sectional view of the cut surface between the dashed dotted line AB and the dashed dotted line CD. In FIG. 1A, in order to avoid complication, only some of the components of the semiconductor device (gate) are shown. The illustration omits the gate insulating film, etc.

[0025] The semiconductor device illustrated in FIGS. 1A and 1B includes a first oxide semiconductor film 110a and a second oxide semiconductor film 110b. A transistor 150 including a compound semiconductor film 104a and a capacitor including an insulating film between a pair of electrodes. In the capacitor 160, one of a pair of electrodes is a second oxide. a second oxide semiconductor film 104b on the same plane as the oxide semiconductor film 104a; The other is a first oxide semiconductor film 110b on the same plane as the first oxide semiconductor film 110a. be.

[0026] The transistor 150 has a gate electrode including a second oxide semiconductor film 104a on a substrate 102. and a gate insulating film on the gate electrode including the second oxide semiconductor film 104a. The insulating film 108 and the gate electrode including the second oxide semiconductor film 104a on the insulating film 108 overlap each other. The first oxide semiconductor film 110a at the position where the first oxide semiconductor film 110a is to be folded and the source on the first oxide semiconductor film 110a are In other words, the transistor 150 has a source electrode 112a and a drain electrode 112b. The first oxide semiconductor film 110a and the second oxide semiconductor film 110b are provided in contact with each other. an insulating film 108 which functions as a gate insulating film; a second oxide semiconductor film 104a provided so as to overlap with the oxide semiconductor film 110a; The source electrode 112a and the drain electrode 112b are connected to the first oxide semiconductor film 110a. Note that the transistor 150 shown in FIGS. It is a hexagonal structure.

[0027] Note that the first oxide semiconductor film 110a functions as a channel region of the transistor 150. The second oxide semiconductor film 104a can be used as a gate electrode of the transistor 150. Therefore, the second oxide semiconductor film 104 functions as a gate insulating film rather than the first oxide semiconductor film 110a. The resistivity of the first oxide semiconductor film 110a and the second oxide semiconductor film 104a is low. The first oxide semiconductor film 110a and the second oxide semiconductor film 110b preferably contain the same metal element. By configuring the compound semiconductor film 104a to have the same metal element, It is possible to share the same equipment (film equipment, processing equipment, etc.), thereby reducing manufacturing costs. can be done.

[0028] Therefore, the transistor 150 includes the first oxide semiconductor film 110a and the first oxide The insulating film 108 is in contact with the semiconductor film 110a. The first oxide semiconductor film 110a is in contact with the insulating film 108. and a second oxide semiconductor film 104a overlapping with the first oxide semiconductor film 110a. The oxide semiconductor film 110a and the second oxide semiconductor film 104a contain the same metal element, and the first oxide semiconductor film 110a and the second oxide semiconductor film 104a contain the same metal element. The resistivity of the second oxide semiconductor film 104a is lower than that of the semiconductor film 110a.

[0029] In addition, wirings or the like formed of a separate metal film or the like are formed on the second oxide semiconductor films 104a and 104b. For example, the semiconductor device shown in FIG. When used in a capacitor element, the lead wiring or gate wiring is formed of a metal film, and the metal The second oxide semiconductor films 104a and 104b may be connected to the first oxide semiconductor film 104a. By forming the wiring or gate wiring etc. with a metal film, the wiring resistance can be reduced. This makes it possible to suppress signal delays and the like.

[0030] In addition, on the transistor 150, more specifically, the first oxide semiconductor film 110a, the source Insulating films 114, 116, and 118 are formed on the electrode 112a and the drain electrode 112b. The insulating films 114, 116, and 118 function as protective insulating films for the transistor 150. It has.

[0031] The capacitor 160 is a second capacitor having a function as one of a pair of electrodes on the substrate 102. and a dielectric film on the first oxide semiconductor film 104b. a portion overlapping with the second oxide semiconductor film 104b with the insulating film 108 interposed therebetween; a first oxide semiconductor film 110b that functions as the other electrode of the pair of electrodes; In addition, a protective film is formed on the capacitor 160, more specifically, on the first oxide semiconductor film 110b. An insulating film 118 that functions as an insulating film is formed.

[0032] As described above, the insulating film 108 serves as a gate insulating film in the transistor 150. In the capacitance element 160, it functions as a dielectric film. In this example, the insulating film 108 has a laminated structure of an insulating film 106 and an insulating film 107. However, one embodiment of the present invention is not limited thereto. The insulating film 108 may have a single-layer structure or a stack of three or more layers. It may also have a layered structure.

[0033] The capacitor 160 has a light-transmitting property. The first oxide semiconductor film 110b, the second oxide semiconductor film 104b, and the insulating film 108 are Each of them is made of a light-transmitting material. By doing so, it can be formed in a large area in a region other than where the transistor in the pixel is formed. Therefore, it is possible to obtain a semiconductor device having an increased aperture ratio and an increased capacitance value. As a result, a semiconductor device with excellent display quality can be obtained. 0 can be manufactured by using the manufacturing process of the transistor 150. A semiconductor device can be obtained with low manufacturing costs.

[0034] Note that the insulating film 106 used for the transistor 150 and the capacitor 160 and the The insulating film 118 provided on the capacitor 150 and the capacitor element 160 is made of a material containing at least hydrogen. In addition, the insulating film 10 used for the transistor 150 and the capacitor 160 7, and insulating films 114 and 116 provided over the transistor 150 and the capacitor 160 As the insulating film, an insulating film containing at least oxygen is used. The insulating film used for the capacitor 160 and the insulating film used over the transistor 150 and the capacitor 160 By using the insulating film having the above structure as the insulating film, the transistor 150 and the capacitor Controlling the resistivity of the first oxide semiconductor film and the second oxide semiconductor film included in 160 can be done.

[0035] Specifically, in the transistor 150, the first oxide semiconductor film 110a has a channel The first oxide semiconductor film 110b and the second oxide semiconductor film 104 are used as a gate region. On the other hand, the first oxide semiconductor film 110b and the second oxide semiconductor film 104b have higher resistivity than the first oxide semiconductor film 110a and the second oxide semiconductor film 104b. The oxide semiconductor films 104a and 104b function as electrodes. It has a lower resistivity than the conductive film 110a.

[0036] Here, the first oxide semiconductor films 110a and 110b and the second oxide semiconductor film 104 The method for controlling the resistivity of 104a and 104b will be described below.

[0037] <Method for controlling the resistivity of oxide semiconductors> The first oxide semiconductor films 110a and 110b and the second oxide semiconductor films 104a and 104b are The oxide semiconductor film that can be used for 4b has oxygen vacancies and / or hydrogen or water vacancies in the film. It is a semiconductor material whose resistivity can be controlled by the impurity concentration of the above. The first oxide semiconductor films 110a and 110b and the second oxide semiconductor films 104a and 104b b) Treatment that increases oxygen deficiency and / or impurity concentration, or By selecting a process that reduces the degree of oxidation, it is possible to The resistivity of the membrane can be controlled.

[0038] Specifically, the second oxide semiconductor film 110 functions as a gate electrode of the transistor 150. 104a, a second oxide semiconductor film 104b serving as an electrode of the capacitor 160, and a capacitor An oxide semiconductor film used for the first oxide semiconductor film 110b functioning as an electrode of the element 160 and / or By increasing impurities such as hydrogen and water in the oxide semiconductor film, the carrier density is increased. In addition, when the oxide semiconductor film contains hydrogen, the oxide semiconductor film can have low resistivity. and forming an insulating film containing hydrogen in contact with the oxide semiconductor film, and diffusing hydrogen from the insulating film containing hydrogen into the oxide semiconductor film. As a result, an oxide semiconductor film with high carrier density and low resistivity can be obtained.

[0039] On the other hand, the first oxide semiconductor film 110 functioning as a channel region of the transistor 150 a) is formed by providing the insulating films 107, 114, and 116, and the insulating film 106 containing hydrogen, At least one of the insulating films 107, 114, and 116 is not in contact with the insulating film 118. In other words, by applying an insulating film that can release oxygen, the first Oxygen can be supplied to the oxide semiconductor film 110a. The semiconductor film 110a is an oxide semiconductor film in which oxygen vacancies in the film or at the interface are compensated for and which has high resistivity. The insulating film capable of releasing oxygen includes, for example, a silicon oxide film, Alternatively, a silicon oxynitride film can be used.

[0040] In order to obtain an oxide semiconductor film with low resistivity, an ion implantation method, an ion doping method, etc. , plasma immersion ion implantation method, etc. Nitrogen or nitrogen may be implanted into the oxide semiconductor film.

[0041] In order to obtain an oxide semiconductor film with low resistivity, the oxide semiconductor film is subjected to plasma treatment. For example, the plasma treatment may be carried out using a rare gas (He, Ne, A Plasma treatment using a gas containing one selected from the group consisting of r, Kr, and Xe), hydrogen, and nitrogen. More specifically, plasma treatment under an Ar atmosphere, a mixed gas of Ar and hydrogen, Plasma treatment under Ar atmosphere, plasma treatment under ammonia atmosphere, Ar and ammonia Examples of suitable plasma treatment methods include plasma treatment in a mixed gas atmosphere of 1000 ppm or 1000 ppm, or plasma treatment in a nitrogen atmosphere. can be done.

[0042] By the plasma treatment, the oxide semiconductor film is formed into a lattice from which oxygen is desorbed (or This creates oxygen vacancies in the separated areas. These oxygen vacancies can be a cause of carrier generation. In addition, in the vicinity of the oxide semiconductor film, more specifically, under or When hydrogen is supplied from the insulating film in contact with the upper side, the oxygen vacancies and hydrogen combine to form In some cases, electrons are generated as carriers.

[0043] On the other hand, an oxide semiconductor film in which oxygen vacancies are filled and the hydrogen concentration is reduced can be made highly purified and intrinsic. Alternatively, it can be said that the oxide semiconductor film is substantially highly purified and made intrinsic. The carrier density of the oxide semiconductor film is 1×10 17 pieces / cm 3 preferably less than 1×10 13 pieces / cm3 more preferably less than 1×10 -9 pieces / cm 3 End 1×10 11 pieces / cm 3 High purity or substantially high purity Some oxide semiconductor films have a small number of carrier generation sources, and therefore the carrier density can be reduced. In addition, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a high density of defect states. Since the concentration is low, the trap state density can be reduced.

[0044] In addition, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a significantly low off-state current. Very small, with a channel width of 1×10 6 Even if the device has a channel length L of 10 μm, When the voltage between the source and drain electrodes (drain voltage) is in the range of 1V to 10V, The off-current is below the measurement limit of the semiconductor parameter analyzer, i.e., 1×10 -13 Below A Therefore, the above-mentioned high purity intrinsic or substantially high purity The first oxide semiconductor film 110a, which is an intrinsic oxide semiconductor film, is used for the channel region. The transistor 150 thus obtained has small fluctuations in electrical characteristics and is highly reliable.

[0045] The insulating film 106 may be, for example, an insulating film containing hydrogen, in other words, capable of releasing hydrogen. The second oxide semiconductor film 104a is formed by using a suitable insulating film, typically a silicon nitride film. , hydrogen can be supplied to 104b. By using an insulating film containing hydrogen like the film 106, hydrogen can be easily absorbed into the first oxide semiconductor film 110b. The insulating film capable of releasing hydrogen is a film containing water. The element concentration is 1×10 22 atoms / cm 3 It is preferable that the insulating film is more than or equal to the above. The second oxide semiconductor film 104a and the second oxide semiconductor film 104b are formed in contact with the first oxide semiconductor film 110b. As a result, the second oxide semiconductor films 104a and 104b and the first oxide semiconductor film 110 In this way, hydrogen can be effectively contained in the second oxide semiconductor film 104 b. a, 104b, and the insulating film in contact with the first oxide semiconductor film 110b. This makes it possible to control the resistivity of the oxide semiconductor film.

[0046] The hydrogen contained in the oxide semiconductor film reacts with oxygen that is bonded to metal atoms to form water. The oxygen vacancies are formed in the lattice from which oxygen is desorbed (or in the portions from which oxygen is desorbed). When hydrogen enters the electron carrier, it can generate electrons. By bonding with oxygen, which bonds with metal atoms, electrons, which act as carriers, may be generated. Therefore, the second oxide semiconductor film 104 provided in contact with the insulating film containing hydrogen a, 104b, and the first oxide semiconductor film 110b are thicker than the first oxide semiconductor film 110a. Therefore, the oxide semiconductor film has a high carrier density.

[0047] The first oxide semiconductor film 110a in which the channel region of the transistor 150 is formed is It is preferable that the amount of the element is reduced as much as possible. In 0a, secondary ion mass spectrometry (SIMS) The hydrogen concentration obtained by spectrometry was calculated as 2×10 20 atoms / cm 3 Less than or equal to 5 x 10 19atoms / cm 3 Less than or equal to 1×10 19 atoms / cm 3 Below, 5 x 10 18 atoms / cm 3 Less than 1x1 0 18 atoms / cm 3 Less than or equal to 5 × 10 17 atoms / cm 3 below, More preferably, 1 × 10 16 atoms / cm 3 The following applies.

[0048] On the other hand, a second electrode functioning as the gate electrode of the transistor 150 and the electrode of the capacitor 160 The oxide semiconductor films 104a and 104b and the oxide semiconductor film 104a functioning as electrodes of the capacitor 160 are The conductive film 110b has a lower hydrogen concentration and / or a lower amount of oxygen vacancies than the first oxide semiconductor film 110a. The oxide semiconductor film has a high content of SiO 2 and low resistivity.

