Semiconductor device

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. Alternatively, the present invention relates to a process, a machine, The present invention relates to a manufacture or composition of matter. The present invention relates 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 amorphous silicon and single crystal silicon formed on a glass substrate. The silicon semiconductor is made of silicon semiconductor such as polycrystalline silicon or polysilicon. Transistors using silicon semiconductors are also used in integrated circuits (ICs).

[0003] In recent years, metal oxides that exhibit semiconducting properties have been used in transistors instead of silicon semiconductors. In this specification, the term "oxide" refers to a metal oxide that exhibits semiconductor properties. 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 using it in switching 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] JP 2007-123861 A [Patent Document 2] JP 2007-96055 A [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 insulating film is made of a conductive film having a thickness of 100 .mu.m.

[0007] In order to increase the capacitance of the capacitive element, the area occupied by the capacitive element must be increased. Specifically, there is a measure 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 is reduced, and the display quality of the image is degraded.

[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 that can It is an object of the present invention to provide a semiconductor device that can be manufactured at low cost. One of the objectives is to provide a device and the like.

[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. Other issues can be extracted 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 insulator 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. one of a pair of electrodes of the capacitor 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 insulating film on the gate electrode. an insulating film, a first oxide semiconductor film on the gate insulating film at a position overlapping with a gate electrode; a source electrode and a drain electrode over the oxide semiconductor film; a second oxide semiconductor film provided 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 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; It is preferable that one of a pair of electrodes of the capacitance element is provided on the same surface as the second oxide semiconductor film. This is a semiconductor device having the following characteristics.

[0013] In each of the above structures, the other of the pair of electrodes of the capacitor is formed using 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 (a) represents f.

[0015] Further, a display device and an electronic device using the semiconductor device having any of the above structures are also included in one embodiment of the present invention. Can be enjoyed. Effect of the Invention

[0016] According to one embodiment of the present invention, there is provided a capacitor having a high aperture ratio and an increased capacitance value. In addition, 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 become apparent from the description in the specification, drawings, claims, etc. It is possible to extract other effects from the descriptions in the claims, etc. [Brief description 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. [Diagram 2] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Diagram 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. [Diagram 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 are diagrams illustrating 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 PREFERRED EMBODIMENTS

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

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

[0021] In addition, ordinal numbers such as 1st, 2nd, etc., used in this specification, etc., are used in order to avoid confusion of components. The number is added for convenience and is not intended to be a numerical limit. The terms can be replaced with "second" or "third" as appropriate for explanation.

[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 is possible to use it.

[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] <Example of semiconductor device configuration> FIG. 1A is a top view of a semiconductor device of one embodiment of the present invention, and FIG. ) corresponds to a cross-sectional view taken along the dashed line AB and the dashed line CD. In FIG. 1A, in order to avoid complication, only a part of the components of the semiconductor device (gate In the figure, the insulating film and other components (e.g., gate insulating film) are omitted.

[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 are overlapped. The first oxide semiconductor film 110a at the position where the first oxide semiconductor film 110a is 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 that functions as a gate insulating film and a first 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 112 are connected to the first oxide semiconductor film 110a. Note that the transistor 150 shown in FIGS. It is a 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. It is preferable that the first oxide semiconductor film 110a and the second oxide semiconductor film 110b each have the same metal element. By configuring the semiconductor film 104a to have the same metal element, It is possible to share the same equipment (film equipment, processing equipment, etc.), 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 have the same metal element and are The second oxide semiconductor film 104a has a lower resistivity than 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 the semiconductor device is used for a capacitor element, the wiring or gate wiring is formed of a metal film. The second oxide semiconductor films 104a and 104b may be connected to the first oxide semiconductor film 104a. By forming the wiring, 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. has.

[0031] The capacitor 160 is a second capacitor having a function as one of a pair of electrodes on the substrate 102. The first oxide semiconductor film 104b and the second oxide semiconductor film 104b function as a dielectric film. a portion of the insulating film 108 overlapping with the second oxide semiconductor film 104b with the insulating film 108 interposed therebetween; a first oxide semiconductor film 110b having a function 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 having a function 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 the figure, 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] In addition, 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 material having a light-transmitting property. By doing so, it is possible to form a large area in an area other than the area where the transistor is formed in the pixel. 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 utilizing 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 that contains 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 The resistivity of the first oxide semiconductor film and the second oxide semiconductor film included in the first oxide semiconductor film 160 is controlled. 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 a 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. The resistivity is lower than that of the conductive film 110a.

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

[0037] <Method of controlling resistivity of oxide semiconductor> The first oxide semiconductor films 110a and 110b and the second oxide semiconductor films 104a and 10 The oxide semiconductor film that can be used for 4b has oxygen vacancies and / or hydrogen or water in the film. It is a semiconductor material whose resistivity can be controlled by the impurity concentration. The first oxide semiconductor films 110a and 110b and the second oxide semiconductor films 104a and 104 b) Treatment that increases oxygen deficiency and / or impurity concentration, or By selecting a process that reduces the degree of oxidation, the respective oxide semiconductors formed in the same process can be The resistivity of the membrane can be controlled.

[0038] Specifically, a second oxide semiconductor film 110 serving as a gate electrode of the transistor 150 is 04a, a second oxide semiconductor film 104b which functions 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 does not contain 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 a structure in which the insulating film 106 containing hydrogen is provided by providing the insulating films 107, 114, and 116. At least one of the insulating films 107, 114, and 116 is not in contact with the insulating film 118. In other words, an insulating film capable of releasing oxygen is used to form 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 filled and the film has a high resistivity. In addition, examples of insulating films capable of releasing oxygen include silicon oxide films, 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. Using techniques such as plasma immersion ion implantation, hydrogen, boron, and lithium are implanted. 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 performed using a rare gas (He, Ne, A Plasma treatment using a gas containing one of the following: r, Kr, Xe), hydrogen, and nitrogen. More specifically, plasma treatment in an Ar atmosphere and a mixed gas of Ar and hydrogen are Plasma treatment in an Ar atmosphere, plasma treatment in an ammonia atmosphere, and plasma treatment in an Ar and ammonia atmosphere Examples of suitable plasma treatment methods include plasma treatment in a mixed gas atmosphere of 1000 nm or 1000 nm, and plasma treatment in a nitrogen atmosphere. can be done.

