Semiconductor device

Abstract

To provide a semiconductor device with a novel structure.SOLUTION: A semiconductor device includes: a silicon substrate; and a device provided above the silicon substrate. The device includes: a transistor; and a conductor. The transistor includes a metal oxide to a channel formation region. A conductivity is applied to the silicon substrate. The conductor is electrically connected to a drain of the transistor and the silicon substrate via an open part provided to the device. A heat radiation of the drain of the transistor can be effectively performed via the silicon substrate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One embodiment of the present invention relates to a semiconductor device. [Background technology]

[0002] As a new semiconductor, attention is being focused on metal oxides that exhibit semiconductor properties, known as oxide semiconductors. Development of transistors using oxide semiconductors is progressing day by day. For example, the following Patent Document 1 discloses the configuration of a DC-DC converter in which a transistor using the oxide semiconductor can be applied to a power transistor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2011 / 0254523 Summary of the Invention [Problem to be solved by the invention]

[0004] Oxide semiconductors such as In-Ga-Zn oxide (also written as IGZO) have a thermal conductivity that is about 1 / 100 that of insulating layers such as silicon oxide. Therefore, when a transistor is operating, heat generated by self-heating when a large current flows between the source and drain of the transistor tends to accumulate. Self-heating can cause fluctuations in the transistor's electrical characteristics or element degradation, leading to reduced reliability.

[0005] An object of one embodiment of the present invention is to provide a semiconductor device or the like having a novel structure.An object of one embodiment of the present invention is to provide a semiconductor device or the like having a novel structure with high reliability.An object of one embodiment of the present invention is to provide a semiconductor device or the like having a novel structure that can reduce the influence of a change in electrical characteristics of a transistor caused by self-heating or element deterioration.

[0006] The problems of one embodiment of the present invention are not limited to the problems listed above. The problems listed above do not preclude the existence of other problems. The other problems are problems not mentioned in this section, which will be described below. Problems not mentioned in this section can be derived by a person skilled in the art from the description in the specification or drawings, and can be appropriately extracted from these descriptions. One embodiment of the present invention solves at least one of the problems listed above and / or other problems. [Means for solving the problem]

[0007] One embodiment of the present invention is a semiconductor device including a silicon substrate and a device provided above the silicon substrate, the device including a transistor and a conductor, the transistor including a metal oxide in a channel formation region, the silicon substrate being conductive, and the conductor being electrically connected to a drain of the transistor and the silicon substrate through an opening provided in the device.

[0008] One embodiment of the present invention is a semiconductor device having a silicon substrate, a device provided above the silicon substrate, a first extraction electrode, and a second extraction electrode, the device having a transistor and a conductor, the transistor having a metal oxide in a channel formation region, the silicon substrate being made conductive, the conductor being electrically connected to each of the drain of the transistor and the silicon substrate through an opening provided in the device, the first extraction electrode being electrically connected to the conductor connected to the source of the transistor, and the second extraction electrode being electrically connected to the silicon substrate.

[0009] In one aspect of the present invention, the semiconductor device is preferably one in which the first extension electrode is electrically connected, via a metal wiring, to a conductor that is connected to the source of the transistor.

[0010] In one embodiment of the present invention, the semiconductor device is preferably one in which the second extraction electrode is directly connected to the silicon substrate.

[0011] In one embodiment of the present invention, the semiconductor device is preferably a semiconductor device in which the silicon substrate is imparted with p-type conductivity.

[0012] In one aspect of the present invention, the semiconductor device is preferably one in which the silicon substrate and the device are covered with a resin layer, and the resin layer is provided inside a housing.

[0013] In one aspect of the present invention, the semiconductor device is preferably a semiconductor device in which a heat sink is provided on the silicon substrate via an insulating layer.

[0014] Other aspects of the present invention will be described in the following embodiment and in the drawings. Effect of the Invention

[0015] One embodiment of the present invention can provide a semiconductor device or the like having a novel structure. Alternatively, one embodiment of the present invention can provide a semiconductor device or the like having a novel structure with high reliability. Alternatively, one embodiment of the present invention can provide a semiconductor device or the like having a novel structure in which the influence of fluctuation in electrical characteristics of a transistor due to self-heating or deterioration of an element can be reduced.

[0016] The effects of one embodiment of the present invention are not limited to the effects listed above. The effects listed above do not preclude the existence of other effects. The other effects are described below and are not mentioned in this section. The effects not mentioned in this section can be derived by a person skilled in the art from the description in the specification or drawings, and can be appropriately extracted from these descriptions. One embodiment of the present invention has at least one of the effects listed above and / or other effects. Therefore, one embodiment of the present invention may not have the effects listed above in some cases. [Brief description of the drawings]

[0017] [Figure 1] 1A and 1B are a perspective view and a schematic cross-sectional view illustrating one embodiment of the present invention. [Diagram 2] 2A, 2B, and 2C are top views illustrating one embodiment of the present invention. [Diagram 3] 3A and 3B are a perspective view and a circuit diagram illustrating one embodiment of the present invention. [Figure 4] 4A and 4B are schematic cross-sectional views illustrating one embodiment of the present invention. [Diagram 5] 5A, 5B, and 5C are schematic cross-sectional views illustrating one embodiment of the present invention. [Figure 6] 6A, 6B, and 6C are schematic cross-sectional views illustrating one embodiment of the present invention. [Figure 7] FIG. 7 is a schematic cross-sectional view illustrating one embodiment of the present invention. [Figure 8] 8A, 8B, 8C, and 8D are top views illustrating one embodiment of the present invention. [Figure 9] 9A, 9B, and 9C are circuit diagrams, graphs, and block diagrams illustrating one embodiment of the present invention. [Figure 10] FIG. 10 is a schematic cross-sectional view illustrating one embodiment of the present invention. [Figure 11] 11A and 11B are schematic cross-sectional views illustrating one embodiment of the present invention. [Figure 12] 12A and 12B are schematic cross-sectional views illustrating one embodiment of the present invention. [Figure 13] 13A and 13B are schematic cross-sectional views illustrating one embodiment of the present invention. [Figure 14] FIG. 14 is a diagram showing an electronic device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The following describes an embodiment of the present invention. However, one embodiment of the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that the embodiment and details can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, one embodiment of the present invention should not be interpreted as being limited to the description of the embodiment shown below.

[0019] In this specification, the ordinal numbers "first," "second," and "third" are used to avoid confusion of components. Therefore, they do not limit the number of components. Furthermore, they do not limit the order of the components. For example, a component referred to as "first" in one embodiment of this specification may be a component referred to as "second" in another embodiment or in the claims. For example, a component referred to as "first" in one embodiment of this specification may be omitted in another embodiment or in the claims.

[0020] In the drawings, the same elements or elements having similar functions, elements made of the same material, or elements formed at the same time may be given the same reference numerals, and repeated description thereof may be omitted.

[0021] In this specification, for example, the power supply potential VDD may be abbreviated to potential VDD, VDD, etc. This also applies to other components (for example, signals, voltages, circuits, elements, electrodes, wiring, etc.).

[0022] Furthermore, when the same reference symbol is used for multiple elements, particularly when it is necessary to distinguish between them, identification symbols such as “_1”, “_2”, "[n]”, "[m,n]”, etc. may be added to the reference symbol. For example, the second wiring GL is written as wiring GL[2].

[0023] (Embodiment 1) A structural example of a semiconductor device according to one embodiment of the present invention will be described with reference to FIGS.

[0024] The semiconductor device in this embodiment is a device including a power transistor (also called a power semiconductor) designed to pass a large current to a load. The power transistor is a transistor that handles a much larger amount of power than a display device, a logic circuit, or the like, because the amount of current flowing between an electrode connected to a source and an electrode connected to a drain and the voltage applied thereto are large.

[0025] 1A shows a perspective view of a semiconductor device 10 having a device 11 (sometimes called an element layer) provided on a silicon substrate 12. The device 11 has a plurality of transistors 23A to 23D, conductors 21A, 21B, and conductors 22A, 22B. The device 11 also has a plurality of openings 24A, 24B that reach the silicon substrate 12.

[0026] The conductors 21A and 21B function as electrodes connected to the sources of the transistors 23A to 23D. In the drawing, the conductors 21A and 21B are indicated with an "S" indicating the source side. In the configuration shown in FIG. 1A, two electrodes are shown connected to the source, but there may be one or three or more electrodes connected to the source.

[0027] The conductors 22A and 22B function as electrodes connected to the drains of the transistors 23A to 23D. In the drawing, the conductors 22A and 22B are illustrated with a "D" indicating the drain side. Note that in the configuration shown in FIG. 1A, two electrodes are illustrated as being connected to the drain, but there may be one or three or more electrodes connected to the drain.

[0028] Although not shown in FIG. 1A, the transistors 23A to 23D each have a region that functions as a gate, a channel forming region, a drain, or a source. The transistor 23A is a transistor provided between the conductor 21A connected to the source and the conductor 22A connected to the drain. The transistor 23B is a transistor provided between the conductor 21A connected to the source and the conductor 22B connected to the drain. The transistor 23C is a transistor provided between the conductor 21B connected to the source and the conductor 22A connected to the drain. The transistor 23D is a transistor provided between the conductor 21B connected to the source and the conductor 22B connected to the drain.

[0029] The transistors 23A to 23D are arranged between the conductors 21A, 21B and the conductors 22A, 22B such that the sources and drains of the multiple transistors are in parallel. By arranging multiple transistors in parallel, a large current can be passed between the conductors 21A, 21B and the conductors 22A, 22B. In addition, the transistors 23A to 23D can be configured using miniaturized transistors with a channel length of 1 μm or less, thereby reducing variations in transistor characteristics.

[0030] The transistors 23A to 23D are transistors (referred to as OS transistors) in which a semiconductor layer having a channel formation region is formed using an oxide semiconductor. Note that an oxide semiconductor may be called a metal oxide or an oxide. Note that the OS transistors will be described as n-channel transistors unless otherwise specified. By reducing the carrier concentration of the oxide semiconductor, the current that flows between the source and drain when the oxide semiconductor is off (also referred to as off-current or leakage current) can be made extremely low. Details of OS transistors will be described later.

[0031] OS transistors can be easily integrated because they can be freely arranged by stacking them on a silicon substrate, etc. In addition, OS transistors can be manufactured at low cost because they can be manufactured using the same manufacturing equipment as transistors whose semiconductor layer having a channel formation region is made of silicon (Si transistors).

[0032] Furthermore, if an OS transistor includes a back gate electrode in addition to a gate electrode, a source electrode, and a drain electrode, it can be a four-terminal semiconductor element. It can be configured as an electric circuit network that can independently control the input and output of signals flowing between the source and drain according to the voltage applied to the gate electrode or the back gate electrode. Therefore, the circuit can be designed with the same concept as that of an LSI. In addition, OS transistors have better electric characteristics than Si transistors in high-temperature environments. Specifically, the ratio of on-current to off-current is large even at high temperatures of 100°C to 200°C, preferably 125°C to 150°C, so that good switching operation can be performed.

[0033] The silicon substrate 12 is a silicon substrate to which electrical conductivity has been imparted. The silicon substrate 12 is a silicon substrate to which an impurity element has been introduced to impart n-type or p-type electrical conductivity. By making the silicon substrate 12 a silicon substrate to which a p-type electrical conductivity has been imparted, the thermal conductivity can be increased compared to a silicon substrate to which an n-type electrical conductivity has been imparted. The silicon substrate 12 may be configured to have a transistor for forming a logic circuit.

[0034] The conductors are provided in the openings 24A and 24B, thereby connecting the conductors 22A and 22B to the silicon substrate 12. That is, the drains of the transistors 23A to 23D are connected to the silicon substrate 12 via the conductors 22A and 22B and the conductors provided in the openings 24A and 24B. The drains of the transistors 23A to 23D may be connected to the silicon substrate 12 via the conductors 22A and 22B, or may be directly connected to each other via the conductors provided in the openings 24A and 24B.

[0035] 1A can be configured to dissipate heat generated on the drain side due to current flowing through OS transistors 23A to 23D to silicon substrate 12 via a conductor in an opening provided in device 11. This can suppress fluctuations in the electrical characteristics of transistors 23A to 23D or element degradation due to heat generation, resulting in a highly reliable semiconductor device 10.

