Semiconductor device

Abstract

A semiconductor device with low power consumption and stable operation is provided. A logic circuit including a circuit structure of a transistor having an oxide semiconductor in a channel formation region. The logic circuit is a two-wire logic circuit of 2-input and 2-output. The transistors constituting the logic circuit each have a gate and a back gate. One of the gate and the back gate of the transistor electrically connected to a wiring supplying a high power supply potential is electrically connected to an input terminal. The other of the gate and the back gate of the transistor electrically connected to the wiring supplying the high power supply potential is electrically connected to an output terminal. One of a source and a drain of the transistor electrically connected to a wiring supplying a low power supply potential is electrically connected to the output terminal. The gate or the back gate of the transistor electrically connected to the wiring supplying the low power supply potential is electrically connected to the input terminal.

Description

TECHNICAL FIELD

[0001] One embodiment of the present application relates to a semiconductor device.

[0002] In addition, one embodiment of the present application relates to a semiconductor device. Note that one embodiment of the present application is not limited to the above technical field. The technical field of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present application relates to a process, a machine, manufacture, or a composition of matter.

[0003] Note that in this specification and the like, a semiconductor device refers to an apparatus that can function by utilizing semiconductor characteristics. A display device, a light-emitting device, a memory device, an electro-optical device, an electric power storage device, a control system, a semiconductor circuit, and an electronic device each include a semiconductor device in some cases. BACKGROUND

[0004] A transistor whose channel formation region is formed using a metal oxide (also referred to as an oxide semiconductor) has extremely small off-state current flowing therethrough at the time of off, and is thus expected to be used for a logic circuit for low power consumption. For example, Patent Document 1 discloses a unipolar inverter circuit including an OS transistor which is an n-channel transistor.

[0005] [Prior Art Documents]

[0006] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent Application Publication No. 2011 / 84731 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] When a logic circuit is formed using only n-channel transistors, there is a problem in that the output voltage is decreased by a voltage corresponding to the threshold voltage. In addition, there is a problem in that power consumption is increased because of a structure in which a through current flows between power supply lines.

[0010] In addition, in a transistor whose channel formation region is formed using silicon (a Si transistor), the electrical characteristics of a transistor included in a logic circuit change when the transistor is exposed to high temperature. The change in electrical characteristics causes a decrease in on / off ratio of the transistor, and thus there is a problem in that normal circuit operation cannot be maintained.

[0011] In view of the above problems, one object of one embodiment of the present application is to provide a semiconductor device with high reliability. Another object of one embodiment of the present application is to provide a semiconductor device with low power consumption.

[0012] Note that the description is not intended to limit other objects. Note that one embodiment of the present application does not require achieving all the objects. Other objects are apparent from the description, the attached drawings, the claims, and the like, and can be extracted from the description.

[0013] Means for solving the technical problem

[0014] A semiconductor device includes a first input terminal and a second input terminal, a first output terminal and a second output terminal, a first wiring and a second wiring, and first to fourth transistors. One of a source and a drain of the first transistor is electrically connected to the first wiring, one of a gate and a back gate is electrically connected to the first input terminal, the other of the source and the drain and the other of the gate and the back gate are electrically connected to the second output terminal, one of a source and a drain of the second transistor is electrically connected to the first wiring, one of a gate and a back gate is electrically connected to the second input terminal, the other of the source and the drain and the other of the gate and the back gate are electrically connected to the first output terminal, the gate and the back gate of the third transistor are electrically connected to the first input terminal, one of a source and a drain is electrically connected to the first output terminal, the other of the source and the drain is electrically connected to the second wiring, and the gate and the back gate of the fourth transistor are electrically connected to the second input terminal, one of a source and a drain is electrically connected to the second output terminal, the other of the source and the drain is electrically connected to the second wiring.