[0042] By the above plasma treatment, the oxide semiconductor film is formed into a lattice from which oxygen has been desorbed (or This creates oxygen vacancies in the area where the oxide is removed. These oxygen vacancies can be a factor in generating carriers. In addition, in the vicinity of the oxide semiconductor film, more specifically, under or on the oxide semiconductor film, When hydrogen is supplied from the insulating film in contact with the upper side, the oxygen vacancies and hydrogen combine to form the In some cases, electrons that are carriers are generated.

[0043] On the other hand, an oxide semiconductor film in which oxygen vacancies are filled and the hydrogen concentration is reduced is highly purified and intrinsic. Alternatively, it can be said that the oxide semiconductor film is substantially highly purified and 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, it is 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, so that the carrier density can be reduced. In addition, a highly-purified intrinsic or substantially highly-purified intrinsic oxide semiconductor film can have a high density of defect states. Since the degree of diffusion 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 element 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 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 the insulating film 104b. By using an insulating film containing hydrogen like the film 106, the first oxide semiconductor film 110b can be prevented from containing hydrogen. The insulating film capable of releasing hydrogen is a film containing water. The elemental concentration is 1×10 22 atoms / cm 3 It is preferable that the insulating film is more than 1000 nm. 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 manner, hydrogen can be effectively contained in the second oxide semiconductor film 104. a, 104b, and the insulating film in contact with the first oxide semiconductor film 110b. In this way, the resistivity of the oxide semiconductor film can be controlled.

[0046] Hydrogen contained in the oxide semiconductor film reacts with oxygen that is bonded to metal atoms to form water. In this case, oxygen vacancies are formed in the lattice from which oxygen has been desorbed (or in the portion from which oxygen has been desorbed). When hydrogen enters the electron carrier, it can generate electrons. When it bonds with oxygen, which bonds with a metal atom, it may generate electrons, which act as carriers. 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 larger than the first oxide semiconductor film 110a. In this case, 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 to be formed is It is preferable that the amount of the oxide semiconductor film 11 is as small as possible. In 0a, secondary ion mass spectrometry (SIMS) was used. The hydrogen concentration obtained by spectrometry was calculated as 2×10 20 atoms / cm 3 Less than or equal to 5×10 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 a gate electrode of the transistor 150 and an electrode of the capacitor 160 The oxide semiconductor films 104a and 104b and the oxide semiconductor serving as electrodes of the capacitor 160 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 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 each contain the same metal element. The oxide semiconductor films 104a and 104b each 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 the same metal element but have different compositions. For example, during the manufacturing process of a transistor and a capacitor, In some cases, elements are removed, 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 By forming the conductive film on the same surface, it is possible to reduce manufacturing costs. A conductive film functioning as a gate electrode of a transistor and a conductive film functioning as an electrode of a capacitor element The oxide semiconductor film is subjected to an appropriate treatment to obtain a film having a thickness of 100 nm to 150 nm. A conductive film having low resistivity and light-transmitting properties can be obtained. In this case, the transistor and / or the capacitor element 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 sa A fire substrate or the like may be used as the substrate 102. Also, a material such as silicon or silicon carbide may be used. Single crystal semiconductor substrates, polycrystalline semiconductor substrates, compound semiconductors such as silicon germanium, etc. It is also possible to use a substrate, an SOI substrate, or the like, on which a semiconductor element is provided. The substrate 102 may be a glass substrate. If you have 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 the 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. The materials used for bonding include plastics that can be used for bonding, and synthetic resins that have flexibility, such as acrylic. Examples of the film include polypropylene, polyester, polyvinyl fluoride, or poly Examples of the base film include polyester, polyamide, and poly Imide, inorganic deposition film, or paper. In particular, semiconductor substrates, single crystal substrates, or By manufacturing transistors using SOI substrates, etc., the characteristics, size, or shape To manufacture transistors with small size, high current capability, and little variation in the By configuring a circuit using such transistors, the power consumption of the circuit can be reduced. This allows for high circuit integration.

[0054] In addition, a transistor is formed on one substrate, and then the transistor is transferred to another substrate. The transistor may be placed on one substrate and the transistor may be placed on another substrate. Examples include substrates on which the above-mentioned transistors can be formed, as well as paper substrates, ceramic substrates, etc. Fan board, stone board, wood board, cloth board (natural fibers (silk, cotton, hemp), synthetic fibers (nylon , polyurethane, polyester) or regenerated fibers (acetate, cupra, rayon, (including recycled polyester), leather substrates, or rubber substrates. By using this, it is possible to form transistors with good characteristics and transistors with low power consumption. It is possible to manufacture devices that are less likely to break, have heat resistance, and are lighter 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 10 4b is at least indium (In), zinc (Zn) and M (Al, Ti, Ga, Y, Zr, La, Ce, Sn or Hf (metals such as In-M-Zn oxide) It is preferable that the oxide contains both In and Zn. In order to reduce the variation in the electrical characteristics of transistors using oxide semiconductors, It is preferred to include a stabilizer.

[0056] The stabilizer includes the metals listed above under M, such as gallium (Ga), sulphuric acid (SA), and gallium (Ga). Sn, Hf, Al, or Zr Other stabilizers include the lanthanide lanthanum (La). , 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 10 Examples of the oxide semiconductor constituting 4b include In-Ga-Zn oxide, In-Al- Zn-based oxide, In-Sn-Zn-based oxide, In-Hf-Zn-based oxide, In-La-Z n-type oxide, In-Ce-Zn-type oxide, In-Pr-Zn-type oxide, In-Nd-Zn In-Sm-Zn oxide, In-Eu-Zn oxide, In-Gd-Zn oxide Oxide, In-Tb-Zn oxide, In-Dy-Zn oxide, In-Ho-Zn oxide oxides, In-Er-Zn oxides, In-Tm-Zn oxides, In-Yb-Zn oxides In-Lu-Zn ​​oxide, In-Sn-Ga-Zn oxide, In-Hf-Ga- Zn-based oxide, In-Al-Ga-Zn-based oxide, In-Sn-Al-Zn-based oxide, I n-Sn-Hf-Zn oxide and In-Hf-Al-Zn oxide can be used. .

[0058] In this case, the In-Ga-Zn oxide is an oxide having In, Ga, and Zn as main components. The ratio of In, Ga, and Zn does not matter. Metal elements other than n may be present.