[0036] Fig. 1B is a schematic cross-sectional view of the semiconductor device 10 taken along the cut plane AB in Fig. 1A. In the schematic cross-sectional view shown in Fig. 1B, a device 11 is provided on a silicon substrate 12, as in Fig. 1A. The device 11 is provided with transistors 23A and 23B. The transistor 23A has a gate electrode 26A and an oxide layer 25A functioning as a semiconductor layer. The transistor 23B has a gate electrode 26B and an oxide layer 25B functioning as a semiconductor layer. Note that the oxide layer 25A and the oxide layer 25B may be referred to as an oxide layer 28 in other drawings.

[0037] In the transistor 23A, the oxide layer 25A is connected to the conductor 21A. The oxide layer 25A is also connected to the conductor 22A. The current flowing through the transistor 23A flows from the drain (D) side to the source (S) side (indicated by the thin arrow in the figure). Therefore, in the oxide layer 25A, electrons are accelerated in the drain side region 27A, causing self-heating. The heat-generating region 27A dissipates heat to the silicon substrate 12 side via the conductor 22A and the conductor provided in the opening 24A (indicated by the thick dotted arrow in the figure).

[0038] In the transistor 23B, the oxide layer 25B is connected to the conductor 21A. The oxide layer 25B is also connected to the conductor 22B. The current flowing through the transistor 23B flows from the drain (D) side to the source (S) side (indicated by the thin arrow in the figure). Therefore, in the oxide layer 25B, electrons are accelerated in the drain side region 27B, causing self-heating. The heat-generating region 27B dissipates heat to the silicon substrate 12 side via the conductor 22B and the conductor provided in the opening 24B (indicated by the thick dotted arrow in the figure).

[0039] The transistors 23C and 23D have the same configuration as the transistors 23A and 23B. Therefore, heat generated on the drain side of the transistor can be dissipated to the silicon substrate 12 via the conductors 22A and 22B and the conductors provided in the openings 24A and 24B.

[0040] 1A and 1B, in the structure of a semiconductor device according to one embodiment of the present invention, a silicon substrate and an OS transistor are stacked, and heat generated on the drain side of the transistor is dissipated to the silicon substrate side through a conductor provided in an opening. The silicon substrate can function as a heat sink. Fluctuations in the electrical characteristics of the transistor or element deterioration due to heat generation can be suppressed, and a highly reliable semiconductor device can be obtained.

[0041] Next, Fig. 2A shows a top view for explaining the configuration of the device 11 described in Fig. 1A and Fig. 1B. In the top view of Fig. 2A, transistors 23A to 23D for controlling the electrical connection between the conductors 21A, 21B and the conductors 22A, 22B are illustrated as X-shaped regions. Also, openings 24A, 24B in which conductors for connecting the drains of the transistors 23A to 23D to the silicon substrate 12 (not shown) are provided can be provided in regions overlapping with the conductors 22A, 22B. Note that the conductors 21A, 21B and the conductors 22A, 22B illustrated in the top layout diagram can function as electrodes for connecting wiring to the outside.

[0042] The shape of the conductors 21A, 21B and conductors 22A, 22B functioning as electrodes as viewed from above is preferably such that the distance from the external connection wiring to each transistor is equal. For example, it is preferable to have a circular shape or a triangular shape as shown in Fig. 2A. With this configuration, it is possible to equalize the wiring resistance from the wiring connected to the conductors 21A, 21B and conductors 22A, 22B by wire bonding or the like to the multiple transistors.

[0043] Fig. 2B shows an enlarged top view of the region in which the transistor 23B shown in Fig. 2A is provided. In Fig. 2B, a plurality of island-shaped oxide layers 28 are provided between comb-shaped electrodes extending from the conductor 21A and the conductor 22B. The transistor 23B shown in Fig. 2A can be represented as transistors 23B_1 and 23B_2 provided at both ends of the conductor 22B.

[0044] In Fig. 2C, the electrodes represented by conductor 21A and conductor 22B are shown by dotted lines. Fig. 2C also shows conductors 26B_1 and 26B_2 functioning as gate electrodes superimposed on island-shaped oxide layer 28, and conductor 29 functioning as a backgate electrode.

[0045] 3A shows a perspective view of the transistor 23B (a transistor applicable to the transistors 23A to 23D is also referred to as a transistor 23) in the X direction and the Y direction shown in FIG. 2C. FIG. 3A shows the conductor 26B_1 and the conductor 29 provided so as to overlap the island-shaped oxide layer 28. FIG. 3A shows the conductor 29 as a back gate electrode and an electrode BGE. FIG. 3A shows the conductor 26B_1 as a top gate electrode and an electrode TGE. FIG. 3A shows one of the island-shaped oxide layer 28 separated by the conductor 26B_1 and the conductor 29 as a terminal "S" and the other as a terminal "D". The transistor 23 shown in FIG. 3A can be represented by the symbol shown in FIG. 3B. Note that the configuration of the transistor will be described in detail in the second embodiment.

[0046] Next, with reference to FIGS. 4A, 4B, and 5A to 5C, modifications of the schematic cross-sectional view of the semiconductor device 10 described with reference to FIG. 1B will be described.

[0047] 1B, the semiconductor device 10A shown in Fig. 4A illustrates a configuration example in which an electrode for taking out the electric current to the outside or an electrode for connecting to an external metal wiring is disposed on the upper surface of the device 11. In the configuration example of Fig. 4A, the conductor 21A connected to the sources of the transistors 23A and 23B and the conductors 22A and 22B connected to the drains of the transistors 23A and 23B can be disposed on the same side, that is, the upper surface of the device 11.

[0048] In the semiconductor device 10B shown in FIG. 4B, an example of a configuration in which an external extraction electrode or an electrode connected to an external metal wiring is disposed on the upper surface of the device 11 is illustrated, which is different from the configuration in FIG. 4A. In the example of the configuration in FIG. 4B, the sources of the transistors 23A and 23B are connected to a conductor 31A provided on the electrode layer 30 in the upper layer of the device 11 via a conductor 21A connected thereto, and the drains of the transistors 23A and 23B are connected to a conductor 22A or 22B and a conductor 31B provided on the electrode layer 30 in the upper layer of the device 11 via a silicon substrate 12. In the semiconductor device 10B shown in FIG. 4B, electrodes can be disposed on the same surface, which is the upper surface of the device 11, as in FIG. 4A.

[0049] Unlike FIGS. 4A and 4B, the semiconductor device 10C shown in FIG. 5A illustrates a configuration example in which the silicon substrate 12 also functions as an electrode for taking out the external signal or an electrode for connecting to an external metal wiring. In the configuration example of FIG. 5A, the conductor 31A provided in the electrode layer 30 in the upper layer of the device 11 via the conductor 21A connected to the sources of the transistors 23A and 23B, and the silicon substrate 12 in the lower layer of the device 11 via the conductors 22A and 22B connected to the drains of the transistors 23A and 23B, can be arranged on different sides. By using the silicon substrate 12 side as an electrode, the area for bonding the external take-out electrode or the metal wiring to be wire-bonded can be increased, making it easier to make electrical connections.

[0050] In the semiconductor device 10D shown in Fig. 5B, as a configuration different from that in Fig. 5A, a conductor 31A provided in an electrode layer 30 in the upper layer of the device 11 via a conductor 21A connected to the sources of the transistors 23A and 23B, and conductors 22A and 22B in the lower layer of the oxide layer connected to the drains of the transistors 23A and 23B can be arranged on different sides of the silicon substrate 12. By using the silicon substrate 12 side as an electrode, it is possible to easily connect to an external extraction electrode or a metal wiring to be wire-bonded. In addition, by arranging the conductors 22A and 22B in the lower layer of the oxide layer, the path for heat dissipation can be shortened.

[0051] In the semiconductor device 10D shown in Fig. 5B, the silicon substrate 12 is illustrated as being connected to an external extraction electrode or metal wiring to be wire-bonded, but other configurations are also possible. For example, as in the semiconductor device 10E shown in Fig. 5C, electrodes can be arranged on the same side, that is, the upper surface of the device 11, via conductors 31A, 31B, etc. provided on the electrode layer 30. By adopting this configuration, in the configuration of Fig. 5B as well, electrodes can be arranged on the same side, that is, the upper surface of the device 11, as in Fig. 4A.

[0052] 6A to 6C are schematic cross-sectional views of an example of an electronic component when the semiconductor device 10 described above is installed in a housing. Note that an electronic component having the semiconductor device 10 installed in a housing may be called a semiconductor device because it is a device having transistors that utilize the semiconductor characteristics.

[0053] In the schematic cross-sectional view of electronic component 100A shown in Fig. 6A, semiconductor device 10, metal wiring 104A, 104B, extraction electrodes 105A, 105B, and resin layer 103 are included in housing 106. Semiconductor device 10 is fixed to substrate 101 by adhesive layer 102 within housing 106. Note that semiconductor device 10 shown in Fig. 6A is configured to be connected to the extraction electrodes on the top surface of device 11 shown in Figs. 4A and 4B. Substrate 101 and adhesive layer 102 are preferably made of a material with a higher thermal conductivity than the surrounding constituent materials in order to enhance the heat dissipation of the silicon substrate.

[0054] The semiconductor device 10 is covered with a resin layer 103 within a housing 106. The extraction electrode 105A is connected to an electrode on the top surface of a device included in the semiconductor device 10 via a metal wiring 104A. The extraction electrode 105B is connected to an electrode on the top surface of a device included in the semiconductor device 10 via a metal wiring 104B.

[0055] In the schematic cross-sectional view of electronic component 100B shown in Fig. 6B, semiconductor device 10, metal wiring 104A, extraction electrodes 105A and 105B, and resin layer 103 are disposed within housing 106. Semiconductor device 10 is fixed to substrate 101 within housing 106 by adhesive layer 102. Semiconductor device 10 shown in Fig. 6B is configured to be connected to the extraction electrodes on the top surface of device 11 and on the silicon substrate 12 side shown in Figs. 5A and 5B.

[0056] The semiconductor device 10 is covered with a resin layer 103 within a housing 106. The extraction electrode 105A is connected to an electrode on the top surface of a device of the semiconductor device 10 via a metal wiring 104A. The extraction electrode 105B is directly connected to a silicon substrate of the semiconductor device 10.

[0057] In the schematic cross-sectional view of electronic component 100C shown in Fig. 6C, semiconductor device 10, metal wiring 104A, extraction electrodes 105A and 105B, and resin layer 103 are disposed within housing 106. Semiconductor device 10 is fixed to substrate 101 within housing 106 by adhesive layer 102 via extraction electrode 105B. Semiconductor device 10 shown in Fig. 6C is configured to be connected to the extraction electrode on the top surface of device 11 and on the silicon substrate 12 side shown in Figs. 5A and 5B.

[0058] The semiconductor device 10 is covered with a resin layer 103 within a housing 106. The extraction electrode 105A is connected to an electrode on the top surface of a device of the semiconductor device 10 via a metal wiring 104A. The extraction electrode 105B is directly connected to a silicon substrate of the semiconductor device 10.

[0059] The electronic components 100A to 100C shown in Fig. 6A to 6C can be configured to be connected to a heat sink. Fig. 7 shows an electronic component 100D in which a heat sink 107 is provided on the substrate 101 side. This configuration can improve heat dissipation from the silicon substrate 12 side.

[0060] Next, in FIG. 8A to FIG. 8D, modifications of the top view of the device 11 described in FIG. 2A will be described.

[0061] In the device 11A shown in Fig. 8A, similar to Fig. 2A, conductors 21A, 21B, conductors 22A, 22B, and an X-shaped region 23R in which transistors 23A to 23D are provided are illustrated. In the device 11A shown in Fig. 8A, a configuration is illustrated in which the silicon substrate 12 and the drains of the transistors 23A to 23D are connected to each other through openings 24A, 24B that reach the silicon substrate 12 in regions overlapping with the conductors 22A, 22B that are connected to the drains of the transistors 23A to 23D.