[0015] A semiconductor device includes: a first input terminal and a second input terminal; a first output terminal and a second output terminal; first to third wirings; and first to eighth transistors. In the first transistor, one of its source and drain is electrically connected to the first wiring, and one of its gate and back gate is electrically connected to the first input terminal. The other of its source and drain, and the other of its gate and back gate, are electrically connected to the gate and back gate of a second transistor. In the second transistor, one of its source and drain is electrically connected to the second wiring, and the other of its source and drain is electrically connected to the second output terminal. In the third transistor, one of its source and drain is electrically connected to the first wiring, and one of its gate and back gate is electrically connected to the second input terminal. The other of its source and drain, and the other of its gate and back gate, are electrically connected to the gate and back gate of a fourth transistor. In the fourth transistor, one of its source and drain is electrically connected to the second wiring, and the other of its source and drain is electrically connected to the first output terminal. The gate and back gate of the fifth transistor are electrically connected to the first input terminal, one of its source and drain is electrically connected to the gate and back gate of the fourth transistor, and the other of its source and drain is electrically connected to the third wiring. The gate and back gate of the sixth transistor are electrically connected to the first input terminal, one of its source and drain is electrically connected to the first output terminal, and the other of its source and drain is electrically connected to the third wiring. The gate and back gate of the seventh transistor are electrically connected to the second input terminal, one of its source and drain is electrically connected to the gate and back gate of the second transistor, and the other of its source and drain is electrically connected to the third wiring. Furthermore, the gate and back gate of the eighth transistor are electrically connected to the second input terminal, one of its source and drain is electrically connected to the second output terminal, and the other of its source and drain is electrically connected to the third wiring.

[0016] In one aspect of the semiconductor device of the present invention, it is preferable that a first potential provided to a first wiring is higher than a second potential provided to a second wiring.

[0017] In one aspect of the semiconductor device of the present invention, the channel forming regions of the first to fourth transistors preferably contain metal oxides.

[0018] In one aspect of the semiconductor device of the present invention, the channel forming regions of the first to eighth transistors preferably contain metal oxides.

[0019] In one aspect of the semiconductor device of the present invention, the metal oxide preferably contains at least In (indium) or Zn (zinc).

[0020] In one aspect of the semiconductor device of the present invention, the metal oxide preferably contains Ga (gallium).

[0021] A semiconductor device includes a plurality of switching circuits and a plurality of logic circuits. The logic circuit includes a first input terminal and a second input terminal, a first output terminal and a second output terminal, a first to third wiring, and a first to eighth transistor. One of a source and a drain of the first transistor is electrically connected to the first wiring, one of a gate and a back gate is electrically connected to the first input terminal, the other of the source and the drain and the other of the gate and the back gate are electrically connected to a gate and a back gate of the second transistor, one of a source and a drain of the second transistor is electrically connected to the second wiring, the other of the source and the drain is electrically connected to the second output terminal, one of a source and a drain of the third transistor is electrically connected to the first wiring, one of a gate and a back gate is electrically connected to the second input terminal, the other of the source and the drain and the other of the gate and the back gate are electrically connected to a gate and a back gate of the fourth transistor, one of a source and a drain of the fourth transistor is electrically connected to the second wiring, the other of the source and the drain is electrically connected to the first output terminal, a gate and a back gate of the fifth transistor are electrically connected to the first input terminal, one of a source and a drain is electrically connected to the gate and the back gate of the fourth transistor, the other of the source and the drain is electrically connected to the third wiring, a gate and a back gate of the sixth transistor are electrically connected to the first input terminal, one of a source and a drain is electrically connected to the first output terminal, the other of the source and the drain is electrically connected to the third wiring, a gate and a back gate of the seventh transistor are electrically connected to the second input terminal, one of a source and a drain is electrically connected to the gate and the back gate of the second transistor, the other of the source and the drain is electrically connected to the third wiring, and a gate and a back gate of the eighth transistor are electrically connected to the second input terminal, one of a source and a drain is electrically connected to the second output terminal, the other of the source and the drain is electrically connected to the third wiring.

[0022] In the semiconductor device of one embodiment, a first potential supplied to the first wiring is preferably higher than a second potential supplied to the second wiring.

[0023] In the semiconductor device of one embodiment, the channel formation regions of the first to eighth transistors preferably contain a metal oxide.

[0024] In the semiconductor device of one embodiment, the switching circuit preferably includes a transistor, and the channel formation region of the transistor contains a metal oxide.

[0025] In the semiconductor device of one embodiment, a potential corresponding to data held in the logic circuit can be held by making any of the plurality of switching circuits non-conductive.

[0026] In the semiconductor device of one embodiment, the metal oxide contains at least In (indium) or Zn (zinc).