[0059] In addition, the first oxide semiconductor films 110a and 110b, the second oxide semiconductor film 104a, The first oxide semiconductor film 110 includes the same metal element as the oxides described above. a and 110b, and 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 semiconductor target, the etching gas for processing the oxide semiconductor film can be The etching solution can be used in common.

[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 of silicon oxide by plasma CVD, sputtering, or the like. Con film, silicon oxynitride film, silicon oxynitride film, silicon nitride 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. It is more preferable to have a region containing an excess of 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. 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 obtained. Hafnium oxide has a higher dielectric constant than silicon oxide and silicon oxynitride. Therefore, the physical thickness can be made larger than the equivalent oxide thickness, so the equivalent oxide thickness can be increased to 10n. Even if the thickness is reduced to less than 100 μm or 5 nm, 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-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 is The silicon oxide film is formed as a result of the above. 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 it is suitable for transistors. The insulating film 108 functions as a gate insulating film of the transistor 150 and a dielectric film of the capacitance element 160. By including the silicon nitride film, the insulating film can be physically thickened. , the decrease in the withstand voltage of the transistor 150 and the capacitance element 160 is suppressed, and further, the withstand voltage 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 Metals consisting of tantalum, silver, tungsten, or alloys with these as the main components. Gold can be used as a single layer or as a multilayer structure. For example, a thin film of titanium on an aluminum film. Two-layer structure with a titanium film laminated on a tungsten film, two-layer structure with a titanium film laminated on a tungsten film, A two-layer structure in which a copper film is laminated on a silicon film, and a copper film is laminated on an alloy film containing molybdenum and tungsten a bilayer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film; A titanium film or titanium nitride film and an aluminum film overlaid on the titanium film or titanium nitride film. A three-layer structure is formed by laminating a titanium film or a copper film on top of the titanium film or a titanium nitride film. A molybdenum film or a molybdenum nitride film and the molybdenum film or the 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. A three-layer structure in which a molybdenum film is formed is also available. When the electrode 112b has a three-layer structure, the first and third layers are made of titanium, titanium nitride, and molybdenum. Molybdenum, tungsten, alloys containing molybdenum and tungsten, molybdenum and zirconium A film made of an alloy containing copper, aluminum, gold, or molybdenum nitride is formed on the second layer. Alternatively, it is preferable to form a film made of a low resistance material such as silver or an alloy of copper and manganese. A transparent conductive material containing indium oxide, tin oxide, or zinc oxide may also be used. Materials that can be used for the source electrode 112a and the drain electrode 112b include, for example, The insulating film can be formed by using 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 is formed by a plasma CVD method, a sintered body, or the like. 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 The insulating layer may include at least one of a cerium oxide film and a neodymium oxide film. can.

[0066] Note that in the capacitor 160, the insulating film 118 functions as an electrode of the capacitor 160. The insulating layer 114 also functions to reduce 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 a film having a stoichiometric composition. It is an insulating film having 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, etc. The implantation method, the 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 transistor 150. Therefore, the amount of oxygen vacancies in the first oxide semiconductor film 110a can be reduced. The surface temperature of the heating treatment is 100°C or more and 700°C or less, preferably 100°C or more and 500°C or less. The oxygen concentration measured by thermal desorption spectrometry (TDS) is The amount of molecules released is 1.0×10 18 molecules / cm 3 By using the insulating film having the above properties, 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 to 150 nm, preferably 5 nm to 50 nm. 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 films 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 dashed line. In the embodiment, the two-layer structure of the insulating film 114 and the insulating film 116 has been described. For example, the insulating film 114 may have a single layer structure, the insulating film 116 may have a single layer structure, or the insulating film 116 may have 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 first and second electrodes a. An example of this case is shown in FIGS. 17(A) and 17(B). The source electrode 112a, the drain electrode 112b, and the first oxide semiconductor film 110a 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] <Manufacturing method of 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. 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 electrode of the first electrode is formed on the substrate 1. 02 and the second oxide semiconductor films 104a and 104b are covered with insulating films 106 and 107. The border membrane 108 is formed (see FIG. 2(A)).

[0074] Note that 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 (metal with In:Ga:Zn=1:1:1). An oxide target capable of releasing hydrogen was used as the insulating film 106. The insulating film 107 is a silicon nitride film capable of releasing oxygen. A silicon membrane is used.

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

[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 the unnecessary region is removed. It is formed by etching.

[0077] Next, a gate electrode including the second oxide semiconductor film 104a is formed on the insulating film 108. 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 a 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 (metal with 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 the oxide semiconductor film is formed, it is patterned so that a desired region of the oxide semiconductor film remains, and then an unnecessary region is removed. The insulating layer is formed by etching the area.

[0080] The first oxide semiconductor film 110a and the first oxide semiconductor film 110b are made of the same oxide. Since the metal oxide semiconductor film is processed, the metal oxide semiconductor film contains 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 (a region exposed from the first oxide semiconductor films 110a and 110b) is The film thickness may decrease due to etching of the insulating layer.

[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. to 650° C., preferably 300° C. to 500° C., more preferably is at a temperature between 350℃ and 450℃, in an inert gas atmosphere, and with oxidizing gas at 10ppm or more. The heat treatment may be performed in an atmosphere containing an inert gas or a reduced pressure atmosphere. After the heat treatment in air, oxygen desorbed from the first oxide semiconductor films 110a and 110b is removed by To compensate for this, the heat treatment may be performed in an atmosphere containing 10 ppm or more of oxidizing gas. At least the insulating films 106 and 107 and the first oxide semiconductor films 110a and 110b are The heat treatment can also remove impurities such as hydrogen and water from the first oxide. This may be performed 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 above-mentioned electrical characteristics, impurities in the first oxide semiconductor film 110a are reduced, 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 first oxide semiconductor film 110a are formed on the insulating film 108 and the first oxide semiconductor film 110a. And the 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 a three-layered structure consisting of a titanium film, an aluminum film, and a 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 capable of this 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 an 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 may be, for example, a dry etching method. The method for forming the opening 140 is not limited to this, and may be a wet etching method or a dry etching method. A combination of dry etching and wet etching may also be used. The etching process for forming the opening 140 exposes the first oxide semiconductor film 110b. The film thickness may decrease.