[0062] In device 11B shown in Fig. 8B, conductors 21A and 21B, conductors 22A and 22B, and region 23R are illustrated. Device 11B shown in Fig. 8B is configured to include transistors provided on silicon substrate 12 in regions 51A and 51B of silicon substrate 12 that overlap conductors 21A and 21B connected to the sources of transistors 23A to 23D. With this configuration, a logic circuit can be configured at a position away from openings 24A and 24B through which self-generated drain heat is dissipated.

[0063] In the device 11C shown in FIG. 8C, conductors 21A, 21B, conductors 22A, 22B, and region 23R are illustrated. In the device 11C shown in FIG. 8C, a configuration is illustrated in which the silicon substrate 12 and the drains of transistors 23A to 23D are connected by openings 24C, 24D reaching the silicon substrate 12 in a region overlapping with region 23R. By adopting such a configuration, the heat generated by the drain can be dissipated, and the heat of the transistors can be made uniform to stabilize the transistor characteristics. Also, compared with a configuration in which wiring by conductors is routed to the silicon substrate 12, there are effects such as reducing the resistance of the wiring or being able to dissipate heat through a short path.

[0064] Also, as illustrated in the device 11D of FIG. 8D, a configuration can be adopted in which the configuration of the device 11A illustrated in FIG. 8A and the configuration of the device 11C illustrated in FIG. 8C are combined.

[0065] In FIGS. 9A to 9D, operation examples and application examples of the semiconductor device and the electronic component described above are shown.

[0066] FIG. 9A illustrates a state in which a current ID flows between the source (S) and the drain (D) when a voltage VG is applied to the gate of the transistor 23 included in the semiconductor device 20 and a voltage VBG is applied to the back gate.

[0067] FIG. 9B is a schematic diagram of a graph representing the current-voltage characteristics of the transistor 23 illustrated in FIG. 9A. By switching the back gate voltage between voltages VBG_A and VBG_B (<VBG_A), states with different electrical characteristics can be switched. For example, when the back gate voltage is the voltage VBG_A, the amount of current flowing between the source (S) and the drain (D) when the transistor 23 is on is increased, and when the back gate voltage is the voltage VBG_B, the amount of current flowing between the source (S) and the drain (D) when the transistor 23 is off is made extremely low.

[0068] By configuring transistor 23 of semiconductor device 10 that functions as a power transistor with an OS transistor, it is also possible to configure semiconductor device 10 within a battery protection circuit 60, such as a power storage device 199 including a battery 61 as shown in Figure 9C.

[0069] As described above, in the structure of the semiconductor device according to one embodiment of the present invention, a silicon substrate and an OS transistor are stacked, and heat generated on the drain side of the transistor can be dissipated to the silicon substrate through an opening. In other words, the silicon substrate can function as a heat sink. Therefore, a change in the electrical characteristics of the transistor or element deterioration due to heat generation can be suppressed, and a highly reliable semiconductor device can be obtained.

[0070] (Embodiment 2) In this embodiment mode, a cross-sectional structure example of the semiconductor device described in the above embodiment mode will be described with reference to the drawings.

[0071] The semiconductor device shown in Fig. 10 has a transistor 23 of a device 11 provided on a silicon substrate 12. The semiconductor device shown in Fig. 10 also shows a conductor 21 connected to the source of the transistor 23 and a conductor 22 connected to the drain. The semiconductor device shown in Fig. 10 also shows an opening 24 extending from the conductor 22 to the silicon substrate 12, and the opening 24 corresponds to the openings 24A and 24B described in the first embodiment. Fig. 11A is a cross-sectional view of the transistor 23 in the channel length direction, and Fig. 11B is a cross-sectional view of the transistor 23 in the channel width direction.

[0072] The transistor 23 is an OS transistor corresponding to the transistors 23A to 23D described in Embodiment 1. The off-state current of the transistor 23 is small, so that the power consumption of an electronic device including the semiconductor device can be reduced.

[0073] The silicon substrate 12 is a substrate imparted with p-type conductivity by introducing boron or the like to enhance thermal conductivity. By forming a silicon substrate imparted with p-type conductivity, it is possible to improve thermal conductivity compared to a silicon substrate imparted with n-type conductivity or a silicon substrate not imparted with conductivity. The silicon substrate may be a substrate imparted with n-type conductivity by arsenic, phosphorus, or the like. The silicon substrate 12 may be configured to include p-channel or n-channel transistors.

[0074] On the silicon substrate 12, an insulator 320, an insulator 322, an insulator 324, and an insulator 326 are stacked in this order.

[0075] As the insulators 320, 322, 324, and 326, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum nitride oxide, aluminum nitride, or the like can be used.

[0076] In this specification, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen, aluminum oxynitride refers to a material whose composition contains more oxygen than nitrogen, and aluminum nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0077] The insulator 322 may function as a planarizing film that planarizes steps of the silicon substrate 12 provided thereunder. For example, the upper surface of the insulator 322 may be planarized by a planarization process using a chemical mechanical polishing (CMP) method or the like to enhance flatness.

[0078] The insulator 324 is preferably a film having a barrier property that prevents hydrogen or impurities from diffusing from the silicon substrate 12 or the like to a region where the transistor 23 is provided.

[0079] As an example of a film having a barrier property against hydrogen, for example, silicon nitride formed by a CVD method can be used. Here, hydrogen diffusion into a semiconductor element having an oxide semiconductor such as the transistor 23 may deteriorate the characteristics of the semiconductor element. Therefore, it is preferable to use a film that suppresses hydrogen diffusion between the transistor 23 and the silicon substrate 12. Specifically, the film that suppresses hydrogen diffusion is a film that releases a small amount of hydrogen.

[0080] The amount of desorption of hydrogen can be analyzed, for example, by using thermal desorption spectrometry (TDS) etc. For example, the amount of desorption of hydrogen from the insulator 324 is calculated as 10×10 per area of ​​the insulator 324 when the surface temperature of the film is in the range of 50° C. to 500° C. in the TDS analysis. 15 atoms / cm 2 Less than or equal to 5×10 15 atoms / cm 2 The following is acceptable.

[0081] The insulator 326 preferably has a lower dielectric constant than the insulator 324. For example, the relative dielectric constant of the insulator 326 is preferably less than 4, and more preferably less than 3. For example, the relative dielectric constant of the insulator 326 is preferably 0.7 times or less, and more preferably 0.6 times or less, the relative dielectric constant of the insulator 324. By using a material with a low dielectric constant as the interlayer film, the parasitic capacitance generated between wirings can be reduced.

[0082] Conductors 328 and 330 that connect the silicon substrate 12 and the transistor 23 are embedded in the insulators 320, 322, 324, and 326. The conductors 328 and 330 function as plugs or wiring. A plurality of structures of conductors that function as plugs or wiring may be collectively given the same reference numeral. In this specification, the wiring and the plug that connects to the wiring may be integral. That is, a part of the conductor may function as the wiring, and a part of the conductor may function as the plug.

[0083] As the material for each plug and wiring (conductor 328, conductor 330, etc.), a conductive material such as a metal material, an alloy material, a metal nitride material, or a metal oxide material can be used in a single layer or a laminated layer. It is preferable to use a high melting point material such as tungsten or molybdenum that has both heat resistance and conductivity, and it is preferable to use tungsten. Alternatively, it is preferable to form the wiring from a low resistance conductive material such as aluminum or copper. By using a low resistance conductive material, it is possible to reduce the wiring resistance.

[0084] A wiring layer may be provided over the insulator 326 and the conductor 330. For example, in FIG. 10, an insulator 350, an insulator 352, and an insulator 354 are stacked in this order. A conductor 356 is formed in the insulator 350, the insulator 352, and the insulator 354. The conductor 356 functions as a plug or wiring that connects the silicon substrate 12 and the transistor 23. Note that the conductor 356 can be provided using a material similar to that of the conductor 328 or the conductor 330.

[0085] For example, the insulator 350 is preferably an insulator having a barrier property against hydrogen, similar to the insulator 324. The conductor 356 preferably includes a conductor having a barrier property against hydrogen. In particular, a conductor having a barrier property against hydrogen is formed in an opening provided in the insulator 350 having a barrier property against hydrogen. With this configuration, the silicon substrate 12 and the transistor 23 can be separated by a barrier layer, and diffusion of hydrogen from the silicon substrate 12 to the transistor 23 can be suppressed.

[0086] As the conductor having a barrier property against hydrogen, for example, tantalum nitride or the like may be used. Also, by stacking tantalum nitride and highly conductive tungsten, it is possible to suppress the diffusion of hydrogen from the silicon substrate 12 while maintaining the conductivity of the wiring. In this case, it is preferable that the tantalum nitride layer having a barrier property against hydrogen be in contact with the insulator 350 having a barrier property against hydrogen.

[0087] An insulator 510, an insulator 512, an insulator 514, and an insulator 516 are stacked in this order over the insulator 354. Any of the insulator 510, the insulator 512, the insulator 514, and the insulator 516 is preferably made of a substance that has a barrier property against oxygen or hydrogen.

[0088] For example, the insulator 510 and the insulator 514 are preferably made of a film having a barrier property that prevents hydrogen or impurities from diffusing from the silicon substrate 12 or the like to a region where the transistor 23 is provided. Therefore, it is preferable to use a material similar to that of the insulator 324.

[0089] Silicon nitride formed by CVD can be used as an example of a film having a barrier property against hydrogen. Here, hydrogen diffusion into a semiconductor element having an oxide semiconductor such as the transistor 23 may deteriorate the characteristics of the semiconductor element. Therefore, it is preferable to use a film that suppresses hydrogen diffusion between the silicon substrate 12 and the transistor 23. Specifically, the film that suppresses hydrogen diffusion is a film that releases a small amount of hydrogen.

[0090] As a film having a barrier property against hydrogen, for example, the insulator 510 and the insulator 514 are preferably made of a metal oxide such as aluminum oxide, hafnium oxide, or tantalum oxide.

[0091] In particular, aluminum oxide has a high blocking effect of preventing the film from permeating both oxygen and impurities such as hydrogen and moisture that cause fluctuations in the electrical characteristics of a transistor. Therefore, aluminum oxide can prevent impurities such as hydrogen and moisture from entering the transistor 23 during and after the transistor manufacturing process. In addition, aluminum oxide can suppress the release of oxygen from the metal oxide that constitutes the transistor 23. Therefore, aluminum oxide is suitable for use as a protective film for the transistor 23.

[0092] For example, the insulator 512 and the insulator 516 can be formed using a material similar to that of the insulator 320. By using a material with a relatively low dielectric constant for these insulators, parasitic capacitance between wirings can be reduced. For example, the insulators 512 and the insulator 516 can be formed using a silicon oxide film, a silicon oxynitride film, or the like.

[0093] A conductor 518 and a conductor constituting the transistor 23 (for example, the conductor 503) are embedded in the insulator 510, the insulator 512, the insulator 514, and the insulator 516. The conductor 518 functions as a plug or wiring that connects the silicon substrate 12 and the transistor 23. The conductor 518 can be provided using a material similar to that of the conductor 328 or the conductor 330.

[0094] In particular, the conductor 518 in the region in contact with the insulator 510 and the insulator 514 is preferably a conductor having a barrier property against oxygen, hydrogen, and water. With this configuration, the silicon substrate 12 and the transistor 23 can be separated by a layer having a barrier property against oxygen, hydrogen, and water, and diffusion of hydrogen from the silicon substrate 12 to the transistor 23 can be suppressed.

[0095] Above the insulator 516, the transistor 23 is provided.

[0096] As shown in Figures 11A and 11B, transistor 23 has a conductor 503 arranged so as to be embedded in insulator 514 and insulator 516, an insulator 520 arranged on insulator 516 and conductor 503, an insulator 522 arranged on insulator 520, an insulator 524 arranged on insulator 522, an oxide 530a arranged on insulator 524, an oxide 530b arranged on oxide 530a, conductors 542a and 542b arranged apart from each other on oxide 530b, an insulator 580 arranged on conductor 542a and conductor 542b and having an opening formed therebetween overlapping with conductor 542a and conductor 542b, an oxide 530c arranged on the bottom and side surfaces of the opening, an insulator 550 arranged on a surface on which oxide 530c is formed, and a conductor 560 arranged on a surface on which insulator 550 is formed.