[0027] In one aspect of the semiconductor device of the present invention, the metal oxide preferably contains Ga (gallium).

[0028] Note that other aspects of the present invention are described in the following description and accompanying drawings of the embodiments.

[0029] Invention Effects

[0030] According to one aspect of the present invention, a semiconductor device with excellent reliability can be provided. Furthermore, according to another aspect of the present invention, a semiconductor device with excellent low power consumption can be provided.

[0031] Note that other aspects of the present invention are described in the following description and accompanying drawings of the embodiments. Attached Figure Description

[0032] [Figure 1] illustrates an example of the structure of a semiconductor device. (A) is a block diagram, and (B) is a circuit diagram.

[0033] [Figure 2] illustrates an example of the structure of a semiconductor device. (A) is a circuit diagram, (B) is a timing diagram, and (C) is a diagram showing the circuit symbols.

[0034] [Figure 3] illustrates an example of the structure of a semiconductor device. (A) is a circuit symbol, and (B) is a diagram.

[0035] [ FIG. 4 [ ] is a circuit diagram illustrating an example of the structure of a semiconductor device.

[0036] [Figure 5] illustrates an example of the structure of a semiconductor device. (A) is a circuit diagram, and (B) is a circuit diagram.

[0037] [Figure 6] illustrates an example of the structure of a semiconductor device. (A) is a circuit diagram, and (B) is a timing diagram.

[0038] [ FIG. 7 [ ] is a circuit diagram illustrating an example of the structure of a semiconductor device.

[0039] [Figure 8] illustrates an example of the structure of a semiconductor device. (A) is a perspective view, and (B) is a perspective view.

[0040] [Figure 9] illustrates an example of the structure of a semiconductor device. (A) is a block diagram, (B) is a circuit diagram, and (C) is a circuit diagram.

[0041] [Figure 10] illustrates an example of the structure of a semiconductor device. (A) is a diagram showing the symbol of the circuit, (B) is a diagram showing the symbol of the circuit, (C) is a circuit diagram, and (D) is a timing diagram.

[0042] [FIG. 11] Explanation of a structure example of a semiconductor device, (A) is a circuit diagram, (B) is a circuit diagram, (C) is a circuit diagram, and (D) is a circuit diagram.

[0043] [FIG. 12] Explanation of a structure example of a semiconductor device, (A) is a circuit diagram, and (B) is a diagram showing a symbol of a circuit symbol.

[0044] [FIG. 13] Explanation of a structure example of a semiconductor device, (A) is a circuit diagram, and (B) is a diagram showing a symbol of a circuit symbol.

[0045] [ FIG. 14 ] is a timing chart explaining a structure example of a semiconductor device.

[0046] [FIG. 15] Explanation of a structure example of a semiconductor device, (A) is a circuit diagram, and (B) is a circuit diagram.

[0047] [ FIG. 16 ] is a circuit diagram explaining a structure example of a semiconductor device.

[0048] [FIG. 17] Illustration of a structure example of a transistor, (A) is a cross-sectional view, and (B) is a cross-sectional view.

[0049] [FIG. 18] Illustration of a structure example of a transistor, (A) is a top view, (B) is a cross-sectional view, and (C) is a cross-sectional view.

[0050] [FIG. 19] Illustration of a structure example of a transistor, (A) is a top view, (B) is a cross-sectional view, and (C) is a cross-sectional view.

[0051] [FIG. 20] Illustration of a structure example of a transistor, (A) is a top view, (B) is a cross-sectional view, and (C) is a cross-sectional view.

[0052] [FIG. 21] Illustration of a structure example of a transistor, (A) is a top view, (B) is a cross-sectional view, and (C) is a cross-sectional view.

[0053] [FIG. 22] Illustration of a structure example of a transistor, (A) is a top view, (B) is a cross-sectional view, and (C) is a cross-sectional view.

[0054] [FIG. 23] is a diagram showing structure examples of (A) to (D) of an electronic device.

[0055] [FIG. 24] Explanation of operation of a semiconductor device, (A) is a graph, and (B) is a graph. DETAILED DESCRIPTION

[0056] Hereinafter, embodiments will be described with reference to drawings. However, the embodiments can be implemented in many different ways, and it is readily apparent to those skilled in the art that the ways and details thereof can be changed variously without departing from the spirit and scope of the present application. Therefore, the present application should not be interpreted as being limited to the content described in the following embodiments.