[0089] After that, it is preferable to perform a heat treatment. A part of oxygen contained in the film 116 is transferred to the first oxide semiconductor film 110a to form a first oxide semiconductor film. 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 was performed under the conditions of the heat treatment after the formation of the first oxide semiconductor films 110a and 110b. The process can be the same.

[0090] Next, the insulating film 116 and the first oxide semiconductor film 110b are formed so as to cover the opening 140. Then, 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 FIG. 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 1×10-3 Ωcm or more 1×10 4 Less than Ωcm, more preferred For example, 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 method for preventing impurities from entering the transistor, such as water, alkali metals, and alkaline earth metals. This also has the effect of preventing the diffusion of the oxide semiconductor into the first oxide semiconductor film 110a included in the first oxide semiconductor film 110a.

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

[0094] In addition, the capacitor 160 is formed 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. 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 element 160 are formed on the same substrate. It is possible.

[0096] 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 combination.

[0097] (Embodiment 2) In this embodiment, a semiconductor device according to one embodiment of the present invention will be described. The modified example of the device will be described with reference to Figs. 4 to 6. The same reference numerals 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. ) corresponds to a cross-sectional view taken along a line EF and a line GH. In FIG. 4A, in order to avoid complication, only a part of the components of the semiconductor device (gate In the figure, the insulating film and other components (e.g., gate insulating film) are omitted.

[0099] The semiconductor device illustrated 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 104 a 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 are overlapped. The first oxide semiconductor film 110a at the position where the first oxide semiconductor film 110a is folded and the source on the first oxide semiconductor film 110a are The source electrode 112a and the drain electrode 112b are shown in FIG. 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 an opening that reaches 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 has a function 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. The first oxide semiconductor film 104b and the second oxide semiconductor film 104b function as a dielectric film. The insulating films 108, 114, 116, and 118 are The other electrode of the pair of electrodes overlaps with the second oxide semiconductor film 104b through an intermediate electrode. That is, the conductive film 120 has a function as a pixel electrode. The capacitor has a function as a gate 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 embodiment, insulating films 114, 116, and 118 are provided as part of the dielectric film. However, the present invention is not limited to this. 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 capacitance element 161 may be removed. .

[0104] In addition, 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 manner, the capacitance 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 with 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 that contain 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 forming the insulating film in contact with the capacitance element 161 as the insulating film having the above-mentioned structure, The first oxide semiconductor film and the second oxide semiconductor film included in the transistor 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 device and the conventional semiconductor device is that the other electrode of the capacitor element 161 is a conductive film 120. In this manner, 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 By forming the conductive film on the same surface, it is possible to reduce manufacturing costs. A conductive film functioning as a gate electrode of a transistor and a conductive film functioning as an electrode of a capacitor element The oxide semiconductor film is subjected to an appropriate treatment to obtain a film having a thickness of 100 nm to 150 nm. A conductive film having high conductivity and light-transmitting properties can be obtained. In this case, the transistor and / or the capacitor element 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 first and second electrodes a. An example of this case is shown in FIGS. 18(A) and 18(B). vinegar.

[0110] The conductive film 120 was formed 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 at the same time, etched at the same time, and formed at the same time, they have the same material. Therefore, an increase in the number of process steps can be suppressed. The conductive film 120a may be formed in a process different from that of the conductive film 120. The conductive film 120a has a region overlapping with a channel region of a 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 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 advisable to use a material containing one of zinc (Zn) and tin (Sn). The film 120 may be, for example, indium oxide containing tungsten oxide, tungsten oxide, 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 fluorine, can be used. The conductive film 120 can be formed by, for example, a sputtering method. do.

[0113] <Manufacturing method of 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. 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 FIG. 5(A)).

[0115] Next, a gate electrode including the second oxide semiconductor film 104a is formed on the insulating film 108. 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 regions remain, and then the unnecessary regions are etched away. It is formed by

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

[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 etched away the unwanted areas. A source electrode 112a and a drain electrode 112b are formed on the first oxide semiconductor film 110a. (See FIG. 5(C)).

[0120] Next, the insulating film 108, the first oxide semiconductor film 110a, the source electrode 112a, and the drain electrode 112b are 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 opening, 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 forming method that combines a chipping method and a 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 Then, patterning and etching are performed so that a conductive region remains, forming a conductive film 120 (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 film 121 may be provided so as to overlap with a channel region of a 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 to the input terminals.

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

[0128] 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 combination.

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

[0130] <Configuration Example of Semiconductor Device (Modification 2)> FIG. 7A is a top view of a semiconductor device of one embodiment of the present invention, and FIG. ) corresponds to a cross-sectional view taken along the line IJ and the line KL. In FIG. 7A, in order to avoid complication, only a part of the components of the semiconductor device (gate In the figure, the insulating film and other components (e.g., gate insulating film) are omitted.

[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 104 a 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 are overlapped. The first oxide semiconductor film 110a at the position where the first oxide semiconductor film 110a is folded and the source on the first oxide semiconductor film 110a are The source electrode 112a and the drain electrode 112b are shown in FIG. 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 an opening that reaches 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 has a function 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 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 result is a first oxide semiconductor film 110b.

[0135] In this way, by providing an additional electrode between the pair of electrodes, the area of ​​the capacitance element can be reduced. The capacitance can be increased without increasing the capacitance of the capacitor 162. The capacitor 162 has a structure in which the second oxide semiconductor film 104b and the first 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 serves as a gate insulating film in the transistor 152. In the capacitance element 162, the insulating film 11 functions as a part of the dielectric film. The layers 4, 116, and 118 function as protective insulating films in the transistor 152. The insulating film 118 functions as a part of the dielectric film in the capacitive element 162 .

[0137] In addition, 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, The capacitive element and the conductive film 120 are each made of a material having light-transmitting properties. Since the electrode 162 has a light-transmitting property, the electrode 162 can be formed in a region other than the region where the transistor is formed in the pixel. Since it can be formed large (large area), it is a semiconductor device that increases 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 that contain 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-mentioned 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 transistor 152 and the capacitor 162 The resistivity of the film can be controlled.

[0139] Note that 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 capacitance element 162 .