[0097] 11A and 11B, it is preferable to dispose an insulator 544 between the oxide 530a, the oxide 530b, the conductor 542a, and the conductor 542b and the insulator 580. It is preferable that the conductor 560 has a conductor 560a provided inside the insulator 550 and a conductor 560b provided so as to be embedded inside the conductor 560a, as shown in FIGS. 11A and 11B. It is preferable that an insulator 574 is disposed on the insulator 580, the conductor 560, and the insulator 550, as shown in FIGS. 11A and 11B.

[0098] In the following, oxide 530a, oxide 530b, and oxide 530c may be collectively referred to as oxide 530.

[0099] In the transistor 23, a three-layer structure of the oxide 530a, the oxide 530b, and the oxide 530c is shown in the region where the channel is formed and in the vicinity thereof, but the present invention is not limited thereto. For example, a single layer of the oxide 530b, a two-layer structure of the oxide 530b and the oxide 530a, a two-layer structure of the oxide 530b and the oxide 530c, or a stacked structure of four or more layers may be provided. In the transistor 23, the conductor 560 is shown as having a two-layer stacked structure, but the present invention is not limited thereto. For example, the conductor 560 may have a single-layer structure or a stacked structure of three or more layers. The transistor 23 shown in FIG. 10, FIG. 11A, and FIG. 11B is just an example, and the present invention is not limited thereto, and an appropriate transistor may be used depending on the circuit configuration and the driving method.

[0100] Here, the conductor 560 functions as the gate electrode of the transistor 23, and the conductors 542a and 542b function as the source electrode and drain electrode, respectively. As described above, the conductor 560 is formed so as to be embedded in the opening of the insulator 580 and in the region sandwiched between the conductors 542a and 542b. The arrangement of the conductors 560, 542a, and 542b is selected in a self-aligned manner with respect to the opening of the insulator 580. That is, in the transistor 23, the gate electrode can be arranged in a self-aligned manner between the source electrode and the drain electrode. Therefore, the conductor 560 can be formed without providing a margin for alignment, so that the area occupied by the transistor 23 can be reduced. This allows the semiconductor device to be miniaturized and highly integrated.

[0101] Furthermore, since the conductor 560 is formed in a self-aligned manner in the region between the conductor 542a and the conductor 542b, the conductor 560 does not have a region overlapping with the conductor 542a or the conductor 542b. This makes it possible to reduce the parasitic capacitance formed between the conductor 560 and the conductor 542a and between the conductor 560 and the conductor 542b. As a result, the switching speed of the transistor 23 is improved, and the transistor 23 can have high frequency characteristics.

[0102] The conductor 560 may function as a first gate (also referred to as a top gate) electrode. The conductor 503 may function as a second gate (also referred to as a bottom gate) electrode. In this case, the threshold voltage of the transistor 23 can be controlled by changing the potential applied to the conductor 503 independently of the potential applied to the conductor 560. In particular, by applying a negative potential to the conductor 503, the threshold voltage of the transistor 23 can be made higher than 0 V, and the off-current can be reduced. Therefore, applying a negative potential to the conductor 503 can reduce the drain current when the potential applied to the conductor 560 is 0 V, compared to when a negative potential is not applied.

[0103] The conductor 503 is arranged to have a region overlapping with the oxide 530 and the conductor 560. In this manner, when a potential is applied to the conductor 560 and the conductor 503, an electric field generated from the conductor 560 and an electric field generated from the conductor 503 are connected, and a channel formation region formed in the oxide 530 can be covered. In this specification and the like, a transistor structure in which a channel formation region is electrically surrounded by the electric fields of the first gate electrode and the second gate electrode is referred to as a surrounded channel (s-channel) structure.

[0104] The conductor 503 has a structure similar to that of the conductor 518, and the conductor 503a is formed in contact with the inner walls of the openings of the insulator 514 and the insulator 516, and the conductor 503b is formed further inside. Note that, although the transistor 23 has a structure in which the conductor 503a and the conductor 503b are stacked, the present invention is not limited to this. For example, the conductor 503 may have a single layer or a stacked structure of three or more layers.

[0105] Here, the conductor 503a is preferably made of a conductive material having a function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, copper atoms, etc. (the impurities are less likely to permeate through). Alternatively, it is preferable to use a conductive material having a function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms, oxygen molecules, etc.) (the oxygen is less likely to permeate through). Note that in this specification and the like, the function of suppressing the diffusion of impurities or oxygen refers to the function of suppressing the diffusion of any one or all of the impurities or the oxygen.

[0106] For example, the conductor 503a has a function of suppressing the diffusion of oxygen, so that the conductor 503b can be prevented from being oxidized and causing a decrease in conductivity.

[0107] In addition, when the conductor 503 also functions as a wiring, it is preferable that the conductor 503b is made of a highly conductive material mainly composed of tungsten, copper, or aluminum. In that case, the conductor 503a is not necessarily provided. Although the conductor 503b is illustrated as a single layer, it may have a laminated structure, for example, a laminate of titanium or titanium nitride and the above-mentioned conductive material.

[0108] The insulators 520, 522, and 524 function as a second gate insulating film.

[0109] Here, the insulator 524 in contact with the oxide 530 is preferably an insulator containing more oxygen than the oxygen required for the stoichiometric composition. That is, an excess oxygen region is preferably formed in the insulator 524. By providing such an insulator containing excess oxygen in contact with the oxide 530, oxygen vacancies in the oxide 530 can be reduced and the reliability of the transistor 23 can be improved.

[0110] Specifically, it is preferable to use an oxide material from which some oxygen is released by heating as an insulator having an excess oxygen region. An oxide material from which oxygen is released by heating is an oxide material from which the amount of released oxygen converted into oxygen atoms is 1.0×10 18 atoms / cm 3 More than 1.0×10 19 atoms / cm 3 More preferably, 2.0×10 19 atoms / cm 3 or more than 3.0 x 10 20 atoms / cm 3 The oxide film is one having the above-mentioned properties. The surface temperature of the film during the TDS analysis is preferably in the range of 100° C. or higher and 700° C. or lower, or 100° C. or higher and 400° C. or lower.

[0111] In addition, the oxide 530 may be brought into contact with the insulator having the excess oxygen region and subjected to one or more of heat treatment, microwave treatment, and RF treatment. By carrying out such treatment, water or hydrogen in the oxide 530 can be removed. For example, a reaction occurs in the oxide 530 that breaks the bond of VoH, in other words, "V O H→V O In this case, some of the hydrogen generated may be combined with oxygen to form HO and removed from the oxide 530 or the insulator near the oxide 530. In addition, some of the hydrogen may be diffused or captured (also called gettering) in the conductor 542.

[0112] In addition, the microwave treatment is preferably performed using, for example, a device having a power source that generates high-density plasma, or a device having a power source that applies RF to the substrate side. For example, high-density oxygen radicals can be generated by using a gas containing oxygen and high-density plasma. In addition, by applying RF to the substrate side, oxygen radicals generated by high-density plasma can be efficiently introduced into the oxide 530 or an insulator near the oxide 530. In addition, the pressure of the microwave treatment may be 133 Pa or more, preferably 200 Pa or more, and more preferably 400 Pa or more. In addition, for example, oxygen and argon are used as gases to be introduced into the microwave treatment device, and the oxygen flow rate ratio (O2 / (O2+Ar)) is 50% or less, preferably 10% or more and 30% or less.

[0113] In addition, in the manufacturing process of the transistor 23, it is preferable to perform heat treatment in a state where the surface of the oxide 530 is exposed. The heat treatment may be performed, for example, at a temperature of 100° C. or higher and 450° C. or lower, more preferably 350° C. or higher and 400° C. or lower. Note that the heat treatment is performed in an atmosphere of nitrogen gas or an inert gas, or an atmosphere containing an oxidizing gas at 10 ppm or higher, 1% or higher, or 10% or higher. For example, the heat treatment is preferably performed in an oxygen atmosphere. In this way, oxygen is supplied to the oxide 530 to reduce oxygen deficiencies (V O ) can be reduced. The heat treatment may be performed under reduced pressure. Alternatively, the heat treatment may be performed in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas in order to compensate for the desorbed oxygen after the heat treatment in a nitrogen gas or inert gas atmosphere. Alternatively, the heat treatment may be performed in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas in order to compensate for the desorbed oxygen. Alternatively, the heat treatment may be performed in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas in succession to a heat treatment in a nitrogen gas or inert gas atmosphere.

[0114] In addition, by subjecting the oxide 530 to an oxygen supplying treatment, the oxygen vacancies in the oxide 530 are repaired by the supplied oxygen. In other words, OIn addition, the hydrogen remaining in the oxide 530 reacts with the oxygen supplied to the oxide 530, and the hydrogen can be removed as H2O (dehydrated). As a result, the hydrogen remaining in the oxide 530 recombines with the oxygen vacancies to form V O The formation of H can be suppressed.

[0115] When the insulator 524 has an excess oxygen region, it is preferable that the insulator 522 has a function of suppressing the diffusion of oxygen (eg, oxygen atoms, oxygen molecules, etc.) (the oxygen is less likely to permeate).

[0116] The insulator 522 preferably has a function of suppressing diffusion of oxygen and impurities, which prevents oxygen contained in the oxide 530 from diffusing toward the insulator 520. Furthermore, reaction of the conductor 503 with oxygen contained in the insulator 524 and the oxide 530 can be suppressed.

[0117] The insulator 522 is preferably a single layer or a multilayer insulator containing a so-called high-k material, such as aluminum oxide, hafnium oxide, oxide containing aluminum and hafnium (hafnium aluminate), tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO3), or (Ba,Sr)TiO3 (BST). As transistors become smaller and more highly integrated, problems such as leakage current may occur due to the thinning of the gate insulating film. By using a high-k material for the insulator that functions as the gate insulating film, it is possible to reduce the gate potential during transistor operation while maintaining the physical film thickness.

[0118] In particular, it is preferable to use an insulator containing an oxide of one or both of aluminum and hafnium, which are insulating materials having a function of suppressing the diffusion of impurities and oxygen (the oxygen is unlikely to permeate through them). As an insulator containing an oxide of one or both of aluminum and hafnium, it is preferable to use aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), or the like. When the insulator 522 is formed using such a material, the insulator 522 functions as a layer that suppresses release of oxygen from the oxide 530 and the intrusion of impurities such as hydrogen into the oxide 530 from the periphery of the transistor 23.

[0119] Alternatively, for example, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, or zirconium oxide may be added to these insulators. Alternatively, these insulators may be nitrided. Silicon oxide, silicon oxynitride, or silicon nitride may be stacked on the above insulators.

[0120] In addition, the insulator 520 is preferably thermally stable. For example, silicon oxide and silicon oxynitride are suitable because they are thermally stable. In addition, by combining a high-k material insulator with silicon oxide or silicon oxynitride, it is possible to obtain the insulator 520 having a thermally stable laminated structure with a high relative dielectric constant.

[0121] 11A and 11B, the second gate insulating film has a three-layer stack structure including the insulators 520, 522, and 524, but the second gate insulating film may have a single layer, two layers, or four or more layers. In this case, the second gate insulating film is not limited to a stack structure made of the same material, and may have a stack structure made of different materials.

[0122] In the transistor 23, it is preferable to use a metal oxide that functions as an oxide semiconductor for the oxide 530 including the channel formation region. For example, a metal oxide such as In-M-Zn oxide (wherein the element M is one or more selected from aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, etc.) may be used as the oxide 530. In particular, it is preferable that the In-M-Zn oxide applicable to the oxide 530 is CAAC-OS (C-Axls Aligned Crystal Oxide Semiconductor) or CAC-OS (Cloud-Aligned Composite Oxide Semiconductor). In addition, In-Ga oxide or In-Zn oxide may be used as the oxide 530. CAAC-OS and CAC-OS will be described later. Note that, when it is desired to increase the on-current of the transistor 23, it is preferable to use In-Zn oxide for the oxide 530. When In-Zn oxide is used for the oxide 530, examples include a stacked structure in which In-Zn oxide is used for the oxide 530a and In-M-Zn oxide is used for the oxide 530b and the oxide 530c, or a stacked structure in which In-M-Zn oxide is used for the oxide 530a and In-Zn oxide is used for either the oxide 530b or the oxide 530c.