[0049] In addition, the first oxide semiconductor films 110a and 110b, the second oxide semiconductor film 104a, The first oxide semiconductor films 110a and 110b and the second oxide semiconductor films 104b contain the same metal element. The oxide semiconductor films 104a and 104b contain the same metal element. However, the first oxide semiconductor films 110a and 110b are preferably formed by the above-mentioned method because the manufacturing cost can be reduced. The second oxide semiconductor films 104a and 104b have different compositions even if they contain the same metal element. For example, during the manufacturing process of a transistor or a capacitor, the metal element in the film may be different. The elements may be released, resulting in a different metal composition.

[0050] As described above, in the semiconductor device according to one embodiment of the present invention, In other words, a conductive film that functions as an electrode of a capacitor element and a conductive film that functions as an electrode of a capacitor element are simultaneously formed. a conductive film serving as a gate electrode of a transistor and a conductive film serving as an electrode of a capacitor element; By forming the conductive film on the same surface, it is possible to reduce manufacturing costs. A conductive film that functions as a gate electrode of a transistor and a conductive film that functions as an electrode of a capacitor element The film includes an oxide semiconductor film. By performing appropriate treatment on the oxide semiconductor film, A conductive film having low resistivity and light-transmitting properties can be obtained. The transistor and / or the capacitor can be made light-transmitting.

[0051] Here, the details of other components of the semiconductor device shown in FIGS. 1(A) and 1(B) are as follows: The explanation is given below.

[0052] <Substrate> There is no particular restriction on the material of the substrate 102, but it should be strong enough to withstand the subsequent heat treatment. For example, glass substrates, ceramic substrates, quartz substrates, and A fire substrate or the like may be used as the substrate 102. Also, silicon or silicon carbide may be used as the material. Single crystal semiconductor substrates, polycrystalline semiconductor substrates, compound semiconductors such as silicon germanium, etc. It is also possible to apply a substrate, an SOI substrate, etc., and a semiconductor element is provided on these substrates. The substrate 102 may be a glass substrate. If you are using 6th generation (1500mm x 1850mm), 7th generation (1870mm x 220 0mm), 8th generation (2200mm x 2400mm), 9th generation (2400mm x 280 By using large area substrates such as 10th generation (2950mm x 3400mm), A large display device can be manufactured. In addition, a flexible substrate is used as the substrate 102. The transistor 150, the capacitor 160, and the like may be formed directly on a flexible substrate.

[0053] In addition to these, various substrates can be used as the substrate 102 to form transistors. The type of substrate is not limited to a specific one. Plastic substrate, metal substrate, stainless steel substrate, stainless steel foil Substrate with tungsten foil, tungsten substrate, substrate with tungsten foil, flexible substrate, Examples include laminated films, paper containing fibrous materials, and base films. Glass substrates Examples of such glass include barium borosilicate glass, aluminoborosilicate glass, and soda glass. An example of a flexible substrate is polyethylene terephthalate (PE T), polyethylene naphthalate (PEN), and polyethersulfone (PES) are typical examples. These include plastics that can be used for bonding, and flexible synthetic resins such as acrylic. Examples of the film include polypropylene, polyester, polyvinyl fluoride, or poly Examples of base films include polyester, polyamide, and poly Imide, inorganic vapor deposition film, paper, etc. In particular, semiconductor substrates, single crystal substrates, By manufacturing transistors using SOI substrates, etc., characteristics, size, or shape can be improved. To manufacture transistors with small size, high current capacity, and little variation in By configuring a circuit using such transistors, it is possible to reduce the power consumption of the circuit, This allows for high integration of circuits.

[0054] It is also possible to form a transistor using a certain substrate and then transfer the transistor to another substrate. The transistor may be placed on one of the substrates to which the transistor is transferred. Examples include substrates on which the above-mentioned transistors can be formed, as well as paper substrates, ceramic substrates, and the like. Fan substrate, stone substrate, wood substrate, fabric substrate (natural fibers (silk, cotton, hemp), synthetic fibers (nylon) , polyurethane, polyester) or regenerated fiber (acetate, cupra, rayon, These substrates include recycled polyester, leather substrates, and rubber substrates. By using this, it is possible to form transistors with good characteristics and low power consumption. This allows for the manufacture of devices that are less likely to break, more heat resistant, lighter in weight, or thinner.

[0055] <First Oxide Semiconductor Film and Second Oxide Semiconductor Film> The first oxide semiconductor films 110a and 110b and the second oxide semiconductor films 104a and 104b are 4b is at least indium (In), zinc (Zn) and M (Al, Ti, Ga, Y, In-M-Zn oxide containing metals such as Zr, La, Ce, Sn, or Hf It is preferable that the oxide film contains both In and Zn. In order to reduce the variations in the electrical characteristics of transistors using oxide semiconductors, It is preferable to include a stabilizer.

[0056] The stabilizer includes the metals described above under M, for example, gallium (Ga), silicon (Si), and the like. Sn, hafnium (Hf), aluminum (Al), or zirconium (Zr) Other stabilizers include lanthanum (La), a lanthanide. , Cerium (Ce), Praseodymium (Pr), Neodymium (Nd), Samarium (Sm), Europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium ( Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc.

[0057] The first oxide semiconductor films 110a and 110b and the second oxide semiconductor films 104a and 104b are Examples of oxide semiconductors constituting 4b include In-Ga-Zn oxides, In-Al- Zn-based oxide, In-Sn-Zn-based oxide, In-Hf-Zn-based oxide, In-La-Z n-based oxides, In-Ce-Zn-based oxides, In-Pr-Zn-based oxides, In-Nd-Zn oxides, In-Sm-Zn oxides, In-Eu-Zn oxides, In-Gd-Zn oxides Oxides, In-Tb-Zn oxides, In-Dy-Zn oxides, In-Ho-Zn oxides oxides, In-Er-Zn oxides, In-Tm-Zn oxides, In-Yb-Zn oxides In-Lu-Zn ​​oxides, In-Sn-Ga-Zn oxides, In-Hf-Ga- Zn-based oxides, In-Al-Ga-Zn-based oxides, In-Sn-Al-Zn-based oxides, I n-Sn-Hf-Zn oxide and In-Hf-Al-Zn oxide can be used .

[0058] Here, the In-Ga-Zn oxide refers to an oxide having In, Ga, and Zn as its main components. The ratio of In, Ga, and Zn does not matter. Metal elements other than n may be included.

[0059] In addition, the first oxide semiconductor films 110a and 110b, the second oxide semiconductor film 104a, The first oxide semiconductor film 110 contains the same metal element as the oxides. the second oxide semiconductor films 104a and 104b are made of the same metal element; For example, a metal oxide target having the same metal composition can be manufactured by By using a metal oxide having the same metal composition, the manufacturing cost can be reduced. By using an oxide target, the etching gas used for processing an oxide semiconductor film can be The etching solution can be commonly used.

[0060] <Insulating film> The insulating film functions as a gate insulating film of the transistor 150 and a dielectric film of the capacitor element 160. The insulating films 106 and 107 are formed by depositing silicon oxide by plasma CVD, sputtering, or the like. Silicon oxide film, silicon oxynitride film, silicon nitride oxide film, silicon nitride film, aluminum oxide film, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, acid tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film and neodymium oxide film The insulating layers 106 and 107 may each be made of one or more insulating materials. Instead of using the laminated structure of 7, a single insulating layer selected from the above-mentioned materials may be used.

[0061] Note that the first oxide semiconductor film 110 functioning as a channel region of the transistor 150 The insulating film 107 in contact with a is preferably an oxide insulating film, and has a composition other than the stoichiometric composition. It is more preferable to have a region containing excess oxygen (oxygen excess region). The insulating film 107 is an insulating film that can release oxygen. To provide the excess region, for example, the insulating film 107 may be formed in an oxygen atmosphere. Alternatively, oxygen may be introduced into the insulating film 107 after it has been formed to form an oxygen-excess region. The implantation methods include ion implantation, ion doping, and plasma immersion ion implantation. For example, a method such as a plasma treatment can be used.

[0062] Furthermore, when hafnium oxide is used for the insulating films 106 and 107, the following effects are achieved. Hafnium oxide has a higher dielectric constant than silicon oxide and silicon oxynitride. Therefore, the physical film thickness can be made larger than the equivalent oxide film thickness, so the equivalent oxide film thickness can be increased to 10n. Even when the thickness is set to 100 μm or less or 5 nm or less, the leakage current due to the tunnel current can be reduced. That is, a transistor with a small off-state current can be realized. Hafnium oxide having a crystalline structure has a higher Therefore, in order to make a transistor with a small off-state current, the crystal structure It is preferable to use hafnium oxide having a crystal structure. Examples of the crystal structure include monoclinic and However, one embodiment of the present invention is not limited to these.

[0063] In this embodiment, a silicon nitride film is formed as the insulating film 106, and the insulating film 107 The silicon nitride film has a lower dielectric constant than the silicon oxide film. The film thickness required to obtain the same capacitance as a silicon oxide film is large, so The insulating film 108 functions as a gate insulating film of the transistor 150 and a dielectric film of the capacitor element 160. By including a silicon nitride film, the insulating film can be physically thickened. , the decrease in the breakdown voltage of the transistor 150 and the capacitance element 160 is suppressed, and further, the breakdown voltage is increased. Therefore, electrostatic damage to the transistor 150 and the capacitor 160 can be suppressed. .

[0064] <Source and drain electrodes> Materials that can be used for the source electrode 112a and the drain electrode 112b include: Aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum Elemental metals consisting of tantalum, silver, tantalum, or tungsten, or alloys containing these as the main components Gold can be used as a single layer or as a laminated structure. For example, a thin film of titanium on an aluminum film. Two-layer structure with titanium film laminated on tungsten film, two-layer structure with titanium film laminated on tungsten film, molybdenum Two-layer structure with copper film laminated on silicon film, and copper film laminated on alloy film containing molybdenum and tungsten. a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film; A titanium film or a titanium nitride film and an aluminum film overlaid on the titanium film or the titanium nitride film. A three-layer structure in which a titanium film or titanium nitride film is formed on top of a titanium or copper film. Molybdenum film or molybdenum nitride film and the molybdenum film or molybdenum nitride film An aluminum film or copper film is layered on top, and a molybdenum film or nitride film is then layered on top of that. There are also three-layer structures in which a molybdenum film is formed. When the electrode 112b has a three-layer structure, the first and third layers are made of titanium, titanium nitride, molybdenum, and the like. Molybdenum, tungsten, alloys containing molybdenum and tungsten, molybdenum and zirconium The second layer is made of an alloy containing copper, aluminum, or gold. Alternatively, it is preferable to form a film made of a low resistance material such as silver or an alloy of copper and manganese. Note that a transparent conductive material containing indium oxide, tin oxide, or zinc oxide may also be used. The materials that can be used for the source electrode 112a and the drain electrode 112b are, for example, The film can be formed by a sputtering method.

[0065] <Protective insulating film> The insulating films 114, 116, and 118 functioning as protective insulating films for the transistor 150 and the capacitor The insulating film 118 that functions as a protective insulating film for the capacitor 160 can be formed by plasma CVD, By sputtering or the like, a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, Silicon nitride film, aluminum oxide film, hafnium oxide film, yttrium oxide film, dioxide film ZrO2 film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film Insulating layers containing one or more of a cerium oxide film and a neodymium oxide film can be used. can.

[0066] Note that in the capacitor 160, the insulating film 118 functions as an electrode of the capacitor 160. The insulating layer also has a function of reducing the resistivity of the first oxide semiconductor film 110b.

[0067] In addition, the first oxide semiconductor film 110 serving as a channel region of the transistor 150 The insulating film 114 in contact with a is preferably an oxide insulating film that can release oxygen. In other words, an insulating film capable of releasing oxygen is an insulating film having a stoichiometric composition. It is an insulating film that has a region (oxygen excess region) that contains more oxygen than the insulating composition. To provide an oxygen excess region in the film 114, for example, the insulating film 114 is formed in an oxygen atmosphere. Alternatively, oxygen may be introduced into the insulating film 114 after it is formed to form an oxygen-excess region. The oxygen introduction method includes ion implantation, ion doping, plasma imaging, and the like. The ion implantation method, plasma treatment, etc. can be used.

[0068] By using an insulating film capable of releasing oxygen as the insulating film 114, Oxygen is transferred to the first oxide semiconductor film 110a which functions as a channel region of the capacitor 150. Therefore, the amount of oxygen vacancies in the first oxide semiconductor film 110a can be reduced. The surface temperature is 100°C or higher and 700°C or lower, preferably 100°C or higher and 500°C or lower. The oxygen content measured by thermal desorption spectroscopy (hereinafter referred to as TDS analysis) is The amount of molecules released is 1.0 × 10 18 molecules / cm 3 By using the above insulating film, the first The amount of oxygen vacancies in the oxide semiconductor film 110a can be reduced.

[0069] The thickness of the insulating film 114 is 5 nm or more and 150 nm or less, preferably 5 nm or more and 50 nm or less. The thickness of the insulating film 116 can be set to 10 nm or less, preferably 10 nm or more and 30 nm or less. The thickness is 30 nm or more and 500 nm or less, preferably 150 nm or more and 400 nm or less. This can be done.

[0070] In addition, the insulating films 114 and 116 can be made of the same material, so that the insulating film In some cases, the interface between the film 114 and the insulating film 116 cannot be clearly seen. In this embodiment, the interface between the insulating film 114 and the insulating film 116 is shown by a broken line. In the embodiment, the two-layer structure of the insulating film 114 and the insulating film 116 has been described. However, the present invention is not limited to this, and examples thereof include a single layer structure of the insulating film 114, a single layer structure of the insulating film 116, and a three-layer structure. A laminated structure of more than one layer may also be used.