[0141] In the semiconductor device according to one embodiment of the present invention, a conductive film serving as a gate electrode of a transistor is 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 manufacturing costs. The conductive film functioning as the gate electrode of the capacitor and the conductive film functioning as the electrode of the capacitor are made of oxide. The oxide semiconductor film is subjected to appropriate treatment to have high conductivity. By using the conductive film, a transistor can be formed. 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 that shown in FIGS. The semiconductor device shown in FIG. 4A and the method for manufacturing the semiconductor device shown in FIG. 4B are combined. This allows it to be formed.

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

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

[0145] 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 combination.

[0146] (Embodiment 4) In this embodiment, a semiconductor device according to one embodiment of the present invention will be described. A modified example of the device will be described with reference to Figs. 8 to 10. The same reference numerals are used to denote parts having the same functions as those shown in FIG. 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. ) corresponds to a cross-sectional view taken along a line MN and a line OP. In FIG. 8A, in order to avoid complication, only a part of the components of the semiconductor device (gate In the figure, the insulating film and other components (e.g., gate insulating film) are omitted.

[0148] The semiconductor device shown in FIGS. 8A and 8B includes a first oxide semiconductor film 210 and a second oxide semiconductor film 212. A transistor 250 including a semiconductor film 204a and a capacitive element including an insulating film between a pair of electrodes. In the capacitor 260, one of a 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 a conductive film 220 .

[0149] The transistor 250 includes an insulating film 216 on the substrate 202 and a first oxide layer 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 08 and the second oxide semiconductor film 210 on the insulating film 208 at a position overlapping with the first oxide semiconductor film 210. The transistor shown in FIGS. The transistor 250 has a so-called top gate structure.

[0150] In addition, a gate insulating film including the second oxide semiconductor film 204a is formed on the transistor 250. 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 has a function 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 having a function as one of a pair of electrodes over the insulating film 208 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 having a function 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. The insulating films 218 and 217 function as protective insulating films in the transistor 250. In 260, it functions as a part of the dielectric film. In the above, the insulating films 218 and 217 are provided as part of the dielectric film. For example, in the manufacturing process of the transistor 250, A portion of the insulating films 218 and 217 may be 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 manner, when the capacitor 260 has a light-transmitting property, the transistor in the pixel Since it can be formed large (over a large area) in areas other than the area where it is to be formed, the aperture ratio can be increased. As a result, a semiconductor device having excellent 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 the insulating films 207 and 218 contain at least hydrogen. The insulating films 216, 206, and 217 are made of insulating films that contain 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 capacitance element 260 as the insulating film having the above-mentioned configuration, 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 and the second oxide semiconductor film 204b is higher than that of the first 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 described below.

[0157] <Method 2 for controlling the resistivity of oxide semiconductor> The first oxide semiconductor film 210 and the second oxide semiconductor films 204a and 204b are formed using The oxide semiconductor capable of being formed has oxygen vacancies and / or impurity concentrations such as hydrogen and water in the film. Therefore, the first oxide semiconductor is a semiconductor material whose resistivity can be controlled by the The conductive film 210 and the second oxide semiconductor films 204a and 204b are oxygen deficient and / or impurities are formed. 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 serving as a gate electrode of the transistor 250 04a, an oxide semiconductor film 204b serving as an electrode of the capacitor 260 a plasma treatment is performed 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 a 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 serving as a channel formation region of the transistor 250 10, by providing the insulating films 216 and 206, the insulating film 218 containing hydrogen is not in contact with the insulating film 218. In addition, at least one of the insulating films 216 and 206 is capable of releasing oxygen. By using an insulating film capable of oxidizing the oxide semiconductor film, oxygen can be supplied to the first oxide semiconductor film 210. In the first oxide semiconductor film 210 to which oxygen is supplied, oxygen vacancies in the film or at the interface are filled. As an insulating film capable of releasing oxygen, 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 By forming the conductive film on the same surface, it is possible to reduce manufacturing costs. A conductive film functioning as a gate electrode of a transistor and a conductive film functioning as an electrode of a capacitor element The oxide semiconductor film is subjected to an appropriate treatment to obtain a film having a thickness of 100 nm to 150 nm. A conductive film having high conductivity and light-transmitting properties can be obtained. In this case, the transistor and / or the capacitor element 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 may be made of any 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] <Production method of display device (variation 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. Let's explain using 0.

[0167] First, an insulating film 216 is formed over a substrate 202, and an oxide semiconductor film is formed over the insulating film 216. Then, the oxide semiconductor film is patterned so that a desired region remains, and then unnecessary regions are removed. The first 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 areas are then patterned, and the unnecessary areas are then 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 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 membrane 204 is patterned to leave desired areas and then etched away unwanted areas. In this manner, second oxide semiconductor films 204a and 204b are formed. The insulating films 206 and 207 below the conductor films 204a and 204b are also etched at the same time, and are divided into islands. These are insulating films 206 and 207 that 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 pattern is then formed so that the unnecessary area is etched away, forming an opening 240. 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 a desired area of ​​the conductive film remains, and then the unnecessary area is removed. The conductive film 220 is formed by etching (see FIG. 10C).

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

[0175] 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 combination.

[0176] (Embodiment 5) In this embodiment, a semiconductor device according to one embodiment of the present invention will be 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 140 described in Embodiment 1. The first oxide semiconductor films 110a and 110b of the substrate 160 are stacked with the oxide stacked films 410a and 410b. Therefore, the other components are the transistor 150 and the capacitor element 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 the 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 2 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 and Zn≧M. The atomic ratio of the metal elements in such a sputtering target is preferably as follows: 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 of In is 100 atomic %, the atomic ratio of In to M is preferably 25 atomic %. % 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 and the energy of the bottom of the conduction band of the oxide semiconductor film 420 are 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 .15eV or more and 2eV or less, 1eV or less, 0.5eV or less, or 0.4eV or less It is.

[0186] The oxide film 422 has the above element M in a higher atomic ratio than In, and thus 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 hard.

[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 and M is preferably 50 atomic % In. less than 50 atomic %, M is 50 atomic % or more, and 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), Compared with the conductor film 420, the atomic ratio of M contained in the oxide film 422 is large, typically The amount of the atoms contained in the oxide semiconductor film 420 is 1.5 times or more, preferably 2 times as large as that of the atoms contained in the oxide semiconductor film 420. The atomic ratio is more preferably 3 times or more higher.