[0123] In addition, it is preferable to use a metal oxide with a low carrier concentration for the transistor 23. In the case of lowering the carrier concentration of the metal oxide, it is sufficient to lower the impurity concentration in the metal oxide and to lower the defect state density. In this specification and the like, a low impurity concentration and a low defect state density are referred to as high purity intrinsic or substantially high purity intrinsic. Note that examples of impurities in the metal oxide include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, and the like.

[0124] In particular, hydrogen contained in the metal oxide reacts with oxygen that bonds with the metal atom to form water, which may cause oxygen vacancies in the metal oxide. In addition, when hydrogen enters an oxygen vacancy in the oxide 530, the oxygen vacancy and hydrogen combine to form V O May form H. V O H functions as a donor and may generate electrons as carriers. In addition, some of the hydrogen may bond with oxygen that bonds with metal atoms to generate electrons as carriers. Therefore, a transistor using a metal oxide containing a large amount of hydrogen is likely to have normally-on characteristics. In addition, hydrogen in a metal oxide is easily mobile due to stress such as heat or an electric field, so if a metal oxide contains a large amount of hydrogen, the reliability of the transistor may be deteriorated. In one embodiment of the present invention, V in the oxide 530 O It is preferable to reduce H as much as possible to obtain high-purity intrinsic or substantially high-purity intrinsic. O In order to obtain a metal oxide with a sufficiently reduced amount of H, it is important to remove impurities such as water and hydrogen from the metal oxide (sometimes referred to as dehydration or dehydrogenation treatment) and to supply oxygen to the metal oxide to compensate for the oxygen deficiency (sometimes referred to as oxygen addition treatment). O By using a metal oxide in which impurities such as H are sufficiently reduced for a channel formation region of a transistor, stable electrical characteristics can be imparted.

[0125] A defect in which hydrogen has entered an oxygen vacancy can function as a donor for a metal oxide. However, it is difficult to quantitatively evaluate the defect. Therefore, in a metal oxide, the carrier concentration may be used instead of the donor concentration. Therefore, in this specification, the carrier concentration assuming a state in which no electric field is applied may be used as a parameter of the metal oxide, instead of the donor concentration. In other words, the "carrier concentration" described in this specification may be rephrased as the "donor concentration".

[0126] Therefore, when a metal oxide is used for the oxide 530, it is preferable that hydrogen in the metal oxide is reduced as much as possible. Specifically, in the metal oxide, the hydrogen concentration obtained by secondary ion mass spectrometry (SIMS) is 1×10 20 atoms / cm 3 Less than 1 x 10 19 atoms / cm 3 less than 5×10 18 atoms / cm 3 less than 1×10 18 atoms / cm 3 By using a metal oxide in which impurities such as hydrogen are sufficiently reduced for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0127] In addition, when a metal oxide is used for the oxide 530, the carrier concentration of the metal oxide in the channel formation region is 1×10 18 cm -3 It is preferable that the value is less than 1×10 17 cm -3 More preferably, it is less than 1×10 16 cm -3 More preferably, it is less than 1×10 13 cm -3 More preferably, it is less than 1×10 12 cm -3 The lower limit of the carrier concentration of the metal oxide in the channel formation region is not particularly limited, but is preferably, for example, 1×10 -9 cm -3 It can be said that:

[0128] Furthermore, when a metal oxide is used for the oxide 530, contact between the conductor 542 (conductor 542a and conductor 542b) and the oxide 530 may cause oxygen in the oxide 530 to diffuse into the conductor 542, resulting in the oxidation of the conductor 542. The oxidation of the conductor 542 is likely to result in a decrease in the conductivity of the conductor 542. The diffusion of oxygen in the oxide 530 into the conductor 542 can be rephrased as the conductor 542 absorbing the oxygen in the oxide 530.

[0129] Furthermore, oxygen in the oxide 530 may diffuse into the conductor 542 (conductor 542a and conductor 542b), forming a foreign layer between the conductor 542a and the oxide 530b and between the conductor 542b and the oxide 530b. Since the foreign layer contains more oxygen than the conductor 542, the foreign layer is presumed to have insulating properties. In this case, the three-layer structure of the conductor 542, the foreign layer, and the oxide 530b can be regarded as a three-layer structure made of a metal-insulator-semiconductor, and may be referred to as a MIS (Metal-Insulator-Semiconductor) structure or a diode junction structure mainly based on the MIS structure.

[0130] Note that the above-mentioned different layer is not limited to being formed between the conductor 542 and the oxide 530b. For example, the different layer may be formed between the conductor 542 and the oxide 530c. Alternatively, the different layer may be formed between the conductor 542 and the oxide 530b and between the conductor 542 and the oxide 530c.

[0131] The metal oxide that functions as a channel formation region in the oxide 530 preferably has a band gap of 2 eV or more, preferably 2.5 eV or more. In this manner, by using a metal oxide with a wide band gap, the off-state current of the transistor can be reduced.

[0132] The oxide 530 has the oxide 530a below the oxide 530b, and thus can suppress the diffusion of impurities from structures formed below the oxide 530a to the oxide 530b. Also, the oxide 530 has the oxide 530c on the oxide 530b, and thus can suppress the diffusion of impurities from structures formed above the oxide 530c to the oxide 530b.

[0133] The oxide 530 preferably has a laminated structure of a plurality of oxide layers with different atomic ratios of each metal atom. Specifically, in the metal oxide used for the oxide 530a, the atomic ratio of element M among the constituent elements is preferably larger than the atomic ratio of element M among the constituent elements in the metal oxide used for the oxide 530b. In addition, in the metal oxide used for the oxide 530a, the atomic ratio of element M to In is preferably larger than the atomic ratio of element M to In in the metal oxide used for the oxide 530b. In addition, in the metal oxide used for the oxide 530b, the atomic ratio of In to element M is preferably larger than the atomic ratio of In to element M in the metal oxide used for the oxide 530a. In addition, the oxide 530c can be a metal oxide that can be used for the oxide 530a or the oxide 530b.

[0134] Specifically, the oxide 530a may be a metal oxide having an atomic ratio of In:Ga:Zn=1:3:4 or 1:1:0.5. The oxide 530b may be a metal oxide having an atomic ratio of In:Ga:Zn=4:2:3 or 1:1:1. The oxide 530c may be a metal oxide having an atomic ratio of In:Ga:Zn=1:3:4, Ga:Zn=2:1, or Ga:Zn=2:5. Specific examples of the oxide 530c having a layered structure include a layered structure of In:Ga:Zn=4:2:3 [atomic ratio] and In:Ga:Zn=1:3:4 [atomic ratio], a layered structure of Ga:Zn=2:1 [atomic ratio] and In:Ga:Zn=4:2:3 [atomic ratio], a layered structure of Ga:Zn=2:5 [atomic ratio] and In:Ga:Zn=4:2:3 [atomic ratio], and a layered structure of gallium oxide and In:Ga:Zn=4:2:3 [atomic ratio].

[0135] In addition, the energy of the conduction band minimum of the oxide 530a and the oxide 530c is preferably higher than that of the oxide 530b. In other words, the electron affinity of the oxide 530a and the oxide 530c is preferably smaller than that of the oxide 530b.

[0136] Here, the energy level of the conduction band minimum changes gradually at the junction of the oxide 530a, the oxide 530b, and the oxide 530c. In other words, it can be said that the energy level of the conduction band minimum at the junction of the oxide 530a, the oxide 530b, and the oxide 530c changes continuously or is a continuous junction. To achieve this, it is preferable to reduce the defect level density of the mixed layer formed at the interface between the oxide 530a and the oxide 530b and the interface between the oxide 530b and the oxide 530c.

[0137] Specifically, the oxides 530a and 530b, and the oxides 530b and 530c have a common element other than oxygen (as a main component), so that a mixed layer with a low density of defect states can be formed. For example, when the oxide 530b is an In-Ga-Zn oxide, the oxides 530a and 530c may be made of an In-Ga-Zn oxide, a Ga-Zn oxide, or a gallium oxide.

[0138] At this time, the main carrier path is the oxide 530b. By configuring the oxide 530a and the oxide 530c as described above, it is possible to reduce the defect state density at the interface between the oxide 530a and the oxide 530b and at the interface between the oxide 530b and the oxide 530c. As a result, the effect of interface scattering on carrier conduction is reduced, and the transistor 23 can obtain a high on-current.

[0139] Note that the semiconductor material that can be used for the oxide 530 is not limited to the above-mentioned metal oxides. A semiconductor material having a band gap (a semiconductor material that is not a zero-gap semiconductor) may be used as the oxide 530. For example, a semiconductor of a single element such as silicon, a compound semiconductor such as gallium arsenide, or a layered material that functions as a semiconductor (also called an atomic layer material, a two-dimensional material, or the like) is preferably used as the semiconductor material. In particular, it is preferable to use a layered material that functions as a semiconductor as the semiconductor material.

[0140] Here, in this specification and the like, the layered material is a general term for a group of materials having a layered crystal structure. The layered crystal structure is a structure in which layers formed by covalent bonds or ionic bonds are stacked via bonds weaker than covalent bonds or ionic bonds, such as van der Waals forces. The layered material has high electrical conductivity within a unit layer, that is, high two-dimensional electrical conductivity. By using a material that functions as a semiconductor and has high two-dimensional electrical conductivity in the channel formation region, a transistor with a large on-current can be provided.

[0141] Layered materials include graphene, silicene, and chalcogenides. Chalcogenides are compounds that contain chalcogen. Chalcogen is a general term for elements in group 16, including oxygen, sulfur, selenium, tellurium, polonium, and livermorium. Chalcogenides include transition metal chalcogenides and group 13 chalcogenides.

[0142] It is preferable to use, for example, a transition metal chalcogenide that functions as a semiconductor as the oxide 530. Specific examples of transition metal chalcogenides that can be used as the oxide 530 include molybdenum sulfide (representatively MoS2), molybdenum selenide (representatively MoSe2), molybdenum tellurium (representatively MoTe2), tungsten sulfide (representatively WS2), tungsten selenide (representatively WSe2), tungsten tellurium (representatively WTe2), hafnium sulfide (representatively HfS2), hafnium selenide (representatively HfSe2), zirconium sulfide (representatively ZrS2), and zirconium selenide (representatively ZrSe2).

[0143] Conductors 542a and 542b functioning as a source electrode and a drain electrode are provided on the oxide 530b. As the conductors 542a and 542b, it is preferable to use a metal element selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, ruthenium, iridium, strontium, and lanthanum, an alloy containing the above-mentioned metal element as a component, or an alloy combining the above-mentioned metal elements. For example, it is preferable to use tantalum nitride, titanium nitride, tungsten, a nitride containing titanium and aluminum, a nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, an oxide containing strontium and ruthenium, an oxide containing lanthanum and nickel, or the like. In addition, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel are preferable because they are conductive materials that are difficult to oxidize, or materials that maintain conductivity even when they absorb oxygen.Furthermore, metal nitride films such as tantalum nitride are preferable because they have barrier properties against hydrogen or oxygen.

[0144] 11A and 11B, the conductor 542a and the conductor 542b are shown as a single-layer structure, but may be a laminated structure of two or more layers. For example, a tantalum nitride film and a tungsten film may be laminated. A titanium film and an aluminum film may be laminated. Alternatively, a two-layer structure in which an aluminum film is laminated on a tungsten film, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a two-layer structure in which a copper film is laminated on a titanium film, or a two-layer structure in which a copper film is laminated on a tungsten film may be used.

[0145] In addition, there are three-layer structures in which a titanium film or titanium nitride film is laminated on the titanium film or titanium nitride film, an aluminum film or copper film is laminated on the titanium film or titanium nitride film, and a titanium film or titanium nitride film is further formed thereon, and a three-layer structure in which a molybdenum film or molybdenum nitride film is laminated on the molybdenum film or molybdenum nitride film, an aluminum film or copper film is laminated on the molybdenum film or molybdenum nitride film, and a molybdenum film or molybdenum nitride film is further formed thereon, etc. Note that a transparent conductive material containing indium oxide, tin oxide, or zinc oxide may be used.

[0146] 11A, regions 543a and 543b may be formed as low-resistance regions at and near the interface of the oxide 530 with the conductor 542a (conductor 542b). In this case, the region 543a functions as one of the source region and the drain region, and the region 543b functions as the other of the source region and the drain region. A channel formation region is formed in a region sandwiched between the regions 543a and 543b.