[0071] Note that the source electrode 112a, the drain electrode 112b, and the first oxide semiconductor film 110 An insulating film 122 may be provided between the insulating film 122 and the insulating film a. An example of this case is shown in FIGS. 17(A) and 17(B). The source electrode 112a, the drain electrode 112b, the first oxide semiconductor film 110a, and are connected via contact holes provided in the insulating film 122. The insulating film 108 may be made of the same material or film quality as that described above for the insulating film 108.

[0072] <Method for manufacturing a display device> Next, an example of a method for manufacturing the semiconductor device shown in FIGS. 1A and 1B will be described with reference to FIGS. 2 and 3. This will be explained using:

[0073] First, a gate electrode including a second oxide semiconductor film 104a and a pair of electrodes A second oxide semiconductor film 104b serving as one of the electrodes is formed on the substrate 1. 102 and the second oxide semiconductor films 104a and 104b, and insulating films 106 and 107 are formed on the second oxide semiconductor films 104a and 104b. The velum 108 is formed (see FIG. 2(A)).

[0074] The substrate 102, the second oxide semiconductor films 104a and 104b, and the insulating films 106 and 1 The material 07 can be selected from the materials listed above. In this embodiment, a glass substrate is used as the substrate 102, and the second oxide semiconductor film 104a 104b is an In-Ga-Zn oxide film (metallic film of In:Ga:Zn=1:1:1). An oxide target is used. The insulating film 106 is made of a material capable of releasing hydrogen. The insulating film 107 is a silicon nitride film capable of releasing oxygen. A silicon film is used.

[0075] Silicon nitride capable of releasing hydrogen is added to the second oxide semiconductor films 104a and 104b. By providing the films in contact with each other, the resistivity of the second oxide semiconductor films 104a and 104b can be reduced. This makes it possible to

[0076] The second oxide semiconductor films 104a and 104b are formed by depositing oxide semiconductor films on the substrate 102. After the film formation, the oxide semiconductor film is patterned so that a desired region of the oxide semiconductor film remains, and then an unnecessary region is removed. It is formed by etching.

[0077] Next, a second oxide semiconductor film 104a is formed on the insulating film 108 at a position overlapping with the gate electrode including the second oxide semiconductor film 104a. The first oxide semiconductor film 110a is disposed on the insulating film 108, and the second oxide semiconductor film 104b is disposed on the insulating film 108. and the first oxide semiconductor film 110b are formed so as to overlap with each other (see FIG. 2B). (see).

[0078] The first oxide semiconductor films 110a and 110b are made of a material selected from the materials listed above. In this embodiment, the first oxide semiconductor film 110a 110b is an In-Ga-Zn oxide film (metallic film of In:Ga:Zn=1:1:1). An oxide target is used.

[0079] The first oxide semiconductor films 110a and 110b are formed on the insulating film 108. After forming the oxide semiconductor film, the oxide semiconductor film is patterned so that a desired region remains, and then an unnecessary region is removed. The area is formed by etching.

[0080] The first oxide semiconductor film 110a and the first oxide semiconductor film 110b are made of the same oxide. Since they are formed by processing a nitride semiconductor film, they contain at least the same metal element. During etching of the first oxide semiconductor films 110a and 110b, over-etching As a result, a part of the insulating film 107 (the area exposed from the first oxide semiconductor films 110a and 110b) is The film thickness may decrease due to etching of the film.

[0081] After the first oxide semiconductor films 110a and 110b are formed, heat treatment is preferably performed. The treatment is carried out at a temperature of 250°C or higher and 650°C or lower, preferably 300°C or higher and 500°C or lower, more preferably is at a temperature of 350℃ to 450℃, in an inert gas atmosphere, and with oxidizing gas at 10 ppm or more. The heat treatment may be carried out in an atmosphere containing an inert gas or a reduced pressure atmosphere. After the heat treatment in the atmosphere, oxygen released from the first oxide semiconductor films 110a and 110b was removed. To compensate for this, the heat treatment may be carried out in an atmosphere containing 10 ppm or more of oxidizing gas. Therefore, at least the insulating films 106 and 107 and the first oxide semiconductor films 110a and 110b Furthermore, impurities such as hydrogen and water can be removed from the first oxide. This may be done before processing the nitride semiconductor films 110a and 110b into islands.

[0082] Note that the transistor 150 having the first oxide semiconductor film 110a as a channel region is stably In order to provide the desired electrical characteristics, impurities in the first oxide semiconductor film 110a are reduced, and It is effective to make the first oxide semiconductor film 110a intrinsic or substantially intrinsic.

[0083] Next, a conductive film is formed over the insulating film 108 and the first oxide semiconductor films 110a and 110b. The conductive film is then patterned so that desired regions remain, and then unnecessary regions are etched away. As a result, the source electrode 112a and the source electrode 112b are formed on the insulating film 108 and the first oxide semiconductor film 110a. A drain electrode 112b is formed (see FIG. 2C).

[0084] The source electrode 112a and the drain electrode 112b are made of the above-listed materials. In this embodiment, the source electrode 112a and The drain electrode 112b is made of a three-layer structure consisting of a titanium film, an aluminum film, and another titanium film. A laminated structure is used.

[0085] Next, the insulating film 108, the first oxide semiconductor films 110a and 110b, and the source electrode 112a Insulating films 114 and 116 are formed over the gate electrode 112b and the drain electrode 112b (see FIG. 2D).

[0086] The insulating films 114 and 116 can be formed by selecting from the materials listed above. In this embodiment, the insulating films 114 and 116 are made of a material that can release oxygen. A silicon oxynitride film that can be used is used.

[0087] Next, the insulating films 114 and 116 are patterned so that desired regions remain, and then unnecessary regions are removed. An opening 140 is formed by etching the area (see FIG. 3(A)).

[0088] The opening 140 is formed so as to expose the first oxide semiconductor film 110b. The method for forming 140 can be, for example, dry etching. The method for forming the opening 140 is not limited to this, and may be a wet etching method or a dry etching method. The formation method may be a combination of dry etching and wet etching. The etching process for forming the opening 140 exposes the first oxide semiconductor film 110b. The film thickness may decrease.

[0089] After this, it is preferable to perform a heat treatment. A part of the oxygen contained in the film 116 is transferred to the first oxide semiconductor film 110a, and the first oxide semiconductor film 110a is formed. As a result, the oxygen vacancies in the first oxide semiconductor film 110a can be compensated for. The amount of oxygen vacancies in the semiconductor film 110a can be reduced. The amount of oxygen vacancies in the first oxide semiconductor film 110b that is not in contact with the first oxide semiconductor film 110b is not reduced. The semiconductor film 110b contains more oxygen vacancies than the first oxide semiconductor film 110a. The heat treatment conditions are the same as those for the heat treatment after the formation of the first oxide semiconductor films 110a and 110b. The process can be the same as above.

[0090] Next, the insulating film 116 and the first oxide semiconductor film 110b are formed on the insulating film 116 so as to cover the opening 140. An insulating film 118 is formed on the insulating film 118 (see FIG. 3B).

[0091] The insulating film 118 can be formed by selecting a material from the materials listed above. In this embodiment, the insulating film 118 is made of silicon nitride capable of releasing hydrogen. The silicon film is used. Hydrogen contained in the insulating film 118 diffuses into the first oxide semiconductor film 110b. As a result, the resistivity of the first oxide semiconductor film 110b decreases. As the resistivity of the film 110b decreases, the first oxide semiconductor film 110b shown in FIGS. 3(A) and 3(B) The hatching of 110b is changed.

[0092] The resistivity of the first oxide semiconductor film 110b is at least equal to that of the first oxide semiconductor film 110a. lower than 1 x 10-3 Ωcm or more 1×10 4 Less than Ωcm, more preferred 1×10 -3 Ωcm or more 1×10 -1 It is preferable that the resistivity of the insulating film 11 is less than Ωcm. 8 is a diagram showing the structure of the transistor when external impurities such as water, alkali metals, alkaline earth metals, etc. This also has the effect of preventing diffusion into the first oxide semiconductor film 110a included in the sta 150.

[0093] In addition, the silicon nitride film used as the insulating film 118 in this embodiment is a blocking film. To enhance the thermal conductivity, it is preferable to form the film at a high temperature, for example, 100° C. or higher than the distortion point of the substrate. It is preferable to form the film by heating at a temperature of 300°C or higher and 400°C or lower. .

[0094] In addition, the capacitor 160 is formed along with the formation of the first oxide semiconductor film 110b. The capacitor 160 has a structure in which a dielectric layer is sandwiched between a pair of electrodes, and one of the pair of electrodes is The other of the pair of electrodes is the second oxide semiconductor film 104b, and the other of the pair of electrodes is the first oxide semiconductor film 110. The insulating film 108 functions as a dielectric layer of the capacitor element 160.

[0095] Through the above steps, the transistor 150 and the capacitor 160 are formed on the same substrate. It is possible.

[0096] As described above, the structures, methods, etc. described in this embodiment may be different from the structures, methods, etc. described in other embodiments. They can be used in appropriate combinations.

[0097] (Embodiment 2) In this embodiment, a semiconductor device according to one embodiment of the present invention is described. The modified example of the device will be described with reference to Figs. 4 to 6. The same reference numerals as those in FIG. 3 are used for parts that are the same as those in FIG. 3 or have the same functions. Therefore, the repeated explanation will be omitted.

[0098] <Configuration Example of Semiconductor Device (Modification 1)> FIG. 4A is a top view of a semiconductor device of one embodiment of the present invention, and FIG. 4B is a top view of a semiconductor device of FIG. ) corresponds to a cross-sectional view of the cut surface between the dashed dotted lines EF and GH. In FIG. 4(A), in order to avoid complication, only some of the components of the semiconductor device (gate) are shown. The illustration omits the gate insulating film, etc.

[0099] The semiconductor device shown in FIGS. 4A and 4B includes a first oxide semiconductor film 110a and a second oxide semiconductor film 110b. A transistor 151 including a compound semiconductor film 104a and a capacitor including an insulating film between a pair of electrodes. In the capacitor 161, one of a pair of electrodes is a second oxide. a first oxide semiconductor film 104b on the same plane as the oxide semiconductor film 104a; The other is a conductive film 120 .

[0100] The transistor 151 has a gate electrode including a second oxide semiconductor film 104a over a substrate 102. and a gate insulating film on the gate electrode including the second oxide semiconductor film 104a. The insulating film 108 and the gate electrode including the second oxide semiconductor film 104a on the insulating film 108 overlap each other. The first oxide semiconductor film 110a at the position where the first oxide semiconductor film 110a is to be folded and the source on the first oxide semiconductor film 110a are The source electrode 112a and the drain electrode 112b are shown in FIGS. The transistor 151 has a so-called bottom gate structure.

[0101] In addition, the first oxide semiconductor film 110a and the source Insulating films 114, 116, and 118 are formed on the electrode 112a and the drain electrode 112b. The insulating films 114, 116, and 118 function as protective insulating films for the transistor 151. The insulating films 114, 116, and 118 have openings that reach the drain electrode 112b. An opening 142 is formed, and a conductive film 120 is formed on the insulating film 118 so as to cover the opening 142. The conductive film 120 functions as, for example, a pixel electrode.

[0102] The capacitor 161 is a second capacitor having a function as one of a pair of electrodes on the substrate 102. and a dielectric film on the first oxide semiconductor film 104b. and insulating films 108, 114, 116, and 118. The other electrode of the pair of electrodes overlaps with the second oxide semiconductor film 104b with an intervening The conductive film 120 has a function as a pixel electrode. The capacitor has a function as an electrode of a capacitor element.

[0103] As described above, the insulating film 108 serves as a gate insulating film in the transistor 151. In the capacitive element 161, it functions as a part of the dielectric film. 114, 116, and 118 function as protective insulating films in the transistor 151, In the capacitance element 161, it functions as a part of the dielectric film. In the present invention, the insulating films 114, 116, and 118 are provided as part of the dielectric film. However, the present invention is not limited to this example. For example, in the manufacturing process of the transistor 151, When the opening 142 is formed, the insulating films 114, 116, and 118 of the capacitor element 161 may be removed. .

[0104] The capacitor 161 has a light-transmitting property. The oxide semiconductor film 104b, the insulating films 108, 114, 116, and 118, and the conductive film 120 In this way, the capacitive element 161 is made of a light-transmitting material. By having this property, it is possible to widely (large area) Therefore, a semiconductor device having an increased aperture ratio and an increased capacitance can be obtained. As a result, a semiconductor device with excellent display quality can be obtained. The element 161 can be manufactured by utilizing the manufacturing process of the transistor 151. Therefore, a semiconductor device can be obtained at low manufacturing costs.

[0105] Note that the insulating films 106 and 118 contain at least hydrogen. The insulating films 107, 114, and 116 are made of insulating films containing at least oxygen. As shown in FIG. 1, the insulating film used for the transistor 151 and the capacitor 161 or the insulating film used for the transistor 151 By using the insulating film in contact with the capacitor element 161 as the insulating film having the above-described structure, The first oxide semiconductor film and the second oxide semiconductor film included in the resistor 151 and the capacitor 161 The resistivity of the film can be controlled.

[0106] Note that the first oxide semiconductor film 110a and the second oxide semiconductor films 104a and 104b The resistivity can be controlled by taking into consideration the description of the first embodiment.

[0107] The semiconductor device shown in FIGS. 1A and 1B of the first embodiment and the semiconductor device shown in FIGS. The main difference between the semiconductor devices is that the other electrode of the capacitor element 161 is a conductive film 120. In this way, the other of the pair of electrodes of the capacitor 161 is a conductive film that functions as a pixel electrode. It may also be a membrane 120 .