[0189] The oxide film 422 is In:M:Zn=x1:y1:z1 [atomic ratio], and the oxide semiconductor If the film 420 has an atomic ratio of In:M:Zn=x2:y2:z2, then y1 / x1 is y 2 / x2, and preferably, y1 / x1 is 1.5 times or more larger than y2 / x2. More preferably, y1 / x1 is at least twice as large as y2 / x2, and even more preferably, In this case, in the oxide semiconductor film 420, y1 / x1 is three times or more larger than y2 / x2. When y2 is equal to or larger than x2, a transistor including an oxide semiconductor can have stable electrical characteristics. However, if y2 is three times or more larger than x2, it is necessary to use an oxide semiconductor. 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 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 the formed oxide film 422 is The atomic ratio of the metal elements contained in the sputtering target is included as an error. Includes fluctuations of ±20%.

[0191] In addition, the semiconductor characteristics and electrical characteristics (field effect) of the required transistors are not limited to these. It is sufficient to use a material with an appropriate composition according to the required properties (e.g., the resultant 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 The concentration of metals, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc. are appropriately adjusted. It is preferred.

[0192] The oxide film 422 is formed by oxidizing 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 from 3 nm to 100 nm, preferably from 3 nm to 50 nm.

[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) The concentration of 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, an alkali metal ion concentration 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 × 10 16 atoms / cm 3 The following are the alkali metals and alkaline earth metals: When a compound is bonded to an oxide semiconductor, carriers may be generated, increasing the off-state current of a transistor. For this reason, the alkali metal or alkali metal in the oxide semiconductor film 420 may be It is preferable to reduce the concentration of alkaline earth metals.

[0195] When the oxide semiconductor film 420 contains nitrogen, electrons serving as carriers are generated, and The carrier density increases and it becomes easier to make the material n-type. Therefore, the transistor having the oxide semiconductor film 420 tends to be normally on. In the present invention, it is preferable that the nitrogen content is reduced as much as possible. For example, in the case of secondary ion mass spectrometry, The nitrogen concentration obtained by the method is 5×10 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. A continuous junction (here, a structure in which the energy at the bottom of the conduction band changes continuously between each film) That is, the oxide semiconductor is formed at the interface of each film. The stacking layer is free of impurities that may form defect levels such as trip centers or recombination centers. Assume that impurities exist between the 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 exposing it to the air. Each chamber in the sputtering apparatus 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 pump (5×10 -7 Pa~1×10 -4 It is preferable to use a temperature of up to about 1 Pa. Alternatively, a turbo molecular pump and cold trap can be combined to evacuate the chamber from the exhaust system. It is preferable to prevent gas, especially gas 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. 11B shows a part of the band structure of the oxide laminate film and the insulating film in contact with the oxide laminate film. Here, silicon oxide films are used as the insulating film 107 and the insulating film 114. In addition, EcI1 shown in FIG. The energy of the conduction band minimum of the silicon oxide film used is shown, and EcS1 is the oxide semiconductor film 42 0, and EcS2 is the energy 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 is because the oxide semiconductor film 420 and the oxide film 422 contain a common element. In addition, oxygen is transferred between the oxide semiconductor film 420 and the oxide film 422, resulting in mixing. 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 with each other.

[0202] As shown in FIG. 11B, in the vicinity of the interface between the oxide film 422 and the insulating film 114, The trapping due to impurities or defects such as silicon or carbon, which are constituent elements of the insulating film 114, Although a sublevel may be formed, the oxide film 422 is provided to 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 exceed the energy difference and are tracked. When electrons are captured in the trap level, they form mili- ums at the interface with the insulating film. This generates a fixed charge, 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 capacitance is set to 15 eV or more, the fluctuation of the threshold voltage of the transistor is reduced, and the electrical characteristics are stabilized. This is preferable because it is sexually active.

[0203] 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 combination.

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

[0205] <Crystallization 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 called CAAC-OS (C Axis Aligned Crystal-Oxide Semiconductor Film). (stalline oxide semiconductor) film, polycrystalline oxide semiconductor The oxide semiconductor film includes a film, a microcrystalline oxide semiconductor film, an amorphous oxide semiconductor film, and the like.

[0207] First, we will explain the CAAC-OS film.

[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 using a quartz crystal microscope, clear boundaries between crystal parts were observed, i.e. 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 the metal atoms are observed, it can be confirmed that they are arranged in layers in the crystal part. Each layer of the CAAC-OS film is formed on a surface on which the film is to be formed (also called a surface on which the film is to be formed) or on a concave surface on the upper surface. The shape reflects a 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 roughly perpendicular to the sample surface (plane T EM observation reveals that metal atoms are arranged in triangular or hexagonal shapes in the crystals. 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...

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

[0214] In addition, most of the crystals in the CAAC-OS film are cubic with a side length of less than 100 nm. The size is small enough to fit inside the body. Therefore, the crystal part in the CAAC-OS film has a side length of 10 This includes sizes that fit within a cube of less than 3 nm, 5 nm, or 5 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 More than 5μm 2 More than or equal to 1000μm 2 In some cases, crystal regions having more than this amount may be observed.

[0215] X-ray diffraction (XRD) of CAAC-OS film When the structure was analyzed using the device, for example, CAAC-OS with InGaZnO4 crystals was In the out-of-plane analysis of the film, the diffraction angle (2θ) peaked at 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 it is oriented in a roughly vertical direction.

[0216] On the other hand, in-p X-rays are incident on the CAAC-OS film from a direction approximately perpendicular to the c-axis. In the lane method, a peak may appear at 2θ around 56°. is attributed to the (110) plane of the InGaZnO4 crystal. 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 Even when the φ is fixed at around 56° and scanned, no clear peak appears.

[0217] From the above, it is considered 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 in 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 process such as a heat treatment. As described above, the c-axis of the crystal is aligned to the surface on which the CAAC-OS film is to be formed. 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 face or top surface normal vector.

[0219] In addition, the distribution of the c-axis oriented crystal parts in the CAAC-OS film may not be uniform. For example, the crystals in the CAAC-OS film grow from the top surface of the CAAC-OS film. Therefore, when the crystal is formed, the region near the top surface has more c-axis oriented crystals 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 impurities may increase. The region where the material was added changed in quality, and regions with different proportions of c-axis oriented crystals were formed. It may also be possible.