[0147] By providing the conductor 542a (conductor 542b) so as to be in contact with the oxide 530, the oxygen concentration in the region 543a (region 543b) may be reduced. Also, a metal compound layer containing a metal contained in the conductor 542a (conductor 542b) and a component of the oxide 530 may be formed in the region 543a (region 543b). In such a case, the carrier concentration in the region 543a (region 543b) increases, and the region 543a (region 543b) becomes a low-resistance region.

[0148] The insulator 544 is provided to cover the conductor 542a and the conductor 542b and suppresses oxidation of the conductor 542a and the conductor 542b. In this case, the insulator 544 may be provided to cover the side surface of the oxide 530 and to be in contact with the insulator 524.

[0149] The insulator 544 can be a metal oxide containing one or more selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, neodymium, lanthanum, magnesium, etc. In addition, the insulator 544 can also be made of silicon nitride oxide, silicon nitride, or the like.

[0150] In particular, it is preferable to use, as the insulator 544, an insulator containing an oxide of either or both of aluminum and hafnium, such as aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate). In particular, hafnium aluminate has higher heat resistance than a hafnium oxide film. Therefore, it is preferable because it is less likely to crystallize in a heat treatment in a later process. Note that the insulator 544 is not an essential component when the conductor 542a and the conductor 542b are made of a material having oxidation resistance or when the conductivity does not decrease significantly even when the conductor absorbs oxygen. It may be appropriately designed depending on the desired transistor characteristics.

[0151] The insulator 544 can prevent impurities such as water and hydrogen contained in the insulator 580 from diffusing to the oxide 530b through the oxide 530c and the insulator 550. The insulator 544 can also prevent the conductor 560 from being oxidized by excess oxygen contained in the insulator 580.

[0152] The insulator 550 functions as a first gate insulating film. The insulator 550 is preferably disposed so as to be in contact with the inside (top and side surfaces) of the oxide 530c. The insulator 550 is preferably formed using an insulator that contains excess oxygen and releases oxygen by heating, similar to the insulator 524 described above.

[0153] Specifically, silicon oxide having excess oxygen, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide to which fluorine is added, silicon oxide to which carbon is added, silicon oxide to which carbon and nitrogen are added, and silicon oxide having vacancies can be used. In particular, silicon oxide and silicon oxynitride are preferable because they are stable against heat.

[0154] By providing an insulator that releases oxygen when heated in contact with the top surface of the oxide 530c as the insulator 550, oxygen can be effectively supplied from the insulator 550 to the channel formation region of the oxide 530b through the oxide 530c. Similarly to the insulator 524, the concentration of impurities such as water or hydrogen in the insulator 550 is preferably reduced. The thickness of the insulator 550 is preferably 1 nm or more and 20 nm or less.

[0155] Furthermore, in order to efficiently supply excess oxygen contained in the insulator 550 to the oxide 530, a metal oxide may be provided between the insulator 550 and the conductor 560. The metal oxide preferably has a function of suppressing oxygen diffusion from the insulator 550 to the conductor 560. By providing a metal oxide having a function of suppressing oxygen diffusion, the diffusion of excess oxygen from the insulator 550 to the conductor 560 is suppressed. In other words, a decrease in the amount of excess oxygen supplied to the oxide 530 can be suppressed. Furthermore, oxidation of the conductor 560 due to the excess oxygen can be suppressed. As the metal oxide, a material that can be used for the insulator 544 may be used.

[0156] The insulator 550 may have a laminated structure, similar to the second gate insulating film. As transistors become smaller and more highly integrated, problems such as leakage current may occur due to the thinning of the gate insulating film. For this reason, by forming the insulator functioning as the gate insulating film into a laminated structure of a high-k material and a thermally stable material, it becomes possible to reduce the gate potential during transistor operation while maintaining the physical film thickness. In addition, a laminated structure that is thermally stable and has a high relative dielectric constant can be formed.

[0157] Although the conductor 560 functioning as the first gate electrode is shown as having a two-layer structure in FIGS. 11A and 11B, it may have a single-layer structure or a laminated structure of three or more layers.

[0158] The conductor 560a is preferably made of a conductive material having a function of suppressing diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (N2O, NO, NO2, etc.), and copper atoms. Alternatively, it is preferably made of a conductive material having a function of suppressing diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.). When the conductor 560a has a function of suppressing diffusion of oxygen, it is possible to suppress a decrease in conductivity due to oxidation of the conductor 560b caused by oxygen contained in the insulator 550. As a conductive material having a function of suppressing diffusion of oxygen, for example, tantalum, tantalum nitride, ruthenium, ruthenium oxide, or the like is preferably used. In addition, an oxide semiconductor applicable to the oxide 530 can be used as the conductor 560a. In that case, the conductor 560b can be formed by a sputtering method to reduce the electrical resistance value of the conductor 560a to make it a conductor. This can be called an OC (Oxide Conductor) electrode.

[0159] The conductor 560b is preferably made of a conductive material containing tungsten, copper, or aluminum as a main component. Since the conductor 560b also functions as wiring, it is preferable to use a conductor having high conductivity. For example, a conductive material containing tungsten, copper, or aluminum as a main component can be used. The conductor 560b may have a layered structure, for example, a layered structure of titanium or titanium nitride and the above conductive material.

[0160] The insulator 580 is provided on the conductor 542a and the conductor 542b via the insulator 544. The insulator 580 preferably has an excess oxygen region. For example, the insulator 580 preferably has silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide to which fluorine has been added, silicon oxide to which carbon has been added, silicon oxide to which carbon and nitrogen have been added, silicon oxide having voids, or a resin. In particular, silicon oxide and silicon oxynitride are preferable because they are thermally stable. In particular, silicon oxide and silicon oxide having voids are preferable because they allow for the easy formation of an excess oxygen region in a later step.

[0161] The insulator 580 preferably has an excess oxygen region. By providing the insulator 580, from which oxygen is released by heating, to have a region in contact with the oxide 530c, oxygen in the insulator 580 can be efficiently supplied to the oxide 530a and the oxide 530b through the oxide 530c. Note that the concentration of impurities such as water or hydrogen in the insulator 580 is preferably reduced.

[0162] The opening of the insulator 580 is formed to overlap the region between the conductor 542a and the conductor 542b. As a result, the conductor 560 is formed so as to be embedded in the opening of the insulator 580 and the region sandwiched between the conductor 542a and the conductor 542b.

[0163] In miniaturizing a semiconductor device, it is necessary to shorten the gate length, but it is also necessary to prevent the conductivity of the conductor 560 from decreasing. If the film thickness of the conductor 560 is increased for that purpose, the conductor 560 may have a shape with a high aspect ratio. In this embodiment, the conductor 560 is provided so as to be embedded in the opening of the insulator 580. Therefore, even if the conductor 560 has a shape with a high aspect ratio, the conductor 560 can be formed without collapsing during the process.

[0164] The insulator 574 is preferably provided in contact with a top surface of the insulator 580, a top surface of the conductor 560, and a top surface of the insulator 550. By forming the insulator 574 by a sputtering method, excess oxygen regions can be provided in the insulator 550 and the insulator 580. This allows oxygen to be supplied from the excess oxygen regions into the oxide 530.

[0165] For example, the insulator 574 can be a metal oxide containing one or more elements selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, magnesium, and the like.

[0166] In particular, aluminum oxide has high barrier properties and can suppress the diffusion of hydrogen and nitrogen even in a thin film of 0.5 nm to 3.0 nm. Therefore, aluminum oxide formed by sputtering can function as a barrier film against impurities such as hydrogen as well as an oxygen source.

[0167] An insulator 581 functioning as an interlayer film is preferably provided over the insulator 574. Like the insulator 524 and the like, the insulator 581 preferably has a reduced concentration of impurities such as water or hydrogen.

[0168] Furthermore, conductor 540a and conductor 540b are arranged in openings formed in insulator 581, insulator 574, insulator 580, and insulator 544. Conductor 540a and conductor 540b are provided facing each other with conductor 560 interposed therebetween. Conductor 540a and conductor 540b have the same structure as conductor 546 and conductor 548, which will be described later.

[0169] An insulator 582 is provided over the insulator 581. The insulator 582 is preferably made of a substance that has a barrier property against oxygen and hydrogen. Therefore, the insulator 582 can be made of a material similar to that of the insulator 514. For example, the insulator 582 is preferably made of a metal oxide such as aluminum oxide, hafnium oxide, or tantalum oxide.

[0170] In particular, aluminum oxide has a high blocking effect of preventing the film from permeating both oxygen and impurities such as hydrogen and moisture, which are factors that cause fluctuations in the electrical characteristics of a transistor. Therefore, aluminum oxide can prevent impurities such as hydrogen and moisture from entering the transistor 23 during and after the transistor manufacturing process. In addition, aluminum oxide can suppress the release of oxygen from the oxide that constitutes the transistor 23. Therefore, aluminum oxide is suitable for use as a protective film for the transistor 23.

[0171] An insulator 586 is provided over the insulator 582. The insulator 586 can be formed using a material similar to that of the insulator 320. By using a material with a relatively low dielectric constant for these insulators, parasitic capacitance between wirings can be reduced. For example, the insulator 586 can be formed using a silicon oxide film, a silicon oxynitride film, or the like.

[0172] Furthermore, conductors 546, conductors 548, etc. are embedded in insulators 520, 522, 524, 544, 580, 574, 581, 582, and 586.

[0173] The conductor 546 and the conductor 548 function as a plug or wiring that connects the silicon substrate 12 and the transistor 23. The conductor 546 and the conductor 548 can be formed using a material similar to that of the conductor 328 or the conductor 330.

[0174] After the transistor 23 is formed, an opening may be formed to surround the transistor 23, and an insulator with high barrier properties against hydrogen or water may be formed to cover the opening. By surrounding the transistor 23 with the insulator with high barrier properties, it is possible to prevent moisture and hydrogen from entering from the outside. Alternatively, a plurality of transistors 23 may be collectively surrounded by an insulator with high barrier properties against hydrogen or water. When an opening is formed to surround the transistor 23, for example, it is preferable to form an opening that reaches the insulator 514 or the insulator 522 and form the insulator with high barrier properties in contact with the insulator 514 or the insulator 522, because this can serve as part of the manufacturing process of the transistor 23. As the insulator with high barrier properties against hydrogen or water, for example, a material similar to that of the insulator 522 may be used.

[0175] Next, the conductor 22 and the conductor 21 are provided. The conductor 22 and the conductor 21 function as plugs or wiring that connect the silicon substrate 12 and the transistor 23.

[0176] A metal film containing an element selected from molybdenum, titanium, tantalum, tungsten, aluminum, copper, chromium, neodymium, and scandium, or a metal nitride film containing the above-mentioned element (tantalum nitride film, titanium nitride film, molybdenum nitride film, tungsten nitride film), etc., can be used for the conductor 21 and the conductor 22. Alternatively, a conductive material such as indium tin oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide, or indium tin oxide with added silicon oxide can also be used.

[0177] 10, the conductor 21 and the conductor 22 are shown to have a single-layer structure, but are not limited to this configuration and may have a laminated structure of two or more layers. For example, a conductor having barrier properties and a conductor having high adhesion to the conductor having high conductivity may be formed between a conductor having barrier properties and a conductor having high conductivity.

[0178] With this structure, miniaturization or high integration can be achieved in a semiconductor device including a transistor including an oxide semiconductor.

[0179] 12A and 12B are modifications of the transistor 23 shown in Fig. 11A and 11B. Fig. 12A is a cross-sectional view of the transistor 23 in the channel length direction, and Fig. 12B is a cross-sectional view of the transistor 23 in the channel width direction. Note that the structures shown in Fig. 12A and 12B can also be applied to other transistors, such as the transistor 23, included in the semiconductor device of one embodiment of the present invention.

[0180] 12A and 12B differs from the transistor 23 shown in Figures 11A and 11B in that it includes an insulator 402 and an insulator 404. It also differs from the transistor 23 shown in Figures 11A and 11B in that an insulator 552 is provided in contact with a side surface of the conductor 540a and an insulator 552 is provided in contact with a side surface of the conductor 540b. It also differs from the transistor 23 shown in Figures 11A and 11B in that it does not include an insulator 520.