[0108] As described above, in the semiconductor device according to one embodiment of the present invention, In other words, a conductive film that functions as an electrode of a capacitor element and a conductive film that functions as an electrode of a capacitor element are simultaneously formed. a conductive film serving as a gate electrode of a transistor and a conductive film serving as an electrode of a capacitor element; By forming the conductive film on the same surface, it is possible to reduce manufacturing costs. A conductive film that functions as a gate electrode of a transistor and a conductive film that functions as an electrode of a capacitor element The film includes an oxide semiconductor film. By performing appropriate treatment on the oxide semiconductor film, A conductive film having high conductivity and light-transmitting properties can be obtained. The transistor and / or the capacitor can be made light-transmitting.

[0109] Note that the source electrode 112a, the drain electrode 112b, and the first oxide semiconductor film 110 An insulating film 122 may be provided between the insulating film 122 and the insulating film a. An example of this case is shown in FIGS. 18(A) and 18(B). vinegar.

[0110] The conductive film 120 is formed at the same time and etched at the same time. 20a may be provided so as to overlap with the channel region of the transistor. 15(A) and 19(A). The conductive film 120a is, for example, the same as the conductive film 120. Since they are deposited and etched at the same time and formed at the same time, they have the same material. Therefore, it is possible to suppress an increase in the number of process steps. The conductive film 120a may be formed in a different process from that of the conductive film 120. The conductive film 120a has a region overlapping with the channel region of the transistor. Therefore, the conductive film 120a functions as a second gate electrode of the transistor. Therefore, the conductive film 120a may be connected to the second oxide semiconductor film 104a. Alternatively, the conductive film 120a is not connected to the second oxide semiconductor film 104a and is connected to the second oxide semiconductor film 104b. A signal or a potential different from that supplied to the compound semiconductor film 104a may be supplied to the compound semiconductor film 104b.

[0111] Here, the details of other components of the semiconductor device shown in FIGS. 4(A) and 4(B) are as follows: The explanation is given below.

[0112] <Conductive film> The conductive film 120 functions as a pixel electrode. A material that is transparent to visible light may be used. Specifically, indium (In), It is recommended to use a material containing one of zinc (Zn) and tin (Sn). The film 120 may be, for example, an indium oxide film containing tungsten oxide, a tungsten oxide film, or the like. Indium zinc oxide containing titanium oxide, Indium oxide containing titanium oxide Indium Tin Oxide, Indium Tin Oxide (ITO), Indium Zinc Oxide, Silicon Oxide A conductive material having light-transmitting properties, such as indium tin oxide doped with silicon, can be used. The conductive film 120 can be formed by, for example, a sputtering method. do.

[0113] <Method for manufacturing a display device (variation 1)> Next, an example of a method for manufacturing the semiconductor device shown in FIGS. 4A and 4B will be described with reference to FIGS. 5 and 6. This will be explained using:

[0114] First, a gate electrode including a second oxide semiconductor film 104a and a pair of electrodes A second oxide semiconductor film 104b serving as one of the electrodes is formed. An insulating film 108 including insulating films 106 and 107 is formed on the oxide semiconductor films 104a and 104b. (See Figure 5(A)).

[0115] Next, a second oxide semiconductor film 104a is formed on the insulating film 108 at a position overlapping with the gate electrode including the second oxide semiconductor film 104a. A first oxide semiconductor film 110a is formed in this position (see FIG. 5B).

[0116] The first oxide semiconductor film 110a is formed by depositing an oxide semiconductor film on the insulating film 108. The semiconductor film is patterned so that the desired region remains, and then the unnecessary region is etched away. It is formed by

[0117] In addition, when etching the first oxide semiconductor film 110a, over-etching may occur. Therefore, a part of the insulating film 107 (a region exposed from the first oxide semiconductor film 110a) is etched. This may result in a decrease in the film thickness.

[0118] After the first oxide semiconductor film 110a is formed, heat treatment is preferably performed. This can be performed by taking into consideration the heat treatment performed after the formation of the first oxide semiconductor film 110a in the first embodiment. Cut.

[0119] Next, a conductive film is formed over the insulating film 108 and the first oxide semiconductor film 110a. The film is patterned to leave the desired areas, and then the unwanted areas are etched away. A source electrode 112a and a drain electrode 112b are formed on the first oxide semiconductor film 110a. (See Figure 5(C)).

[0120] Next, the insulating film 108, the first oxide semiconductor film 110a, the source electrode 112a, and the drain electrode 112b are formed. Insulating films 114, 116, and 118 are formed on the inner electrode 112b (see FIG. 5(D)).

[0121] Next, the insulating films 114, 116, and 118 are patterned so that desired regions remain. After that, the unnecessary region is etched to form an opening 142 (see FIG. 6(A)).

[0122] The opening 142 is formed so as to expose the drain electrode 112b. As a method for forming the openings, for example, a dry etching method can be used. The method for forming 42 is not limited to this, and may be a wet etching method or a dry etching method. A combination of the chipping method and the wet etching method may also be used.

[0123] Next, a conductive film is formed on the insulating film 118 so as to cover the opening 142, and a desired region of the conductive film is The conductive film 120 is formed by patterning and etching so that a region remains (FIG. 6(B)). )reference).

[0124] Through the above steps, the transistor 151 and the capacitor 161 are formed over the same substrate. It is possible.

[0125] An insulating film 118a may be disposed on the insulating film 118. An example of this case is shown in FIG. 19B and 19C. The insulating film 118a may be, for example, The insulating film 118a can be formed using an organic resin material. Examples of the resin include acrylic resins, polyimide resins, and polyamide resins.

[0126] As shown in FIG. 15(C) and FIG. 19(C), a conductive film 121 may be provided. The conductive film 121 may be provided so as to overlap with the channel region of the transistor. The conductive film 121 may be formed using the same material as that described for the conductive film 120. The conductive film 121 has a region overlapping with the channel region of the transistor. The conductive film 121 functions as a second gate electrode of the transistor. The conductive film 121 may be connected to the second oxide semiconductor film 104a. The first oxide semiconductor film 104a is not connected to the second oxide semiconductor film 104a and has a different signal from the first oxide semiconductor film 104a. A different signal or potential may be supplied.

[0127] The conductive film 121 is formed at the same time as the conductive film 122 and etched at the same time. The capacitor element may be configured by providing 21a so as to overlap with the electrode of the capacitor element. Examples are shown in Figures 20(A), (B), and (C). As a result, the capacitance value of the capacitive element can be increased. This can be done.

[0128] As described above, the structures, methods, etc. described in this embodiment may be different from the structures, methods, etc. described in other embodiments. They can be used in appropriate combinations.

[0129] (Embodiment 3) In this embodiment, a semiconductor device according to one embodiment of the present invention is described. A modified example of the device will be described with reference to FIG. 7. The same symbols are used for parts that are the same as the symbols used above or parts that have the same functions. Repetitive explanation will be omitted.

[0130] <Configuration Example of Semiconductor Device (Modification 2)> 7A is a top view of a semiconductor device of one embodiment of the present invention, and FIG. 7B is a top view of a semiconductor device of FIG. ) corresponds to the cross-sectional view of the cut surface between the dashed dotted lines IJ and KL. In FIG. 7(A), in order to avoid complication, only some of the components of the semiconductor device (gate) are shown. The illustration omits the gate insulating film, etc.

[0131] The semiconductor device shown in FIGS. 7A and 7B includes a first oxide semiconductor film 110a and a second oxide semiconductor film 110b. a transistor 152 including a compound semiconductor film 104a, and a capacitor including an insulating film between a pair of electrodes; element 162.

[0132] The transistor 152 has a gate electrode including a second oxide semiconductor film 104a on the substrate 102. and a gate insulating film on the gate electrode including the second oxide semiconductor film 104a. The insulating film 108 and the gate electrode including the second oxide semiconductor film 104a on the insulating film 108 overlap each other. The first oxide semiconductor film 110a at the position where the first oxide semiconductor film 110a is to be folded and the source on the first oxide semiconductor film 110a are The source electrode 112a and the drain electrode 112b are shown in FIGS. The transistor 152 has a so-called bottom gate structure.

[0133] In addition, the first oxide semiconductor film 110a and the source Insulating films 114, 116, and 118 are formed on the electrode 112a and the drain electrode 112b. The insulating films 114, 116, and 118 function as protective insulating films for the transistor 152. The insulating films 114, 116, and 118 have openings that reach the drain electrode 112b. An opening 142 is formed, and a conductive film 120 is formed on the insulating film 118 so as to cover the opening 142. The conductive film 120 functions as, for example, a pixel electrode.

[0134] In the capacitor 162, one of a pair of electrodes is formed of the second oxide semiconductor film 104b. The other of the pair of electrodes is a conductive film 120. The capacitor 162 is The first oxide semiconductor film 110a further includes an electrode. The electrode is formed on the same plane as the first oxide semiconductor film 110a. The resulting first oxide semiconductor film 110b.

[0135] In this way, by providing an additional electrode between the pair of electrodes, the area of ​​the capacitor element can be reduced. The capacitance can be increased without increasing the capacitance. The capacitor 162 has a structure in which the second oxide semiconductor film 104b and the first oxide semiconductor film 104b are connected to each other. a first capacitance element having an insulating film 108 sandwiched between oxide semiconductor films 110a as a dielectric film; The insulating film 118 sandwiched between the first oxide semiconductor film 110a and the conductive film 120 is a dielectric film. The second capacitance element is stacked on the first capacitance element.

[0136] As described above, the insulating film 108 is used as a gate insulating film in the transistor 152. In the capacitance element 162, it functions as a part of the dielectric film. 4, 116, and 118 function as a protective insulating film in the transistor 152. The insulating film 118 functions as a part of the dielectric film in the capacitive element 162 .

[0137] The capacitor 162 has a light-transmitting property. the first oxide semiconductor film 110b, the second oxide semiconductor film 104b, the insulating films 108 and 118, and The capacitive element and the conductive film 120 are each made of a light-transmitting material. Since the electrode 162 is light-transmitting, the electrode 162 is transparent to light in an area other than the area where the transistor is formed in the pixel. Since it can be formed large (in a large area), it is possible to increase the aperture ratio and the capacitance value. As a result, a semiconductor device with excellent display quality can be obtained. The capacitor 162 can be manufactured by utilizing the manufacturing process of the transistor 152. Therefore, a semiconductor device can be obtained at low manufacturing costs.

[0138] Note that the insulating films 106 and 118 contain at least hydrogen. The insulating films 107, 114, and 116 are made of insulating films containing at least oxygen. As shown in FIG. 1, the insulating film used for the transistor 152 and the capacitor 162 or the insulating film used for the transistor 152 By using the insulating film having the above-described structure as the insulating film in contact with the capacitor element 162, The first oxide semiconductor film and the second oxide semiconductor film included in the resistor 152 and the capacitor 162 The resistivity of the film can be controlled.

[0139] The first oxide semiconductor films 110a and 110b and the second oxide semiconductor film 104a The resistivity of 104b can be controlled by taking into consideration the description of the first embodiment. Cut.

[0140] The semiconductor device shown in FIGS. 1A and 1B of the first embodiment and the semiconductor device shown in FIGS. The main difference between the semiconductor devices is the electrode structure of the capacitor element 162.

[0141] In the semiconductor device of one embodiment of the present invention, a conductive film that functions as a gate electrode of a transistor In other words, a conductive film that functions as an electrode of a transistor is formed at the same time. The conductive film that functions as the gate electrode of the capacitor and the conductive film that functions as the electrode of the capacitor are formed in the same By forming the transistor on the surface, it is possible to reduce the manufacturing cost. The conductive film serving as the gate electrode of the capacitor element and the conductive film serving as the electrode of the capacitor element are made of an oxide. The oxide semiconductor film has a high conductivity when subjected to appropriate treatment. The conductive film can be a light-transmitting conductive film. The capacitor and / or the capacitor element can be made light-transmitting.

[0142] The semiconductor device shown in FIGS. 7A and 7B can be manufactured by the same method as in FIGS. 4A and 4B. This allows it to be formed.

[0143] As in FIG. 15(A), the conductive film 120a is formed so as to overlap the channel region of the transistor. Examples of this case are shown in Figures 16(A) and 19(A).

[0144] 15(B) and (C), an insulating film 118a is disposed on the insulating film 118. An example of this case is shown in Figures 16(B) and 16(C) and Figures 19(B) and 19(C).

[0145] As described above, the structures, methods, etc. described in this embodiment may be different from the structures, methods, etc. described in other embodiments. They can be used in appropriate combinations.

[0146] (Fourth embodiment) In this embodiment, a semiconductor device according to one embodiment of the present invention is described. Modified examples of the device will be described with reference to Figs. 8 to 10. The same reference numerals are used to designate parts that are the same as those shown in Figure 3 or parts that have the same functions. The repeated explanation will be omitted.

[0147] <Configuration Example of Semiconductor Device (Modification 3)> FIG. 8A is a top view of a semiconductor device of one embodiment of the present invention, and FIG. 8B is a top view of a semiconductor device of one embodiment of the present invention. ) corresponds to a cross-sectional view of the cut surface between the dashed dotted line MN and the dashed dotted line OP. In FIG. 8(A), in order to avoid complication, only some of the components of the semiconductor device (gate) are shown. The illustration omits the gate insulating film, etc.

[0148] The semiconductor device shown in FIGS. 8A and 8B includes a first oxide semiconductor film 210 and a second oxide semiconductor film 211. A transistor 250 including a compound semiconductor film 204a and a capacitor element including an insulating film between a pair of electrodes. In the capacitor 260, one of the pair of electrodes is a second oxide. The second oxide semiconductor film 204b is on the same plane as the oxide semiconductor film 204a. The other is the conductive film 220 .