[0220] In addition, the out-of-plane crystal structure of the CAAC-OS film with InGaZnO4 crystals In the analysis by the method, in addition to the peak at 2θ near 31°, a peak also appeared at 2θ near 36°. The peak at 2θ of around 36° may be due to the c-axis orientation in some parts of the CAAC-OS film. The CAAC-OS film contains crystals that do not have the 2θ value of about 31°. It is preferable that the spectrum shows a peak at 2θ of about 36° and does not show a peak 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 preferably made of silicon or a transition metal element other than the main component of the oxide semiconductor film. The elements that bond to oxygen stronger than the metal elements that form the oxide semiconductor film, such as Zn, By removing oxygen from the oxide semiconductor film, the atomic arrangement of the oxide semiconductor film is disturbed, and the crystallinity is reduced. In addition, heavy metals such as iron and nickel, argon, and carbon dioxide are Since the diameter (or molecular radius) of the ions is large, when the ions are contained inside the oxide semiconductor film, the oxide semiconductor film The impurities contained in the oxide semiconductor film are disturbed, which causes a decrease in crystallinity. Pure materials may act as carrier traps or carrier generation sources.

[0222] The CAAC-OS film is an oxide semiconductor film with a low density of defect states. Oxygen vacancies in semiconductor films 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 carrier generation source, the carrier density can be reduced. The transistor using the oxide semiconductor film has electrical characteristics (noise) in which the threshold voltage is negative. It is also called "marine". It is rare for it to become "high purity genuine" or "substantially high purity". The intrinsic oxide semiconductor film has few carrier traps. Transistors using the film have little fluctuation in electrical characteristics and are highly reliable. Note that it takes a certain time for 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 were a fixed charge. In addition, a transistor using an oxide semiconductor film having a high density of defect states has unstable electrical characteristics. There may be cases where this occurs.

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

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

[0226] In the TEM image of the microcrystalline oxide semiconductor film, crystal parts can be clearly seen. 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 to 3 nm or less. The oxide semiconductor film having nc-OS (nanocrystalline O The nc-OS film is called a T In EM images, 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 analysis 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 out-of-plane method, the crystal planes are In addition, the peaks shown in the figure are not detected in the nc-OS film because the probe diameter is larger than that in the crystalline region. Electron beam diffraction (also called selected area electron beam diffraction) using an electron beam of 50 nm or more (for example) 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 to 30 nm). When electron beam diffraction (also called nanobeam electron beam diffraction) is performed using the electron beam shown below, In addition, when the nc-OS film was subjected to nanobeam electron diffraction, a circular pattern was observed. In addition, for the nc-OS film, a bright area (ring-shaped) may be observed. 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 that has 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, the crystal orientation is not regular 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 AAC-OS films.

[0230] The oxide semiconductor film included in the transistor and the capacitor of the semiconductor device of one embodiment of the present invention is In addition, an oxide semiconductor film having a stacked structure may be used. In the case where 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 functioning as an electrode of a capacitor is preferably a Since the impurity concentration in the insulating 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. In the following description, the same reference numerals will be used to designate parts having the same functions as those in the first embodiment. and their detailed explanation 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 ( 303) and a circuit having a function of protecting the element (hereinafter, referred to as a protection circuit 304). 6) and a terminal portion 307. Note that the protection circuit 306 is not provided in the configuration. This is also 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 the whole of the pixel portion 302 is not formed on the same substrate, the driving circuit A part or the whole of the path portion 304 is made of COG (Chip On Glass) or TAB (T This can be implemented using the ape 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 includes a circuit for driving a plurality of display elements (hereinafter referred to as pixel circuit 301), and a driving circuit The path section 304 is a circuit (hereinafter, a gate driver) that outputs a signal (scanning signal) for selecting a pixel. 304a) to supply signals (data signals) for driving the display elements of the pixels. The pixel circuit 304 includes a driver circuit such as a 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 input via the terminal unit 307, and a signal is output via the terminal unit 307. For example, the gate driver 304a receives a start pulse signal, a clock signal, etc. The gate driver 304a 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 scanning lines GL_1 to Alternatively, the gate driver 304a may control the GL_X by dividing it. However, the gate driver 30 has a function of supplying 4a may also provide another signal.

[0237] The source driver 304b includes a shift register and the like. Through the terminal section 307, a signal for driving the shift register as well as a source of a data signal are transmitted. The source driver 304b receives a signal (image signal) that is to be displayed on the pixel circuit based on the image signal. The source driver 304b has a function of generating a data signal to be written to the pixel 301. A data signal is generated according to 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 line 101 through the data line 102. 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 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 number of analog switches, The image signal can be time-division-multiplexed and output as a data signal. Also, a shift register, etc. This may be used to configure the source driver 304b.

[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 inputted through the data line DL, and a data signal is given through one of the data lines DL. A data signal is input to each of the pixel circuits 301. 304a controls writing and holding of data of the data signal. For example, The second pixel circuit 301 is connected to a gate driver GL_m (where m is a natural number equal to or smaller than X) via a scanning line GL_m. A pulse signal is input from 304a, and the data line DL_n ( A data signal is input from the source driver 304b via a transistor (n is a natural number equal to or smaller 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 a wiring between the gate driver 304a and the terminal unit 307. Alternatively, the protection circuit 306 may be a wiring between the source driver 304b and the terminal unit 307. The terminal unit 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 provided with terminals for inputting control signals and image signals.

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

[0242] As shown in FIG. 12A, a protection circuit 30 is provided in each of a pixel section 302 and a driver circuit section 304. 6, ESD (Electro Static Discharge: This can improve the resistance of the display device to overcurrent caused by electrostatic discharge (ESD) 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 protection circuit 306 is connected to the source driver 304b Alternatively, a protection circuit 306 may be connected to the terminal portion 307. It can also be written as:

[0243] In FIG. 12A, the gate driver 304a and the source driver 304b Therefore, although an example in which the driver 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 is formed separately. A substrate (for example, a drive circuit substrate formed of a single crystal semiconductor film or a polycrystalline semiconductor film) is It may also be configured to be equipped with

[0244] In addition, the pixel circuits 301 shown in FIG. 12A may have a configuration shown in FIG. 12B. 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 appropriately set according to the specifications of the pixel circuit 301. The alignment state of the liquid crystal element 370 is set by the written data. A common potential is applied to one of a pair of electrodes of the liquid crystal element 370 of 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. A different potential may be applied to one of the electrodes.