[0181] 12A and 12B, the insulator 402 is provided over the insulator 512. Furthermore, the insulator 404 is provided over the insulator 574 and the insulator 402.

[0182] 12A and 12B, the insulator 514, the insulator 516, the insulator 522, the insulator 524, the insulator 544, the insulator 580, and the insulator 574 are patterned, and the insulator 404 covers them. That is, the insulator 404 contacts the top surface of the insulator 574, the side surface of the insulator 574, the side surface of the insulator 580, the side surface of the insulator 544, the side surface of the insulator 524, the side surface of the insulator 522, the side surface of the insulator 516, the side surface of the insulator 514, and the top surface of the insulator 402. As a result, the oxide 530 and the like are isolated from the outside by the insulator 404 and the insulator 402.

[0183] The insulators 402 and 404 preferably have a high function of suppressing diffusion of hydrogen (for example, at least one of hydrogen atoms, hydrogen molecules, and the like) or water molecules. For example, the insulators 402 and 404 are preferably made of silicon nitride or silicon nitride oxide, which are materials with high hydrogen barrier properties. This can suppress diffusion of hydrogen and the like into the oxide 530, thereby suppressing deterioration of the characteristics of the transistor 23. Therefore, the reliability of the semiconductor device of one embodiment of the present invention can be improved.

[0184] The insulator 552 is provided in contact with the insulator 581, the insulator 404, the insulator 574, the insulator 580, and the insulator 544. The insulator 552 preferably has a function of suppressing diffusion of hydrogen or water molecules. For example, the insulator 552 is preferably made of an insulator having a high hydrogen barrier property, such as silicon nitride, aluminum oxide, or silicon nitride oxide. In particular, silicon nitride is preferably used as the insulator 552 because it has a high hydrogen barrier property. By using a material having a high hydrogen barrier property as the insulator 552, impurities such as water or hydrogen can be suppressed from diffusing from the insulator 580 or the like to the oxide 530 through the conductor 540a and the conductor 540b. Furthermore, oxygen contained in the insulator 580 can be suppressed from being absorbed by the conductor 540a and the conductor 540b. As described above, the reliability of the semiconductor device of one embodiment of the present invention can be improved.

[0185] 13A and 13B are modifications of the transistor shown in FIG. 12A and FIG. 12B. FIG. 13A is a cross-sectional view of the transistor in the channel length direction, and FIG. 13B is a cross-sectional view of the transistor in the channel width direction. The transistor shown in FIG. 13A and FIG. 13B is different from the transistor shown in FIG. 12A and FIG. 12B in that the oxide 530c has a two-layer structure of an oxide 530c1 and an oxide 530c2.

[0186] The oxide 530c1 is in contact with the top surface of the insulator 524, the side surface of the oxide 530a, the top surface and side surface of the oxide 530b, the side surfaces of the conductors 542a and 542b, the side surface of the insulator 544, and the side surface of the insulator 580. The oxide 530c2 is in contact with the insulator 550.

[0187] The oxide 530c1 may be, for example, an In-Zn oxide. The oxide 530c2 may be the same material as that used for the oxide 530c when the oxide 530c has a single-layer structure. For example, the oxide 530c2 may be a metal oxide with an atomic ratio of n:Ga:Zn=1:3:4, Ga:Zn=2:1, or Ga:Zn=2:5.

[0188] By forming the oxide 530c in a two-layer structure of the oxide 530c1 and the oxide 530c2, the on-current of the transistor can be increased compared to when the oxide 530c has a single-layer structure. Therefore, the transistor can be, for example, a power MOS transistor. The oxide 530c of the transistor shown in FIG. 11A and FIG. 11B can also have a two-layer structure of the oxide 530c1 and the oxide 530c2.

[0189] 13A and 13B can be used as the transistor 23 to increase the on-state current of the transistor 23, for example.

[0190] This embodiment mode can be implemented in appropriate combination with configurations described in other embodiment modes or the like.

[0191] (Embodiment 3) In this embodiment, structures of CAC-OS and CAAC-OS, which are metal oxides that can be used for the OS transistors described in the above embodiment, will be described. Note that in this specification and the like, CAC represents an example of a function or a material structure, and CAAC represents an example of a crystal structure.

[0192] <Metal oxide composition> CAC-OS or CAC-metal oxide has a conductive function in a part of the material and an insulating function in a part of the material, and has a function as a semiconductor as a whole. When CAC-OS or CAC-metal oxide is used in an active layer of a transistor, the conductive function is a function of flowing electrons (or holes) as carriers, and the insulating function is a function of not flowing electrons as carriers. By making the conductive function and the insulating function act complementarily, a switching function (on / off function) can be imparted to CAC-OS or CAC-metal oxide. By separating the respective functions in CAC-OS or CAC-metal oxide, both functions can be maximized.

[0193] Moreover, the CAC-OS or CAC-metal oxide has a conductive region and an insulating region. The conductive region has the above-mentioned conductive function, and the insulating region has the above-mentioned insulating function. In addition, in the material, the conductive region and the insulating region may be separated at the nanoparticle level. In addition, the conductive region and the insulating region may be unevenly distributed in the material. In addition, the conductive region may be observed to be connected in a cloud shape with a blurred periphery.

[0194] In addition, in the CAC-OS or CAC-metal oxide, the conductive regions and the insulating regions may each be dispersed in the material with a size of 0.5 nm to 10 nm, preferably 0.5 nm to 3 nm.

[0195] In addition, the CAC-OS or CAC-metal oxide is composed of components having different band gaps. For example, the CAC-OS or CAC-metal oxide is composed of a component having a wide gap due to an insulating region and a component having a narrow gap due to a conductive region. In this configuration, when carriers are caused to flow, the carriers mainly flow in the component having the narrow gap. In addition, the component having the narrow gap acts complementarily on the component having the wide gap, and carriers also flow in the component having the wide gap in conjunction with the component having the narrow gap. Therefore, when the above CAC-OS or CAC-metal oxide is used in the channel formation region of a transistor, a high current driving force in the on state of the transistor, that is, a large on-current and a high field effect mobility can be obtained.

[0196] That is, CAC-OS or CAC-metal oxide can also be called a matrix composite or a metal matrix composite.

[0197] <Metal oxide structure> Oxide semiconductors are classified into single-crystal oxide semiconductors and non-single-crystal oxide semiconductors other than those. Examples of non-single-crystal oxide semiconductors include CAAC-OS, polycrystalline oxide semiconductors, nanocrystalline oxide semiconductors (nc-OS), amorphous-like oxide semiconductors (a-like OS), and amorphous oxide semiconductors.

[0198] CAAC-OS has a c-axis orientation and a distorted crystal structure in which multiple nanocrystals are connected in the ab-plane direction. The distortion refers to a portion where the lattice orientation changes between a region with a uniform lattice arrangement and a region with a different uniform lattice arrangement in the region where multiple nanocrystals are connected.

[0199] Nanocrystals are basically hexagonal, but may be non-regular hexagonal. In addition, the lattice arrangement may be pentagonal, heptagonal, etc., due to the distortion. In CAAC-OS, no clear grain boundary can be confirmed even in the vicinity of the distortion. In other words, it is found that the formation of grain boundaries is suppressed by the distortion of the lattice arrangement. This is thought to be because CAAC-OS can tolerate distortion due to the fact that the arrangement of oxygen atoms in the ab-plane direction is not dense and the bond distance between atoms changes due to the substitution of metal elements.

[0200] CAAC-OS also tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium and oxygen (hereinafter, In layer) and a layer containing element M, zinc, and oxygen (hereinafter, (M, Zn) layer) are stacked. Note that indium and element M can be substituted for each other, and when element M in an (M, Zn) layer is substituted for indium, it can also be represented as an (In, M, Zn) layer. When indium in an In layer is substituted for element M, it can also be represented as an (In, M) layer.

[0201] The CAAC-OS is an oxide semiconductor with high crystallinity. On the other hand, since no clear crystal grain boundaries can be identified in the CAAC-OS, it can be said that the decrease in electron mobility due to the crystal grain boundaries is unlikely to occur. In addition, since the crystallinity of an oxide semiconductor can be decreased by the inclusion of impurities or the generation of defects, the CAAC-OS can be said to be an oxide semiconductor with few impurities and defects (oxygen vacancies, etc.). Therefore, the physical properties of an oxide semiconductor having the CAAC-OS are stable. Therefore, an oxide semiconductor having the CAAC-OS is resistant to heat and has high reliability. In addition, the CAAC-OS is stable against high temperatures (so-called thermal budget) in the manufacturing process. Therefore, the use of the CAAC-OS in an OS transistor can increase the degree of freedom in the manufacturing process.

[0202] The nc-OS has periodic atomic arrangement in a microscopic region (for example, a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In addition, the nc-OS does not show regularity in the crystal orientation between different nanocrystals. Therefore, no orientation is seen throughout the film. Therefore, depending on the analysis method, the nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor.

[0203] The a-like OS is an oxide semiconductor having a structure between the nc-OS and an amorphous oxide semiconductor. The a-like OS has a void or low-density region. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS.

[0204] Oxide semiconductors have a variety of structures and have different characteristics. The oxide semiconductor of one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, an nc-OS, and a CAAC-OS.

[0205] <Transistor Having Oxide Semiconductor> Next, the case where the oxide semiconductor is used for a transistor will be described.

[0206] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0207] In addition, it is preferable to use an oxide semiconductor having a low carrier concentration for the transistor. In order to reduce the carrier concentration of the oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced to reduce the density of defect states. In this specification and the like, a semiconductor having a low impurity concentration and a low density of defect states is referred to as a highly pure intrinsic semiconductor or a substantially highly pure intrinsic semiconductor.

[0208] Furthermore, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and therefore the density of trap states might also be low.

[0209] In addition, charges trapped in the trap states of an oxide semiconductor take a long time to disappear and may behave as if they are fixed charges. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high density of trap states may have unstable electrical characteristics.

[0210] Therefore, in order to stabilize the electrical characteristics of a transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. In order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in a nearby film. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, and the like.

[0211] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0212] When an oxide semiconductor contains silicon or carbon, which is one of the group 14 elements, defect levels are formed in the oxide semiconductor. For this reason, the concentrations of silicon or carbon in the oxide semiconductor and those near the interface with the oxide semiconductor (concentrations obtained by secondary ion mass spectrometry (SIMS)) are calculated as 2×10 18 atoms / cm 3 Less than or equal to 2 x 10 17 atoms / cm 3 The following applies.

[0213] Furthermore, when an oxide semiconductor contains an alkali metal or an alkaline earth metal, defect levels are formed and carriers are generated in some cases. Therefore, a transistor using an oxide semiconductor containing an alkali metal or an alkaline earth metal is likely to have normally-on characteristics. For this reason, it is preferable to reduce the concentration of the alkali metal or the alkaline earth metal in the oxide semiconductor. Specifically, when the concentration of the alkali metal or the alkaline earth metal in the oxide semiconductor obtained by SIMS is 1×10 18 atoms / cm3 Less than or equal to 2 x 10 16 atoms / cm 3 To the following:

[0214] Furthermore, when nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier concentration increases, and the oxide semiconductor is likely to become n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor is likely to have normally-on characteristics. Therefore, it is preferable that the nitrogen content in the oxide semiconductor is reduced as much as possible. For example, the nitrogen concentration in the oxide semiconductor is less than 5×10 19 atoms / cm 3 Less than 5 x 10 18 atoms / cm 3 Less than or equal to 1×10 18 atoms / cm 3 Less than 5×10, more preferably 17 atoms / cm 3 The following applies.

[0215] Furthermore, hydrogen contained in an oxide semiconductor reacts with oxygen bonded to a metal atom to form water, which may form an oxygen vacancy. When hydrogen enters the oxygen vacancy, electrons serving as carriers may be generated. In addition, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons serving as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. For this reason, it is preferable to reduce hydrogen in the oxide semiconductor as much as possible. Specifically, when the hydrogen concentration in an oxide semiconductor measured by SIMS is 1×10 20 atoms / cm 3 Less than 1 x 10 19 atoms / cm 3 less than 5×10 18 atoms / cm 3 less than 1×10 18 atoms / cm 3 Less than.