[0149] The transistor 250 includes an insulating film 216 on the substrate 202 and a first oxide film on the insulating film 216. a first oxide semiconductor film 210, a source electrode 212a and a drain electrode 212b on the first oxide semiconductor film 210; The electrode 212b and the insulating film 212 functioning as a gate insulating film on the first oxide semiconductor film 210 are 08 and the second oxide semiconductor film 210 on the insulating film 208 at a position overlapping with the first oxide semiconductor film 210. and a gate electrode including a conductive film 204a. The resistor 250 has a so-called top gate structure.

[0150] In addition, the transistor 250, more specifically, the gate electrode including the second oxide semiconductor film 204a Insulating films 218 and 217 are formed on the gate electrode, the source electrode 212a, and the drain electrode 212b. The insulating films 218 and 217 function as protective insulating films for the transistor 250. In addition, the insulating films 218 and 217 have an opening 240 that reaches the drain electrode 212b. A conductive film 220 is formed on the insulating film 217 so as to cover the opening 240. The conductive film 220 functions as, for example, a pixel electrode.

[0151] The capacitance element 260 is formed by an insulating film 216 on the substrate 202 and an insulating film 208 on the insulating film 216. a second oxide semiconductor film 204 over the insulating film 208, which functions as one of a pair of electrodes; b, and insulating films 218 and 217 functioning as dielectric films on the second oxide semiconductor film 204b. and a pair of insulating films 218 and 217 positioned to overlap with the second oxide semiconductor film 204b. and a conductive film 220 that functions as the other electrode of the first electrode. has a function as a pixel electrode and a function as an electrode of a capacitor element.

[0152] As described above, the insulating film 208 serves as a gate insulating film in the transistor 250. In the capacitive element 260, it functions as a part of the dielectric film. 218 and 217 function as a protective insulating film in the transistor 250 and as a capacitor element. In 260, it functions as a part of the dielectric film. In the above example, the insulating films 218 and 217 are provided as part of the dielectric film. For example, in the manufacturing process of the transistor 250, The insulating films 218 and 217 may be partially removed.

[0153] In addition, the capacitor 260 has a light-transmitting property. The films 216, 206, 207, 218, and 217 are each made of a light-transmitting material. In this way, when the capacitor 260 has light-transmitting properties, the transistor in the pixel It can be formed in a large area (large area) in areas other than the area where it is to be formed, which increases the aperture ratio. As a result, a semiconductor device having an improved display quality can be obtained. A semiconductor device can be obtained. Therefore, a semiconductor device can be obtained at low manufacturing cost. It is possible.

[0154] Note that insulating films containing at least hydrogen are used as the insulating films 207 and 218. The insulating films 216, 206, and 217 are made of insulating films containing at least oxygen. As shown in FIG. 1, the insulating film used for the transistor 250 and the capacitor 260 or the insulating film used for the transistor 250 By using the insulating film in contact with the capacitor element 260 as the insulating film having the above-described structure, The first oxide semiconductor film and the second oxide semiconductor film included in the transistor 250 and the capacitor 260 The resistivity of the film can be controlled.

[0155] Specifically, in the transistor 250, the first oxide semiconductor film 210 Since the second oxide semiconductor film 204a and the second oxide semiconductor film 204b are used as a formation region, the resistivity of the second oxide semiconductor film 204a is higher than that of the second oxide semiconductor film 204b. On the other hand, the second oxide semiconductor films 204a and 204b function as electrodes. Therefore, the resistivity is low.

[0156] Here, the first oxide semiconductor film 210 and the second oxide semiconductor films 204a and 204b The method for controlling the resistivity will be explained below.

[0157] <Method 2 for controlling the resistivity of oxide semiconductors> The first oxide semiconductor film 210 and the second oxide semiconductor films 204a and 204b are formed using The oxide semiconductor that can be formed has oxygen vacancies in the film and / or impurity concentrations such as hydrogen and water in the film. Therefore, the first oxide semiconductor The conductive film 210 and the second oxide semiconductor films 204a and 204b are oxygen deficient and / or impurities are generated. Select a treatment that increases the concentration of oxygen vacancies and / or impurities, or a treatment that reduces the concentration of oxygen vacancies and / or impurities. This makes it possible to control the resistivity of each oxide semiconductor.

[0158] Specifically, the second oxide semiconductor film 2 04a, an oxide semiconductor film used for the second oxide semiconductor film 204b which functions as an electrode of the capacitor 260, a plasma treatment on the oxide semiconductor film to increase oxygen vacancies in the oxide semiconductor film; and and / or by increasing impurities such as hydrogen and water in the oxide semiconductor film. In addition, the oxide semiconductor can have a high rear density and low resistance. and forming an insulating film containing hydrogen in contact with the oxide semiconductor, and diffusing hydrogen from the insulating film containing hydrogen into the oxide semiconductor. This makes it possible to provide an oxide semiconductor having high carrier density and low resistivity.

[0159] On the other hand, the first oxide semiconductor film 2 which functions as a channel formation region of the transistor 250 10 is provided with the insulating films 216 and 206 so that it does not come into contact with the insulating film 218 containing hydrogen. In addition, at least one of the insulating films 216 and 206 is capable of releasing oxygen. By using an insulating film that can be formed as the first oxide semiconductor film 210, oxygen can be supplied to the first oxide semiconductor film 210. The oxygen vacancies in the first oxide semiconductor film 210 or at the interface are filled with oxygen. The insulating film capable of releasing oxygen is, for example, For example, a silicon oxide film or a silicon oxynitride film can be used.

[0160] As described above, in the semiconductor device according to one embodiment of the present invention, In other words, a conductive film that functions as an electrode of a capacitor element and a conductive film that functions as an electrode of a capacitor element are simultaneously formed. a conductive film serving as a gate electrode of a transistor and a conductive film serving as an electrode of a capacitor element; By forming the conductive film on the same surface, it is possible to reduce manufacturing costs. A conductive film that functions as a gate electrode of a transistor and a conductive film that functions as an electrode of a capacitor element The film includes an oxide semiconductor film. By performing appropriate treatment on the oxide semiconductor film, A conductive film having high conductivity and light-transmitting properties can be obtained. The transistor and / or the capacitor can be made light-transmitting.

[0161] Here, the details of other components of the semiconductor device shown in FIGS. 8(A) and 8(B) are as follows: The explanation is given below.

[0162] <Insulating film> The insulating film 216 can be made of the materials listed for the insulating film 116 in the first embodiment. The insulating films 206 and 207 can be formed by the same method as in the first embodiment. The insulating films 106 and 107 can be formed using the materials listed above.

[0163] <First Oxide Semiconductor Film and Second Oxide Semiconductor Film> The first oxide semiconductor film 210 may be the first oxide semiconductor film 110a of the first embodiment. The second oxide semiconductor film 2 can be formed by using the materials listed in . The second oxide semiconductor films 104a and 104b in Embodiment 1 are used as the oxide semiconductor films 104a and 104b. It can be formed by using the materials listed above.

[0164] <Source and drain electrodes> The source electrode 212a and the drain electrode 212b are the same as those of the source electrode 1 in the first embodiment. The drain electrode 112a and the drain electrode 112b can be formed by using the materials listed above. .

[0165] <Conductive film> The conductive film 220 can be made of the materials listed for the conductive film 120 in the second embodiment. It can be formed.

[0166] <Method for manufacturing a display device (modification 2)> Next, an example of a method for manufacturing the semiconductor device shown in FIGS. 8A and 8B will be described with reference to FIGS. 9 and 1. Explain using 0.

[0167] First, an insulating film 216 is formed on a substrate 202, and an oxide semiconductor film is formed on the insulating film 216. Thereafter, the oxide semiconductor film is patterned so that a desired region remains, and then unnecessary regions are removed. The oxide semiconductor film 210 is formed by etching the oxide semiconductor film 210 (see FIG. 9A). ).

[0168] Next, a conductive film is formed over the insulating film 216 and the first oxide semiconductor film 210. The desired area is patterned to remain, and then the unnecessary area is etched away to remove the A source electrode 212a and a drain electrode 212b are formed (see FIG. 9(B)).

[0169] Next, the insulating film 216, the first oxide semiconductor film 210, the source electrode 212a, and the drain electrode 212b are formed. An insulating film 208 including insulating films 206 and 207 and a second oxide semiconductor film A film 204 is formed (see FIG. 9(C)).

[0170] Next, a resist mask is formed over the second oxide semiconductor film 204. The film 204 is patterned to leave desired areas and then etched away unwanted areas. In this way, second oxide semiconductor films 204a and 204b are formed. The insulating films 206 and 207 below the conductive films 204a and 204b are also etched at the same time, and separated into islands. The insulating films 206 and 207 are separated from each other (see FIG. 9(D)).

[0171] Next, the insulating film 216, the source electrode 212a, the drain electrode 212b, and the second oxide Insulating films 218 and 217 are formed on the semiconductor films 204a and 204b (see FIG. 10(A)). .

[0172] Next, a resist mask is formed on the insulating film 217, and desired regions of the insulating films 218 and 217 are The opening 240 is then formed by patterning the silicon substrate so that the unnecessary area remains. The opening 240 is formed so as to reach the drain electrode 212b ( See Figure 10(B)).

[0173] Next, a conductive film is formed on the insulating film 217 so as to cover the opening 240, and a resist is formed on the conductive film. A mask is formed and patterned so that desired areas of the conductive film remain, and then unnecessary areas are removed. The conductive film 220 is formed by etching (see FIG. 10C).

[0174] Through the above steps, the transistor 250 and the capacitor 260 are formed on the same substrate. It is possible.

[0175] As described above, the structures, methods, etc. described in this embodiment may be different from the structures, methods, etc. described in other embodiments. They can be used in appropriate combinations.

[0176] (Embodiment 5) In this embodiment, a semiconductor device according to one embodiment of the present invention is described. A modified example of the device will be described with reference to FIG.

[0177] <Configuration Example of Semiconductor Device (Modification 4)> The semiconductor device illustrated in FIG. 11A includes the transistor 150 and the capacitor 150 described in Embodiment 1. The first oxide semiconductor films 110a and 110b of the substrate 160 are formed by stacking oxide films 410a and 410b. Therefore, the other components are the transistor 150 and the capacitor 1 60, and a detailed description thereof will be omitted.

[0178] The oxide stacked films 410a and 410b will be described in detail below.

[0179] The oxide stacked films 410a and 410b are formed by stacking oxide semiconductor films 420a and 420b and an oxide film In the following description, the oxide semiconductor film 420 a and 420b are the oxide semiconductor film 420, and oxide films 422a and 422b are the oxide film 422. Each will be described and explained.

[0180] The oxide semiconductor film 420 and the oxide film 422 have at least one common constituent element. Alternatively, the oxide semiconductor film 420 and the oxide film 42 The constituent elements of the two may be the same, but the compositions of the two may be different.

[0181] The oxide semiconductor film 420 is an In-M-Zn oxide (wherein M is Al, Ti, Ga, Y, Zr, or L a, Ce, Nd, Sn or Hf) to form an In-M-Zn oxide film. The atomic ratio of the metal elements in the sputtering target used in the present invention satisfies In≧M, Zn≧M. The atomic ratio of the metal elements in such a sputtering target is preferably: In:M:Zn=1:1:1, In:M:Zn=5:5:6(1:1:1.2), In: The atomic ratio of M:Zn to the oxide semiconductor film 420 to be formed is preferably 3:1:2. are the atomic ratios of the metal elements contained in the sputtering target as errors. This includes a fluctuation of plus or minus 20%.

[0182] When the oxide semiconductor film 420 is an In-M-Zn oxide, the sum of In and M is When the atomic percentage is 100 atomic %, the atomic ratio of In to M is preferably 25 atomic %. omic% or more, M is less than 75 atomic%, and more preferably In is 34 atomic% or more c% or more, and M is less than 66 atomic%.

[0183] The oxide semiconductor film 420 has an energy gap of 2 eV or more, preferably 2.5 eV or more. In this way, the oxide semiconductor having a wide energy gap is By using a conductor, the off-state current of a transistor can be reduced.

[0184] The thickness of the oxide semiconductor film 420 is 3 nm to 200 nm, preferably 3 nm to 100 nm. 00 nm or less, and more preferably 3 nm or more and 50 nm or less.

[0185] The oxide film 422 is typically made of In-Ga oxide, In-Zn oxide, or In-MnO. n oxides (M represents Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn or Hf) ) and the energy of the bottom of the conduction band is closer to the vacuum level than that of the oxide semiconductor film 420. Typically, the energy of the bottom of the conduction band of the oxide film 422 is The difference in energy from the bottom of the conduction band is 0.05 eV or more, 0.07 eV or more, or 0.1 eV or more, or 0.15 eV or more and 2 eV or less, 1 eV or less, 0.5 eV or less, or That is, the electron affinity of the oxide film 422 and the electron affinity of the oxide semiconductor film 420 are The difference from the electron affinity is 0.05 eV or more, 0.07 eV or more, 0.1 eV or more, or 0 0.15eV or more and 2eV or less, 1eV or less, 0.5eV or less, or 0.4eV or less is.

[0186] The oxide film 422 has the element M in a higher atomic ratio than In, and therefore has the following effects: (1) The energy gap of the oxide film 422 is increased. (2) (3) To reduce the electron affinity of the oxide film 422. (4) To block impurities from the outside. The insulating property is higher than that of the oxide semiconductor film 420. In addition, the element M has a low bonding strength with oxygen. Since M is a strong metallic element, having a higher atomic ratio than In makes it difficult for oxygen vacancies to occur. It becomes difficult.