[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 M icro-cell mode, OCB (Optically Compensated Birefringence mode, FLC (Ferroelectric Liquid 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, etc. may also be used. In addition to the above-mentioned driving method, the display device can be driven by an ECB (Electric Carrier Bipolar Transistor) or the like. Ally Controlled Birefringence mode, PDLC(P Oligomeric Dispersed Liquid Crystal (PNLC) mode (Polymer Network Liquid Crystal) mode, guest hole However, there are various types of liquid crystal elements and their driving methods, and they are not limited to these. A variety of different types of sensors 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 liquid crystal that exhibits the blue phase. In addition, since liquid crystals that exhibit a blue phase are optically isotropic, no alignment treatment is required. In addition, the viewing angle dependency is small.

[0249] In the pixel circuit 301 in the mth row and the nth column, One of the electrodes is electrically connected to the data line DL_n, and the other is 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 is electrically connected to the on-state or the off-state. Thus, the write control circuit 100 has a function of controlling the writing of data of the data signal.

[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. The pixel circuits 301 in each row are selected in sequence by a, and the transistors 150 are turned on to output data. Write the data of the data signal.

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

[0253] Although the liquid crystal element 370 is used as the display element in the above embodiment of the present invention, 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 A light-emitting device, which is a device having an element and a light-emitting element, can be used in various forms or can be used in various forms. As an example of a display element, a display device, a light-emitting element, or a light-emitting device, EL (electroluminescence) elements (EL elements including organic and inorganic materials, organic EL LED elements, inorganic EL elements), LEDs (white LEDs, red LEDs, green LEDs, blue LEDs, etc. etc.), transistors (transistors that emit light according to current), electron emission 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 that uses this technology is a field emission display (FED) or SE. D-type flat panel display (SED: Surface-conduction Electro Display devices using liquid crystal elements include One example is a liquid crystal display (transmissive liquid crystal display, semi-transmissive liquid crystal display). , reflective LCDs, direct-view LCDs, projection LCDs, etc. An example of a display device using electronic ink or electrophoretic elements is electronic paper. There is.

[0255] An example in which a liquid crystal element is used as a display element is shown in FIG. Between the common electrode 124 and the conductive film 120, a liquid crystal layer 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 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 described with reference to FIG. 13 and FIG.

[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, 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 appropriate to match the size of 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 the display panel 006 to make it into an optical touch panel.

[0263] The backlight unit 8007 includes a light source 8008. Alternatively, a light diffusing plate may be used in the configuration in which the light diffusing plate is provided at the end of the light unit 8007.

[0264] The frame 8009 protects the display panel 8006 and also supports 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 frame. 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 be added.

[0267] 14(A) to 14(H) are diagrams showing electronic devices. These electronic devices are A body 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, and an 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, etc.) can.

[0268] FIG. 14A shows a mobile computer, which includes, in addition to the above, a switch 5009. , an infrared port 5010, etc. FIG. 14(B) shows a mobile phone equipped with a recording medium. A portable image reproducing device (e.g., a DVD reproducing device) and, in addition to the above, the following devices are also included: The display unit 5002, the recording medium reading unit 5011, etc. In addition to the above, the display includes a second display unit 5002 and a support unit 5012. , earphones 5013, etc. FIG. 14(D) shows a portable game machine. In addition to the above, the recording medium reading unit 5011 and the like can be included. FIG. 14(E) shows This is a digital camera with a television 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. This is a slot 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, The portable television receiver may include a tuner, an image processor, etc. In addition to the above, the device includes a charger 5017 capable of transmitting and receiving signals. can be done.

[0269] The electronic devices illustrated in FIGS. 14A to 14H can have various functions. For example, the function to display various information (still images, videos, text images, etc.) on the display, Panel function, calendar, date or time display function, various software (platform A function to control processing by a program, a wireless communication function, and a function to control various Functions for connecting to computer networks, wireless communication functions for transmitting various data, 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 the other display section is used mainly to display text information. A function to display images with parallax taken into account on multiple displays to create a stereoscopic effect. Furthermore, in electronic devices having an image receiving unit, These include functions for taking still images, taking videos, and automatically or manually correcting the images. The camera has a function to correct the captured image, a function to save the captured image on a recording medium (external or built-in to the camera), The image displayed on the display unit can have a function of displaying the image. The functions that the electronic device shown in 4(H) can have are not limited to these, and various functions may be included. It is possible to have.

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

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

[0272] 102 Substrate 102a Substrate 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 Transistor 152 Transistor 160 Capacitive element 161 Capacitive element 162 Capacitive 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 Capacitive element 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 element 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 cabinet 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 and a capacitor, a first conductive film having a function 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 located above the first insulating film and having a channel formation region of the transistor; a second oxide semiconductor film having a region located above the first insulating film and functioning as the other electrode of the capacitor; a second conductive film having a region located above the first oxide semiconductor film and electrically connected to the first oxide semiconductor film; a third conductive film having a region located 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; 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; Semiconductor device.

2. A semiconductor device including a pixel including a transistor and a capacitor, a first conductive film having a function 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 located above the first insulating film and having a channel formation region of the transistor; a second oxide semiconductor film having a region located above the first insulating film and functioning as the other electrode of the capacitor; a second conductive film having a region located above the first oxide semiconductor film and electrically connected to the first oxide semiconductor film; a third conductive film having a region located 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; 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; Semiconductor device.

3. A semiconductor device including a pixel including a transistor and a capacitor, a first conductive film having a function 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 located above the first insulating film and having a channel formation region of the transistor; a second oxide semiconductor film having a region located above the first insulating film and functioning as the other electrode of the capacitor; a second conductive film having a region located above the first oxide semiconductor film and electrically connected to the first oxide semiconductor film; a third conductive film having a region located 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; the first insulating film includes a first layer including nitrogen and silicon, and a second layer including oxygen and silicon and having a region disposed above the first layer; 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; Semiconductor device.

4. A semiconductor device including a pixel including a transistor and a capacitor, a first conductive film having a function 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 located above the first insulating film and having a channel formation region of the transistor; a second oxide semiconductor film having a region located above the first insulating film and functioning as the other electrode of the capacitor; a second conductive film having a region located above the first oxide semiconductor film and electrically connected to the first oxide semiconductor film; a third conductive film having a region located 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; 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 including nitrogen and silicon, and a second layer including oxygen and silicon and having a region disposed above the first layer; 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; 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