[0216] When an oxide semiconductor in which impurities are sufficiently reduced is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0217] This embodiment mode can be implemented in appropriate combination with configurations described in other embodiment modes or the like.

[0218] (Embodiment 4) In this embodiment mode, examples of electronic devices in which the semiconductor device or the like described in the above embodiment modes is incorporated will be described with reference to FIGS.

[0219] The robot 7100 includes an illuminance sensor, a microphone, a camera, a speaker, a display, various sensors (infrared sensor, ultrasonic sensor, acceleration sensor, piezoelectric sensor, optical sensor, gyro sensor, etc.), a moving mechanism, etc. The electronic component 100A or 100D functions as a switch for controlling the power supply for driving these peripheral devices.

[0220] The microphone has a function of detecting an acoustic signal such as a user's voice and an environmental sound. The speaker has a function of emitting an audio signal such as a voice and an alarm sound. The robot 7100 can analyze an audio signal inputted through the microphone and emit a necessary audio signal from the speaker. The robot 7100 can communicate with a user using the microphone and the speaker.

[0221] The camera has a function of capturing an image of the surroundings of the robot 7100. The robot 7100 also has a function of moving using a moving mechanism. The robot 7100 can capture an image of the surroundings using the camera and detect the presence or absence of an obstacle when moving by analyzing the image.

[0222] The flying object 7120 has a propeller, a camera, a battery, etc., and has a function of flying autonomously. The electronic component 100A or 100D functions as a switch for controlling the power supply for driving these peripheral devices.

[0223] The cleaning robot 7140 has a display arranged on the top surface, multiple cameras arranged on the sides, a brush, operation buttons, various sensors, etc. The electronic component 100A or 100D functions as a switch for controlling the power supply for driving these peripheral devices. Although not shown, the cleaning robot 7140 is equipped with tires, a suction port, etc. The cleaning robot 7140 can move by itself, detect dirt, and suck up the dirt from a suction port provided on the bottom surface.

[0224] The automobile 7160 has an engine, tires, brakes, a steering device, a camera, etc. The electronic component 100A or 100D functions as a switch for controlling the power supply for driving these peripheral devices.

[0225] The electronic component 100A or 100D can be incorporated into a TV device 7200 (television receiver), a smartphone 7210, a PC (personal computer) 7220, 7230, a game machine 7240, a game machine 7260, and the like.

[0226] For example, the electronic component 100A or 100D built into the TV device 7200 functions as a switch for controlling the power supply for driving the TV device 7200.

[0227] The smartphone 7210 is an example of a portable information terminal. The smartphone 7210 includes a microphone, a camera, a speaker, various sensors, and a display unit. The electronic component 100A or 100D functions as a switch for controlling the power supply for driving these peripheral devices.

[0228] PC7220 and PC7230 are examples of a notebook PC and a desktop PC, respectively. A keyboard 7232 and a monitor device 7233 can be connected to PC7230 wirelessly or via wire. Game machine 7240 is an example of a portable game machine. Game machine 7260 is an example of a desktop game machine. A controller 7262 is connected to game machine 7260 wirelessly or via wire. Electronic component 100A or 100D functions as a switch for controlling a power supply for driving each component.

[0229] This embodiment mode can be implemented in appropriate combination with structures described in other embodiment modes.

[0230] (Additional Notes Regarding the Description of the Present Specification, etc.) The above embodiment and each configuration in the embodiment will be described below with additional notes.

[0231] The configurations shown in each embodiment can be combined with the configurations shown in other embodiments or examples to form one aspect of the present invention. In addition, when multiple configuration examples are shown in one embodiment, the configuration examples can be combined as appropriate.

[0232] In addition, the content (or a part of the content) described in one embodiment can be applied to, combined with, or replaced by another content (or a part of the content) described in that embodiment, and / or the content (or a part of the content) described in one or more other embodiments.

[0233] The contents described in the embodiments refer to contents described in each embodiment using various figures or contents described using text in the specification.

[0234] In addition, a figure (or a part thereof) described in one embodiment can be combined with another part of that figure, with another figure (or a part thereof) described in that embodiment, and / or with a figure (or a part thereof) described in one or more other embodiments to form even more figures.

[0235] In addition, in the present specification and the like, in the block diagrams, the components are classified by function and shown as mutually independent blocks. However, in actual circuits and the like, it is difficult to separate the components by function, and there may be cases where one circuit is involved in multiple functions, or where one function is involved across multiple circuits. Therefore, the blocks in the block diagrams are not limited to the components described in the specification, and may be rephrased appropriately according to the situation.

[0236] In addition, in the drawings, the size, layer thickness, or region are shown at an arbitrary size for convenience of explanation. Therefore, they are not necessarily limited to the scale. Note that the drawings are shown diagrammatically for clarity, and are not limited to the shapes or values ​​shown in the drawings. For example, it is possible to include variations in signals, voltages, or currents due to noise, or variations in signals, voltages, or currents due to timing deviations.

[0237] In addition, the positional relationship of components shown in the drawings is relative. Therefore, when describing components with reference to the drawings, terms such as "above" and "below" that indicate the positional relationship may be used for convenience. The positional relationship of components is not limited to the contents described in this specification, and can be rephrased appropriately depending on the situation.

[0238] In this specification and the like, when describing the connection relationship of a transistor, the term "one of the source or drain" (or first electrode or first terminal) is used, and the other of the source and drain is used as "the other of the source or drain" (or second electrode or second terminal). This is because the source and drain of a transistor vary depending on the structure or operating conditions of the transistor. Note that the source and drain of a transistor can be appropriately referred to as source (drain) terminal, source (drain) electrode, etc. depending on the situation.

[0239] In addition, the terms "electrode" and "wiring" used in this specification and the like do not limit the functionality of these components. For example, an "electrode" may be used as part of a "wiring", and vice versa. Furthermore, the terms "electrode" and "wiring" include cases where multiple "electrodes" or "wirings" are formed integrally.

[0240] In addition, in this specification and the like, voltage and potential can be interchanged as appropriate. Voltage is a potential difference from a reference potential, and if the reference potential is a ground voltage (earth voltage), for example, voltage can be interchanged with potential. Ground potential does not necessarily mean 0V. Note that potential is relative, and the potential applied to wiring, etc. may be changed depending on the reference potential.

[0241] In this specification and the like, a node can be referred to as a terminal, a wiring, an electrode, a conductive layer, a conductor, an impurity region, etc. depending on a circuit configuration, a device structure, etc. Also, a terminal, a wiring, etc. can be referred to as a node.

[0242] In this specification, A and B are connected means that A and B are electrically connected. Here, A and B are electrically connected means a connection in which an electrical signal between A and B can be transmitted when an object (an element such as a switch, a transistor element, or a diode, or a circuit including the element and wiring) exists between A and B. Note that when A and B are electrically connected, this includes a case in which A and B are directly connected. Here, A and B are directly connected means a connection in which an electrical signal between A and B can be transmitted through wiring (or electrodes) between A and B without passing through the object. In other words, a direct connection means a connection that can be regarded as the same circuit diagram when expressed as an equivalent circuit.

[0243] In this specification, a switch refers to a device that has a function of controlling whether a current flows or not by being in a conductive state (on state) or a non-conductive state (off state), or a device that has a function of selecting and switching a path for a current to flow.

[0244] In this specification, the channel length refers to, for example, in a top view of a transistor, a region where a semiconductor (or a portion in the semiconductor through which current flows when the transistor is on) and a gate overlap, or a distance between the source and drain in a region where a channel is formed.

[0245] In this specification, the channel width refers to, for example, the length of the region where a semiconductor (or the portion in the semiconductor through which current flows when the transistor is on) and a gate electrode overlap, or the length of the portion where a source and a drain face each other in a region in which a channel is formed.

[0246] In this specification and the like, the terms "film" and "layer" can be interchanged depending on the circumstances. For example, the term "conductive layer" can be changed to the term "conductive film". Or, for example, the term "insulating film" can be changed to the term "insulating layer". [Explanation of symbols]

[0247] 10: semiconductor device, 10A: semiconductor device, 10B: semiconductor device, 10C: semiconductor device, 10D: semiconductor device, 10E: semiconductor device, 11: device, 11A: device, 11B: device, 11C: device, 11D: device, 12: silicon substrate, 20: semiconductor device, 21A: conductor, 21B: conductor, 22A: conductor, 22B: conductor, 23: transistor, 23A: transistor, 23B: transistor, 23B_1: transistor, 23B_2: transistor, 23C: transistor, 23D: transistor, 23R: region, 24A: opening, 24B: opening, 25: transistor, 25A: oxide layer, 25B: oxide layer, 26: transistor, 26A: gate electrode, 26B: gate electrode, 26B_1: conductor, 26B_2: conductor, 27A: region, 27B: region, 28: oxide layer, 29: conductor, 30: electrode layer, 31A: conductor, 31B: conductor, 51A: region, 51B: region, 60: battery protection circuit, 61: battery, 100A: electronic component, 100B: electronic component, 100C: electronic component, 100D: electronic component, 101: substrate, 102: adhesive layer, 103: resin layer, 104A: metal wiring, 104B: metal wiring Wire, 105A: electrode, 105B: electrode, 106: housing, 107: heat sink, 199: power storage device, 320: insulator, 322: insulator, 324: insulator, 326: insulator, 328: conductor, 330: conductor, 350: insulator, 352: insulator, 354: insulator, 356: conductor, 402: insulator, 404: insulator, 503: conductor, 503a: conductor, 503b: conductor, 510: insulator, 512: insulator, 514: insulator, 516: insulator, 518: conductor, 520: insulator, 522: insulator, 524: insulator, 530: oxide, 530a: oxide, 5 30b: oxide, 530c: oxide, 530c1: oxide, 530c2: oxide, 540a: conductor, 540b: conductor, 542: conductor, 542a: conductor, 542b: conductor, 543a: region, 543b: region, 544: insulator, 546: conductor, 548: conductor, 550: insulator, 552: insulator, 560: conductor, 560a: conductor, 560b: conductor, 574: insulator, 580: insulator, 581: insulator, 582: insulator, 586: insulator, 610: conductor, 612: conductor, 7100: robot, 7120: flying object, 7140: cleaning robot,7160: automobile, 7200: TV device, 7210: smartphone, 7220: PC, 7230: PC, 7232: keyboard, 7233: monitor device, 7240: game machine, 7260: game machine, 7262: controller,

Claims

1. A silicon substrate; A device disposed above the silicon substrate; an electrode layer disposed over the device; The electrode layer has a first conductor, the device includes a transistor and a second conductor; the transistor includes an oxide semiconductor film, the oxide semiconductor film includes a channel formation region of the transistor, The silicon substrate is provided with electrical conductivity, the first conductor is electrically connected to a source of the transistor; the second conductor is electrically connected to the drain of the transistor and to the silicon substrate through an opening in the device; the second conductor has a region in contact with a lower surface of the oxide semiconductor film.

2. A silicon substrate; A device disposed above the silicon substrate; an electrode layer disposed over the device; The electrode layer has a first conductor, the device includes a first transistor, a second transistor, a second conductor, and a third conductor; the first transistor includes a first oxide semiconductor film, the first oxide semiconductor film includes a channel formation region of the first transistor, the second transistor includes a second oxide semiconductor film, the second oxide semiconductor film has a channel formation region of the second transistor, The silicon substrate is provided with electrical conductivity, the first conductor is electrically connected to a source of the first transistor and a source of the second transistor; the second conductor is electrically connected to a drain of the first transistor and to the silicon substrate through a first opening in the device; the third conductor is electrically connected to a drain of the second transistor and to the silicon substrate through a second opening in the device; the second conductor has a region in contact with a lower surface of the first oxide semiconductor film, the third conductor has a region in contact with a lower surface of the second oxide semiconductor film.

3. In claim 1 or 2, The semiconductor device, wherein the silicon substrate is imparted with p-type conductivity.

4. In any one of claims 1 to 3, the silicon substrate and the device are covered with a resin layer; The resin layer is provided inside a housing of the semiconductor device.

5. In any one of claims 1 to 4, The semiconductor device further comprises a heat sink provided on the silicon substrate via an insulating layer.

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