[0187] When the oxide film 422 is an In-M-Zn oxide, the sum of In and M is 100 atom. When expressed as mic%, the atomic ratio of In to M is preferably 50 atomic % In. less than 50 atomic %; M is 50 atomic % or more; more preferably, In is less than 25 atomic % , M is 75 atomic % or more.

[0188] The oxide semiconductor film 420 and the oxide film 422 are made of In-M-Zn oxide (M is Al). , Ti, Ga, Y, Zr, La, Ce, Nd, Sn or Hf), oxide semi-conductor Compared with the conductor film 420, the atomic ratio of M contained in the oxide film 422 is large, and typically, , 1.5 times or more, preferably 2 times, the above atoms contained in the oxide semiconductor film 420. The atomic ratio is more preferably three times or more higher.

[0189] The oxide film 422 is made of In:M:Zn=x1:y1:z1 [atomic ratio], and is an oxide semiconductor. When the film 420 is In:M:Zn=x2:y2:z2 [atomic ratio], y1 / x1 is y 2 / x2, and preferably, y1 / x1 is 1.5 times or more greater than y2 / x2. More preferably, y1 / x1 is at least twice as large as y2 / x2, and even more preferably, y1 / x1 is three times or more larger than y2 / x2. When y2 is greater than or equal to x2, a transistor including an oxide semiconductor can have stable electrical characteristics. However, if y2 is three times or more of x2, it is difficult to obtain a Therefore, y2 should be less than three times x2. preferable.

[0190] When the oxide semiconductor film 420 and the oxide film 422 are an In-M-Zn oxide, The atomic ratio of the metal elements in the sputtering target used to form a Zn oxide film is: It is preferable that M>In and Zn≧M are satisfied. The atomic ratio of the group elements is In:Ga:Zn=1:3:2, In:Ga:Zn=1:3: 3, In:Ga:Zn=1:3:4, In:Ga:Zn=1:3:5, In:Ga:Zn =1:3:6, In:Ga:Zn=1:3:7, In:Ga:Zn=1:3:8, In: Ga:Zn=1:3:9, In:Ga:Zn=1:3:10, In:Ga:Zn=1:6 :4, In:Ga:Zn=1:6:5, In:Ga:Zn=1:6:6, In:Ga:Z n=1:6:7, In:Ga:Zn=1:6:8, In:Ga:Zn=1:6:9, In The preferred ratio is Ga:Zn=1:6:10. The atomic ratio of metal elements contained in the formed oxide semiconductor film 420 and oxide film 422 is The error is the planar ratio of the atomic number of the metal elements contained in the sputtering target. Includes fluctuations of ±20%.

[0191] However, the semiconductor characteristics and electrical characteristics (field effect) of the required transistors are not limited to these. It is sufficient to use an appropriate composition depending on the required properties (e.g., the mobility, threshold voltage, etc.). In order to obtain semiconductor characteristics of a transistor, the carrier density and impurity of the oxide semiconductor film 420 are controlled. The material concentration, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc. are set appropriately. It is preferable.

[0192] The oxide film 422 is formed by oxidation when forming the insulating film 114 or the insulating film 116 to be formed later. The oxide film 422 also functions as a film for mitigating damage to the oxide semiconductor film 420. The thickness is set to 100 nm or more, preferably 3 nm or more and 50 nm or less.

[0193] The oxide semiconductor film 420 contains silicon or carbon, which is one of Group 14 elements. As a result, oxygen vacancies increase in the oxide semiconductor film 420, causing the oxide semiconductor film 420 to become n-type. The concentration of silicon or carbon in the oxide semiconductor film 420, or the concentration of the oxide film 422 and the oxide semiconductor The concentration of silicon and carbon near the interface with the conductive film 420 (obtained by secondary ion mass spectrometry) concentration) is 2 x 10 18 atoms / cm 3 Less than or equal to 2 x 10 17 atoms / cm 3 The following applies.

[0194] In addition, in the oxide semiconductor film 420, alkali metal ions obtained by secondary ion mass spectrometry The concentration of metal or alkaline earth metal is 1×10 18 atoms / cm 3 The following is preferably is 2 x 10 16 atoms / cm 3 The alkali metals and alkaline earth metals are as follows: When bonded to an oxide semiconductor, carriers may be generated, increasing the off-state current of the transistor. Therefore, the alkali metal or alkali metal in the oxide semiconductor film 420 may be easily removed. It is preferable to reduce the concentration of alkali earth metals.

[0195] When nitrogen is contained in the oxide semiconductor film 420, electrons serving as carriers are generated, and As a result, the carrier density increases and it becomes easier to make the semiconductor n-type. Therefore, the transistor having the oxide semiconductor film 420 tends to be normally on. In this case, it is preferable that nitrogen is reduced as much as possible. For example, in secondary ion mass spectrometry, The nitrogen concentration obtained by the method is 5 x 10 18atoms / cm 3 It is preferable to do the following: stomach.

[0196] Note that the oxide semiconductor film 420 and the oxide film 422 are not simply stacked but are formed continuously. The structure in which the energy of the bottom of the conduction band changes continuously between the layers is called the "junction." That is, at the interface of each film, a transistor for the oxide semiconductor is formed. The stacking layer is free of impurities that form defect levels such as drop centers and recombination centers. Assume that impurities are present between the stacked oxide semiconductor film 420 and the oxide film 422. When they are mixed, the continuity of the energy bands is lost, carriers are trapped at the interface, Or they recombine and disappear.

[0197] To form continuous junctions, a multi-chamber deposition system equipped with a load lock chamber is required. Each film is laminated in succession using a sputtering device without being exposed to the atmosphere. Each chamber in the sputtering device is required for the oxide semiconductor film. In order to remove impurities such as water as much as possible, an adsorption type vacuum pump such as a cryopump is used. High vacuum pumping (5×10 -7 Pa~1×10 -4 It is preferable to Alternatively, a turbomolecular pump and cold trap can be combined to evacuate the chamber from the exhaust system. It is preferable to prevent gases, especially gases containing carbon or hydrogen, from flowing back into the .

[0198] Here, the band structure of the stacked oxide film will be described with reference to FIG.

[0199] FIG. 11(B) shows a part of the band structure of the laminated oxide film and the insulating film in contact with the laminated oxide film. Here, silicon oxide films are used as the insulating films 107 and 114. 11B is the case where the insulating film 107 is provided. The energy of the bottom of the conduction band of the silicon oxide film used is shown, and EcS1 is the energy of the oxide semiconductor film 42 0, and EcS2 is the energy of the bottom of the conduction band of the oxide film 422. EcI2 is the energy of the bottom of the conduction band of the silicon oxide film used as the insulating film 114. - indicates.

[0200] As shown in FIG. 11B, the oxide semiconductor film 420 and the oxide film 422 have a conductive The energy at the lower band edge changes smoothly without any barrier. In other words, it changes continuously. This can also be said to be because the oxide semiconductor film 420 and the oxide film 422 contain a common element. The oxide semiconductor film 420 and the oxide film 422 are mixed by oxygen moving between them. This can be said to be due to the formation of a layer.

[0201] As shown in FIG. 11B, the oxide semiconductor film 420 serves as a well, and the channel region is an oxide. It can be seen that the oxide semiconductor film 420 is formed on the oxide semiconductor film 420. Since the energy of the conduction band minimum of the oxide semiconductor film 422 changes continuously, 0 and the oxide film 422 are in continuous contact.

[0202] As shown in FIG. 11B, the oxide film 422 and the insulating film 114 are adjacent to each other. The insulating film 114 is formed of silicon or carbon, which is an element constituting the insulating film 114, and traps due to impurities or defects. Although a pit level may be formed, the oxide film 422 can be formed in the oxide semiconductor film However, the distance between EcS1 and EcS2 can be increased. When the energy difference is small, electrons in the oxide semiconductor film 420 can overcome the energy difference and be tracked. When electrons are captured in the trap level, they form mi- crons at the interface of the insulating film. A fixed charge is generated, and the threshold voltage of the transistor shifts in the positive direction. Therefore, the energy difference between EcS1 and EcS2 should be 0.1 eV or more, preferably 0. If the value is 15 eV or more, the fluctuation of the threshold voltage of the transistor is reduced, and stable electrical characteristics are obtained. This is preferable because it is sexually active.

[0203] As described above, the structures, methods, etc. described in this embodiment may be different from the structures, methods, etc. described in other embodiments. They can be used in appropriate combinations.

[0204] (Embodiment 6) In this embodiment, a semiconductor device that can be applied to a transistor and a capacitor of one embodiment of the present invention will be described. An example of an oxide semiconductor film that can be used as a gate insulating film will be described.

[0205] <Crystallineness of oxide semiconductor film> The structure of the oxide semiconductor film will be described below.

[0206] Oxide semiconductor films are roughly classified into non-single-crystal oxide semiconductor films and single-crystal oxide semiconductor films. The non-single-crystal oxide semiconductor film is a CAAC-OS (C Axis Aligned Crystal Polycrystalline oxide semiconductor film The oxide semiconductor film includes a film, a microcrystalline oxide semiconductor film, an amorphous oxide semiconductor film, and the like.

[0207] First, the CAAC-OS film will be described.

[0208] The CAAC-OS film is one of the oxide semiconductor films that has multiple crystal parts aligned along the c-axis. .

[0209] The CAAC-OS film was observed under a transmission electron microscope (TEM). When observed under a tron ​​microscope, clear boundaries between the crystals are observed. It is not possible to confirm the grain boundary. It can be said that the AAC-OS film is less susceptible to the decrease in electron mobility caused by grain boundaries.

[0210] The CAAC-OS film was observed by TEM from a direction roughly parallel to the sample surface (cross-sectional TEM observation). When observed, it can be confirmed that metal atoms are arranged in layers in the crystalline part. Each layer of the CAAC-OS film is formed on a surface (also called a surface to be formed) or on a concave surface of the upper surface. The shape reflects the convexity and is aligned parallel to the surface on which the CAAC-OS film is formed or the upper surface.

[0211] On the other hand, the CAAC-OS film was observed by TEM from a direction approximately perpendicular to the sample surface (plane T EM observation reveals that metal atoms are arranged in triangular or hexagonal shapes in the crystalline region. However, no regularity was observed in the arrangement of metal atoms between different crystal regions. do not have.

[0212] Cross-sectional and planar TEM observations revealed that the crystals in the CAAC-OS film had an orientation. It can be seen that this is the case.

[0213] In this specification, "parallel" means that two straight lines are at an angle of -10° or more and 10° or less. Therefore, it also includes the case where the angle is between -5° and 5°. "Perpendicular" refers to two straight lines that form an angle of 80° or more and 100° or less. Therefore, the angle may be between 85° and 95°.

[0214] In addition, most of the crystals in the CAAC-OS film are cubic crystals with sides of less than 100 nm. Therefore, the crystal part in the CAAC-OS film has a side length of 10 This also includes cases where the size fits within a cube of less than 5 nm, or less than 3 nm. However, multiple crystals in the CAAC-OS film are connected to form a single large crystal domain. For example, in a planar TEM image, 2 Over 5μm 2 or more than 1000μm 2 Crystal regions with more than this size may be observed.

[0215] X-ray diffraction (XRD) of the CAAC-OS film When structural analysis is performed using this device, for example, CAAC-OS with InGaZnO4 crystals can be seen. In the out-of-plane analysis of the film, the diffraction angle (2θ) peaks around 31°. This peak is attributed to the (009) plane of the InGaZnO4 crystal. Therefore, the crystals of the CAAC-OS film have a c-axis orientation, and the c-axis faces the surface on which the film is formed or the upper surface. It can be seen that the direction is roughly vertical.

[0216] On the other hand, the in-p X-rays incident on the CAAC-OS film are perpendicular to the c-axis. In the Lane analysis, a peak may appear around 2θ of 56°. The crystal structure of InGaZnO4 is composed of a single crystal of InGaZnO4. In the case of a nitride semiconductor film, 2θ is fixed at around 56°, and the normal vector of the sample surface is the axis (φ axis). When the sample is rotated and analyzed (φ scan), a crystal plane equivalent to the (110) plane is detected. In contrast, in the case of the CAAC-OS film, six peaks are observed, which are assigned to 2θ. Even when the φ is fixed at around 56° and scanned, no clear peak appears.

[0217] From the above, it can be concluded that the orientation of the a-axis and b-axis is uniform between different crystal regions in the CAAC-OS film. Although it is irregular, it has a c-axis orientation, and the c-axis is parallel to the normal vector of the surface on which it is formed or the upper surface. Therefore, the layered structure confirmed by the cross-sectional TEM observation mentioned above is consistent with the Each layer of arranged metal atoms is a plane parallel to the ab plane of the crystal.

[0218] The crystalline part is formed when the CAAC-OS film is formed or after a crystallization treatment such as a heat treatment. As described above, the c-axis of the crystal is aligned with the surface on which the CAAC-OS film is to be formed. Therefore, for example, in the CAAC-OS film, When the shape is changed by etching, the c-axis of the crystal is aligned with the CAAC-OS film. It may not be parallel to the normal vector of the face or top surface.

[0219] Furthermore, the distribution of c-axis oriented crystals in the CAAC-OS film does not need to be uniform. For example, the crystalline part of the CAAC-OS film is grown from the top surface of the CAAC-OS film. Therefore, when the crystal is formed, the region near the top surface has a crystal orientation that is more c-axis oriented than the region near the surface on which the crystal is formed. In addition, when impurities are added to the CAAC-OS film, the proportion of the impurity The region where the material was added is transformed, and regions with different proportions of c-axis oriented crystals are formed. It may also be possible.

[0220] In addition, the out-of-plane structure of the CAAC-OS film with InGaZnO4 crystals In the analysis by the NMR method, in addition to the peak at 2θ near 31°, a peak also appeared at 2θ near 36°. The peak at 2θ around 36° is due to the presence of c-axis orientation in part of the CAAC-OS film. The CAAC-OS film contains crystals that do not have crystalline structure. It is preferable that the peak is exhibited at 2θ of about 36° and that the peak is not exhibited at 2θ of about 36°.

[0221] The CAAC-OS film is an oxide semiconductor film with a low concentration of impurities. The oxide semiconductor film is made of an element other than the main component, such as silicon or a transition metal element. The elements such as ZnO, which have stronger bonding strength with oxygen than the metal elements constituting the oxide semiconductor film, By removing oxygen from the oxide semiconductor film, the atomic arrangement of the oxide semiconductor film is disrupted, and the crystallinity is reduced. In addition, heavy metals such as iron and nickel, argon, and carbon dioxide are Because the diameter (or molecular radius) is large, when the molecule is contained inside the oxide semiconductor film, The impurities contained in the oxide semiconductor film are likely to disturb the atomic arrangement of the oxide semiconductor film, which may result in a decrease in crystallinity. The pure material may act as a carrier trap or a carrier generation source.

[0222] The CAAC-OS film is an oxide semiconductor film with a low density of defect states. Oxygen vacancies in semiconductor films can act as carrier traps and trap hydrogen. This can become a carrier generation source.

[0223] The low impurity concentration and low defect level density (low oxygen vacancies) are called high-purity intrinsic or The term "high-purity intrinsic" refers to a substantially high-purity intrinsic oxide semiconductor. Since the film has a small number of carrier generation sources, the carrier density can be reduced. The transistor using the oxide semiconductor film has electrical characteristics (noise) such that the threshold voltage is negative. It is also called "marine.") It is rare for it to become pure or substantially pure. An intrinsic oxide semiconductor film has few carrier traps. Transistors using this film have little fluctuation in electrical characteristics and are highly reliable. Note that it takes time for the charges trapped in the carrier traps in the oxide semiconductor film to be released. The time is long and the charge may behave as if it is fixed. Therefore, a transistor using an oxide semiconductor film with a high density of defect states has unstable electrical characteristics. This may be the case.

[0224] In addition, the electrical characteristics of transistors using CAAC-OS films are improved by irradiation with visible light or ultraviolet light. There is little gender variation.

[0225] Next, a microcrystalline oxide semiconductor film will be described.

[0226] In the microcrystalline oxide semiconductor film, crystal parts can be clearly seen in the TEM image. The crystal parts contained in the microcrystalline oxide semiconductor film may have a size of 1 nm or more and 100 nm or more. In particular, the size of the particles is between 1 nm and 10 nm. Nanocrystals (nc) are microcrystals with a diameter of 1 nm or less, or 1 nm to 3 nm. The oxide semiconductor film having nc-OS (nanocrystalline O The nc-OS film is called an oxide semiconductor film. In EM observation images, the grain boundaries may not be clearly visible.

[0227] The nc-OS film is a microscopic region (e.g., a region of 1 nm to 10 nm, especially a region of 1 nm or less). The nc-OS film has a periodic atomic arrangement in the region of 3 nm or less. There is no regularity in the crystal orientation between the crystal parts, and therefore no orientation is observed throughout the film. Therefore, the nc-OS film cannot be distinguished from an amorphous oxide semiconductor film depending on the analytical method. For example, XRD, which uses X-rays with a diameter larger than that of the crystal part, is used for nc-OS films. When structural analysis is performed using the device, the crystal plane is analyzed using the out-of-plane method. In addition, the peaks shown in the figure are not detected in the nc-OS film because the probe diameter is larger than that of the crystalline part. Electron beam diffraction (also called selected area electron beam diffraction) using an electron beam (for example, 50 nm or larger) When the diffraction pattern is changed to nc-OS film, a halo-like diffraction pattern is observed. The probe diameter is close to or smaller than the size of the crystal part (for example, 1 nm or more and 30 nm or less). When electron beam diffraction (also called nanobeam electron diffraction) is performed using the electron beam (bottom), Furthermore, when nanobeam electron diffraction is performed on the nc-OS film, a circular pattern is observed. In addition, a bright area (ring-shaped) may be observed for the nc-OS film. When performing nanobeam electron diffraction, multiple spots may be observed within a ring-shaped region. be.

[0228] The nc-OS film is an oxide semiconductor film with higher order than an amorphous oxide semiconductor film. Therefore, the nc-OS film has a lower density of defect states than the amorphous oxide semiconductor film. In the nc-OS film, there is no regularity in the crystal orientation between different crystal parts. The OS film has a higher density of defect states than the CAAC-OS film.

[0229] The oxide semiconductor film may be, for example, an amorphous oxide semiconductor film, a microcrystalline oxide semiconductor film, or a C The AAC-OS film may be a laminate film having two or more kinds of films.

[0230] The oxide semiconductor film included in the transistor and the capacitor of the semiconductor device of one embodiment of the present invention The oxide semiconductor film may have any of the above crystal states. When a semiconductor film is included, the crystal state of each oxide semiconductor film may be different. A CAAC-OS film is used as the oxide semiconductor film that functions as a channel region of the transistor. In addition, the oxide semiconductor film serving as an electrode of a capacitor is preferably Since the impurity concentration in the oxide semiconductor film is higher than that in the oxide semiconductor film contained in the insulating film, the crystallinity might be reduced in some cases.

[0231] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. It is possible.

[0232] (Embodiment 7) In this embodiment, a display device using a semiconductor device of one embodiment of the present invention will be described with reference to FIG. The same functions as those in the first embodiment will be denoted by the same reference numerals. and detailed explanations thereof will be omitted.

[0233] The display device shown in FIG. 12A has a region having pixels of a display element (hereinafter referred to as a pixel portion 302). ) and a circuit section ( hereinafter referred to as a drive circuit section 304), and a circuit having a function of protecting the element (hereinafter referred to as a protection circuit 30 6) and a terminal portion 307. Note that the protection circuit 306 is not provided in the configuration. That's fine.

[0234] A part or the whole of the driver circuit portion 304 is formed on the same substrate as the pixel portion 302. This makes it possible to reduce the number of parts and terminals. When a part or all of the driving circuit is not formed on the same substrate as the pixel portion 302, A part or the whole of the path portion 304 is made of COG (Chip On Glass) or TAB (Tip On Glass). This can be implemented using the APEX Automated Bonding.

[0235] The pixel units 302 are arranged in X rows (X is a natural number of 2 or more) and Y columns (Y is a natural number of 2 or more). The display device has a circuit for driving a plurality of display elements (hereinafter referred to as pixel circuit 301), The path section 304 is a circuit (hereinafter referred to as a gate driver) that outputs a signal (scanning signal) for selecting a pixel. 304a), for supplying signals (data signals) for driving the display elements of the pixels. The source driver 304b includes a driving circuit such as the circuit (hereinafter referred to as a source driver 304b).

[0236] The gate driver 304a includes a shift register and the like. A signal for driving the shift register is inputted through the terminal section 307, and a signal for outputting the shift register is outputted through the terminal section 307. For example, the gate driver 304a receives a start pulse signal, a clock signal, etc. The gate driver 304a receives a scanning signal and outputs a pulse signal. The gate has a function of controlling the potential of the scanning lines GL_1 to GL_X. A plurality of drivers 304a are provided, and the plurality of gate drivers 304a drive the scanning lines GL_1 to Alternatively, the gate driver 304a may control the GL_X by dividing it into two parts. However, the gate driver 30 has a function of supplying 4a may also provide other signals.

[0237] The source driver 304b includes a shift register and the like. Through the terminal section 307, signals for driving the shift register as well as the source of the data signal are transmitted. The source driver 304b receives a signal (image signal) that is to be output from the pixel circuit The source driver 304b has a function of generating a data signal to be written to the source driver 301. A data signal is generated in accordance with a pulse signal obtained by inputting a start pulse, a clock signal, etc. The source driver 304b has a function of controlling the output of a data signal. The data lines DL_1 to DL_Y are connected to the data lines DL_2 through DL_Y. Alternatively, the source driver 304b may have a function of supplying an initialization signal. However, the present invention is not limited to this, and the source driver 304b may also supply other signals. It is possible.

[0238] The source driver 304b is configured using, for example, a plurality of analog switches. The source driver 304b sequentially turns on a plurality of analog switches, The image signal can be time-divided and output as a data signal. The source driver 304b may be configured using the same.

[0239] Each of the plurality of pixel circuits 301 is connected to one of the plurality of scanning lines GL to which a scanning signal is applied. A pulse signal is input via the data line DL, and a data signal is given via one of the data lines DL. A data signal is input to each of the pixel circuits 301. 304a controls the writing and holding of data of the data signal. The second pixel circuit 301 is connected to a gate driver GL_m (where m is a natural number equal to or less than X) via a scanning line GL_m. A pulse signal is input from 304a, and the potential of the data line DL_n ( A data signal is input from the source driver 304b via the input terminal 304a (n is a natural number equal to or less than Y).

[0240] The protection circuit 306 shown in FIG. 12A is, for example, a gate driver 304a and a pixel circuit 3 01. Alternatively, the protection circuit 306 is connected to the scanning line GL, which is the wiring between the source driver The data line DL is connected between the driver 304b and the pixel circuit 301. The protection circuit 306 can be connected to the wiring between the gate driver 304a and the terminal section 307. Alternatively, the protection circuit 306 may be formed on the wiring between the source driver 304b and the terminal section 307. The terminal section 307 can be connected to a power supply and a power supply line from an external circuit to the display device. This refers to the part where terminals for inputting control signals and image signals are provided.

[0241] When a potential outside a certain range is applied to the wiring to which the protection circuit 306 is connected, the protection circuit 306 This is a circuit that brings one wire into electrical continuity with another wire.

[0242] As shown in FIG. 12A, a pixel section 302 and a driver circuit section 304 are provided with a protection circuit 30. 6, ESD (Electro Static Discharge: This can improve the resistance of the display device to overcurrents caused by electrostatic discharges and the like. However, the configuration of the protection circuit 306 is not limited to this. For example, A configuration in which a protection circuit 306 is connected, or a configuration in which the protection circuit 306 is connected to the source driver 304b Alternatively, a configuration in which a protection circuit 306 is connected to the terminal portion 307 may be used. It can also be done as follows.

[0243] In FIG. 12(A), the gate driver 304a and the source driver 304b Therefore, although an example in which the driving circuit portion 304 is formed is shown, the present invention is not limited to this configuration. For example, only the gate driver 304a is formed, and a source driver circuit prepared separately is formed. A substrate (for example, a drive circuit substrate formed of a single crystal semiconductor film or a polycrystalline semiconductor film) is implemented. It may also be configured to be equipped with

[0244] Furthermore, the plurality of pixel circuits 301 shown in FIG. 12(A) may be, for example, a configuration shown in FIG. 12(B). It can be said that:

[0245] The pixel circuit 301 shown in FIG. 12B includes a liquid crystal element 370, a transistor 150, and a capacitor. The transistor 150 and the capacitor 160 are A semiconductor device having the configuration shown in FIG. 1 in the first embodiment can be used.

[0246] The potential of one of the pair of electrodes of the liquid crystal element 370 is set appropriately according to the specifications of the pixel circuit 301. The orientation state of the liquid crystal element 370 is set by the written data. A common potential is applied to one of the pair of electrodes of the liquid crystal element 370 included in each of the pixel circuits 301. A common potential may be applied to the pair of liquid crystal elements 370 of the pixel circuits 301 in each row. One of the electrodes may be given a different potential.

[0247] For example, the display device including the liquid crystal element 370 can be driven in a TN mode, an STN mode, or the like. Mode, VA mode, ASM (Axially Symmetric Aligned Mode) Micro-cell mode, OCB (Optically Compensated Birefringence mode, FLC (Ferroelectric Liquid Crystal id Crystal) mode, AFLC (AntiFerroelectric Li Quid Crystal) mode, MVA mode, PVA (Patterned Ve Vertical Alignment mode, IPS mode, FFS mode, or TBA (Transverse Bend Alignment) mode may also be used. In addition to the above-mentioned driving method, the display device can also be driven by an ECB (Electric Carrier Board) or the like. Ally Controlled Birefringence mode, PDLC (P Polymer Dispersed Liquid Crystal (PNLC) mode (Polymer Network Liquid Crystal) mode, guest However, there are various types of liquid crystal elements and their driving methods, and they are not limited to these. A variety of materials can be used.

[0248] Also, a liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent The liquid crystal element may be configured by the following. The liquid crystal that exhibits the blue phase has a response speed of 1 msec or less. In addition, the liquid crystal that exhibits the blue phase is optically isotropic, so alignment treatment is not required. In addition, the viewing angle dependency is small.

[0249] In the pixel circuit 301 in the mth row and the nth column, the source electrode or the drain electrode of the transistor 150 One of the electrodes is electrically connected to the data line DL_n, and the other is connected to a pair of electrodes of the liquid crystal element 370. The gate electrode of the transistor 150 is electrically connected to the other of the scan lines G L_m. The transistor 150 can be turned on or off. This provides a function of controlling the writing of data signals.

[0250] One of the pair of electrodes of the capacitor 160 is connected to a wiring to which a potential is supplied (hereinafter, a potential supply line VL ) and the other is electrically connected to the other of the pair of electrodes of the liquid crystal element 370. The value of the potential of the potential supply line VL is set appropriately according to the specifications of the pixel circuit 301. The capacitor 160 functions as a storage capacitor for storing written data.

[0251] For example, in a display device having the pixel circuit 301 shown in FIG. 12A, the gate driver 304 The pixel circuits 301 in each row are selected in sequence by a, and the transistors 150 are turned on to output the data. Write the data of the data signal.

[0252] The pixel circuit 301 into which the data has been written is turned off by turning off the transistor 150. By repeating this process for each row, an image can be displayed.

[0253] Although the liquid crystal element 370 is used as the display element in the above example, the present invention is not limited to this embodiment. One aspect of the present invention is not limited to this.

[0254] For example, in this specification, a display element, a display device which is a device having a display element, a light-emitting device, A light-emitting device, which is a device having an element and a light-emitting element, can be used in various forms or in various Examples of a display element, a display device, a light-emitting element, or a light-emitting device include is an EL (electroluminescence) element (EL element including organic and inorganic materials, organic EL EL elements, inorganic EL elements), LEDs (white LEDs, red LEDs, green LEDs, blue LEDs, etc. etc.), transistors (transistors that emit light according to the current), electron-emitting elements, liquid crystal elements, Electronic ink, electrophoretic element, grating light valve (GLV), plasma display ray (PDP), MEMS (Micro Electro Mechanical Systems), Digital Micromirror Device (DMD), DMS (Digital Micro Shutter), IM OD (Interference Modulation) element, electrowetting element , piezoelectric ceramic displays, carbon nanotubes, etc., due to electromagnetic effects. Some have display media that change contrast, brightness, reflectance, transmittance, etc. An example of a display device using an electron-emitting device is an EL display. An example of a display device is a field emission display (FED) or SE D-type flat panel display (SED: Surface-conduction Electro Display devices using liquid crystal elements include An example is a liquid crystal display (transmissive liquid crystal display, semi-transmissive liquid crystal display). , reflective LCD displays, direct-view LCD displays, projection LCD displays, etc. An example of a display device using electronic ink or an electrophoretic element is electronic paper. There is.

[0255] An example in which a liquid crystal element is used as the display element is shown in FIG. A liquid crystal layer is provided between the common electrode and the conductive film 120. 123 is provided.

[0256] Alternatively, an example in which a light-emitting element is used as a display element is shown in FIG. An insulating film 132, a light-emitting layer 125, and a common electrode 124 are provided on the substrate.

[0257] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done.

[0258] (Embodiment 8) In this embodiment, a display module and an electronic device using the semiconductor device of one embodiment of the present invention will be described. This will be explained with reference to FIGS. 13 and 14.

[0259] The display module 8000 shown in FIG. 13 includes an upper cover 8001 and a lower cover 8002. Between them, touch panel 8004 connected to FPC8003 and A display panel 8006, a backlight unit 8007, a frame 8009, a printed circuit board It has a board 8010 and a battery 8011.

[0260] The semiconductor device of one embodiment of the present invention can be used for the display panel 8006, for example.

[0261] The upper cover 8001 and the lower cover 8002 are connected to the touch panel 8004 and the display panel The shape and dimensions can be changed as needed to fit the size of the 8006.

[0262] The touch panel 8004 is a resistive or capacitive touch panel. The display panel 8006 can be used by overlapping it with the opposing substrate (sealing substrate). It is also possible to provide the display panel 8 with a touch panel function. It is also possible to provide an optical sensor in each pixel of 006 to make it an optical touch panel.

[0263] The backlight unit 8007 includes a light source 8008. The light source 8008 is It may be provided at the end of the light unit 8007 and configured to use a light diffusion plate.

[0264] The frame 8009 has a function of protecting the display panel 8006 and also a function of preventing the movement of the printed circuit board 8010. It also functions as an electromagnetic shield to block electromagnetic waves generated by the operation of the The frame 8009 may also function as a heat sink.

[0265] The printed circuit board 8010 includes a power supply circuit, a signal circuit for outputting a video signal and a clock signal. The power supply circuit is provided with a signal processing circuit. Alternatively, the power source may be a battery 8011 provided separately. 1 can be omitted if commercial power is used.

[0266] In addition, the display module 8000 includes components such as a polarizing plate, a retardation plate, and a prism sheet. It may also be provided in addition.

[0267] 14(A) to 14(H) are diagrams showing electronic devices. These electronic devices are housed in a housing. Body 5000, display unit 5001, speaker 5003, LED lamp 5004, operation key 50 05 (including a power switch or an operation switch), a connection terminal 5006, a sensor 5007 ( Force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances , sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, 5008, a microphone 5009, etc. can.

[0268] FIG. 14(A) shows a mobile computer, which includes, in addition to the above, a switch 5009 , an infrared port 5010, etc. FIG. 14(B) shows a portable terminal equipped with a recording medium. A portable image reproducing device (for example, a DVD reproducing device) is also included. The display unit 5002, the recording medium reading unit 5011, etc. It is a group-type display, and in addition to the above, it has a second display unit 5002, a support unit 5012 , earphones 5013, etc. FIG. 14(D) shows a portable gaming machine. In addition to the above, it may have a recording medium reading unit 5011, etc. It is a digital camera with a TV receiving function, and in addition to the above, it also has an antenna 5014, The mobile phone may have a shutter button 5015, an image receiving unit 5016, etc. It is a belt-type gaming machine, and in addition to the above, it has a second display unit 5002, a recording medium reading unit 5011, , etc. FIG. 14(G) shows a television receiver, which, in addition to the above, has It can have a tuner, an image processor, etc. FIG. 14(H) shows a portable television receiver. In addition to the above, it has a charger 5017 capable of transmitting and receiving signals, etc. can be done.

[0269] The electronic devices shown in FIGS. 14A to 14H can have various functions. For example, functions to display various information (still images, videos, text images, etc.) on the display, Panel function, calendar, date or time display function, various software ( It has a function to control processing by a program, a wireless communication function, and various controls using the wireless communication function. Functions for connecting to computer networks, transmitting various data using wireless communication functions, The function of receiving, reading out the program or data recorded on the recording medium and displaying it on the display Furthermore, in an electronic device having multiple display units, In this case, one display section is used mainly to display image information, and another display section is used mainly to display text information. or a function to display images that take parallax into account on multiple displays to create a three-dimensional effect. Furthermore, in electronic devices having an image receiving unit, The camera has the functions to take still images, record videos, and automatically or manually correct captured images. function to correct the image, to save the captured image to a recording medium (external or built-in to the camera), 14A to 14C, and the like. The functions that the electronic device shown in 4(H) can have are not limited to these, and various functions can be It can have.

[0270] The electronic device described in this embodiment has a display unit for displaying some information. It is characterized by the following.

[0271] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done. [Explanation of symbols]

[0272] 102 Circuit Board 102a board 104a Oxide semiconductor film 104b Oxide semiconductor film 106 insulating film 107 Insulating film 108 insulating film 110a Oxide semiconductor film 110b Oxide semiconductor film 112a Source electrode 112b Drain electrode 114 insulating film 116 Insulating film 118 insulating film 118a Insulating film 120 Conductive film 120a Conductive film 121 Conductive film 121a Conductive film 122 insulating film 132 insulating film 140 Aperture 142 Aperture 150 transistors 151 transistors 152 transistors 160 Capacitor 161 Capacitor element 162 Capacitor element 202 Substrate 204 Oxide semiconductor film 204a Oxide semiconductor film 204b Oxide semiconductor film 206 Insulating film 207 Insulating Film 208 insulating film 210 Oxide semiconductor film 212a Source electrode 212b Drain electrode 216 Insulating film 217 Insulating Film 218 Insulating film 220 Conductive film 240 aperture 250 transistors 260 Capacitor 301 Pixel circuit 302 Pixel section 304 Drive circuit section 304a Gate Driver 304b source driver 306 Protection circuit 307 Terminal section 370 Liquid Crystal Devices 410a Oxide laminated film 410b Oxide laminated film 420 Oxide semiconductor film 420a Oxide semiconductor film 420b Oxide semiconductor film 422 Oxide film 422a Oxide film 422b Oxide film 5000 cabinets 5001 Display section 5002 Display section 5003 Speaker 5004 LED lamp 5005 Operation key 5006 Connection terminal 5007 Sensor 5008 Microphone 5009 Switch 5010 Infrared port 5011 Recording medium reading unit 5012 Support part 5013 Earphones 5014 Antenna 5015 Shutter button 5016 Image receiving unit 5017 charger 8000 Display Module 8001 Top cover 8002 Lower cover 8003 FPC 8004 Touch Panel 8005 FPC 8006 Display Panel 8007 Backlight Unit 8008 light source 8009 Frame 8010 Printed Circuit Board 8011 Battery

Claims

1. A semiconductor device including a pixel including a transistor, a capacitor, and a pixel electrode, a first conductive film that functions as one electrode of the capacitor; a first insulating film having a region disposed above the first conductive film; a first oxide semiconductor film having a region disposed above the first insulating film and having a channel formation region of the transistor; a second oxide semiconductor film having a region disposed above the first insulating film and functioning as the other electrode of the capacitor; a second conductive film having a region disposed above the first oxide semiconductor film and electrically connected to the first oxide semiconductor film; a third conductive film having a region disposed above the first oxide semiconductor film and electrically connected to the first oxide semiconductor film; a second insulating film having a region disposed above the first oxide semiconductor film and a region disposed above the second oxide semiconductor film; a third insulating film having a region disposed above the second insulating film and a region disposed above the second oxide semiconductor film; a fourth conductive film that is electrically connected to the second conductive film, has a region that is disposed above the third insulating film, and has a function as the pixel electrode; an upper surface of the second oxide semiconductor film has a region in contact with the second insulating film and a region in contact with the third insulating film; the second oxide semiconductor film does not have a region in contact with the fourth conductive film; Semiconductor device.

2. A semiconductor device including a pixel including a transistor, a capacitor, and a pixel electrode, a first conductive film that functions as one electrode of the capacitor; a first insulating film having a region disposed above the first conductive film; a first oxide semiconductor film having a region disposed above the first insulating film and having a channel formation region of the transistor; a second oxide semiconductor film having a region disposed above the first insulating film and functioning as the other electrode of the capacitor; a second conductive film having a region disposed above the first oxide semiconductor film and electrically connected to the first oxide semiconductor film; a third conductive film having a region disposed above the first oxide semiconductor film and electrically connected to the first oxide semiconductor film; a second insulating film having a region disposed above the first oxide semiconductor film and a region disposed above the second oxide semiconductor film; a third insulating film having a region disposed above the second insulating film and a region disposed above the second oxide semiconductor film; a fourth conductive film that is electrically connected to the second conductive film, has a region that is disposed above the third insulating film, and has a function as the pixel electrode; an upper surface of the first oxide semiconductor film has a region in contact with the second insulating film; an upper surface of the second oxide semiconductor film has a region in contact with the second insulating film and a region in contact with the third insulating film; the second oxide semiconductor film does not have a region in contact with the fourth conductive film; Semiconductor device.

3. A semiconductor device including a pixel including a transistor, a capacitor, and a pixel electrode, a first conductive film that functions as one electrode of the capacitor; a first insulating film having a region disposed above the first conductive film; a first oxide semiconductor film having a region disposed above the first insulating film and having a channel formation region of the transistor; a second oxide semiconductor film having a region disposed above the first insulating film and functioning as the other electrode of the capacitor; a second conductive film having a region disposed above the first oxide semiconductor film and electrically connected to the first oxide semiconductor film; a third conductive film having a region disposed above the first oxide semiconductor film and electrically connected to the first oxide semiconductor film; a second insulating film having a region disposed above the first oxide semiconductor film and a region disposed above the second oxide semiconductor film; a third insulating film having a region disposed above the second insulating film and a region disposed above the second oxide semiconductor film; a fourth conductive film that is electrically connected to the second conductive film, has a region that is disposed above the third insulating film, and has a function as the pixel electrode; the first insulating film includes a first layer containing nitrogen and silicon, and a second layer having a region disposed above the first layer and containing oxygen and silicon; an upper surface of the second oxide semiconductor film has a region in contact with the second insulating film and a region in contact with the third insulating film; the second oxide semiconductor film does not have a region in contact with the fourth conductive film; Semiconductor device.

4. A semiconductor device including a pixel including a transistor, a capacitor, and a pixel electrode, a first conductive film that functions as one electrode of the capacitor; a first insulating film having a region disposed above the first conductive film; a first oxide semiconductor film having a region disposed above the first insulating film and having a channel formation region of the transistor; a second oxide semiconductor film having a region disposed above the first insulating film and functioning as the other electrode of the capacitor; a second conductive film having a region disposed above the first oxide semiconductor film and electrically connected to the first oxide semiconductor film; a third conductive film having a region disposed above the first oxide semiconductor film and electrically connected to the first oxide semiconductor film; a second insulating film having a region disposed above the first oxide semiconductor film and a region disposed above the second oxide semiconductor film; a third insulating film having a region disposed above the second insulating film and a region disposed above the second oxide semiconductor film; a fourth conductive film that is electrically connected to the second conductive film, has a region that is disposed above the third insulating film, and has a function as the pixel electrode; an upper surface of the first oxide semiconductor film has a region in contact with the second insulating film; the first insulating film includes a first layer containing nitrogen and silicon, and a second layer having a region disposed above the first layer and containing oxygen and silicon; an upper surface of the second oxide semiconductor film has a region in contact with the second insulating film and a region in contact with the third insulating film; the second oxide semiconductor film does not have a region in contact with the fourth conductive film; Semiconductor device.

5. In any one of claims 1 to 4, the first oxide semiconductor film and the second oxide semiconductor film contain In, Ga, and Zn as main components; Semiconductor device.

6. In any one of claims 1 to 5, the third insulating film includes at least one of a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, a silicon nitride film, an aluminum oxide film, a hafnium oxide film, a yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film; Semiconductor device.

Images