[0057] Note that in this specification and the like, the terms "first", "second", "third", and the like are used, and these terms mean only different names and do not mean a certain order or a certain order of sequence. For example, in this specification and the like, the terms "first", "second", "third", and the like are used in describing specific example embodiments, and do not mean a certain order or a certain order of sequence. Therefore, the terms "first", "second", "third", and the like should not be interpreted as being limited to the meaning of the above terms.

[0058] Note that in the drawings, the same reference numerals are used throughout the drawings to designate the same elements, components, or the like common to the drawings. The same applies to the like.

[0059] In this specification and the like, a metal oxide means an oxide of a metal in a broad sense. Metal oxides are classified into an oxide insulator, an oxide conductor (including a transparent oxide conductor), an oxide semiconductor (also referred to as an Oxide Semiconductor), and the like.

[0060] For example, in the case where a metal oxide is used for a channel formation region of a transistor, the metal oxide is sometimes referred to as an oxide semiconductor. In other words, in the case where a metal oxide has at least one of amplifying function, rectifying function, and switching function, the metal oxide can be referred to as a metal oxide semiconductor. That is, a transistor including a metal oxide in a channel formation region can be referred to as an "oxide semiconductor transistor", an "OS transistor". Similarly, the above "transistor using an oxide semiconductor" is a transistor including a metal oxide in a channel formation region.

[0061] (Embodiment 1)

[0062] A structure of a semiconductor device of one embodiment of the present application will be described.

[0063] FIG. 1Ais a block diagram of a semiconductor device of this embodiment. The semiconductor device 100 described in this embodiment can be roughly divided into a signal generation circuit 101 and a logic circuit 102.

[0064] Note that the semiconductor device in this specification and the like means all devices that can operate by utilizing semiconductor characteristics. Thus, the signal generation circuit 101 and the logic circuit 102 are each referred to as a semiconductor device in some cases.

[0065] The signal generation circuit 101 has a function of outputting an input signal and an inverted input signal from a terminal IN and a terminal INB. The signal generation circuit 101 includes a circuit (denoted as Si / Cir. in the drawing) formed of an Si transistor. The signal generation circuit 101 can be formed by appropriately designing using a CMOS circuit, a sequential circuit, and a combination circuit.

[0066] The logic circuit 102 includes a circuit (denoted as OS / Cir. in the drawing) formed of an OS transistor. The logic circuit 102 is a combination circuit. As one example thereof, there is an inverter circuit (also referred to as a NOT circuit). The logic circuit 102 has a function of outputting an output signal and an inverted output signal from a terminal OUT and a terminal OUTB in response to an input signal and an inverted input signal.

[0067] The logic circuit 102 is a two-wire combination circuit formed of an OS transistor. Unlike an Si transistor, an OS transistor has small variation in electrical characteristics in a high-temperature environment. Thus, the logic circuit 102 can operate with high reliability in a high-temperature environment.

[0068] FIG. 1B is a circuit diagram showing a specific circuit structure of the logic circuit 102. FIG. 1B The logic circuit 102 illustrated in the drawing is a two-wire logic circuit used as an inverter circuit.

[0069] FIG. 1B The logic circuit 102 illustrated in the drawing includes transistors 111 to 114. In addition, FIG. 1B A wiring VDDL to which a high power supply potential VDD is supplied and a wiring VSSL to which a low power supply potential VSS (e.g., a ground potential) is supplied are shown.

[0070] One of a gate and a back gate of the transistor 111 is connected to the terminal IN to which the input signal is supplied. One of a source and a drain of the transistor 111 is connected to the wiring VDDL. The other of the source and the drain of the transistor 111 is connected to the terminal OUTB from which the inverted output signal is output. The other of the gate and the back gate of the transistor 111 is connected to the terminal OUTB from which the inverted output signal is output. Note that each terminal can be referred to as a wiring.

[0071] The transistor 111 has a function of controlling whether or not the terminal OUTB has a high-level potential according to the potential VDD in correspondence with the potential applied to the gate becoming an on state (may be referred to as an on) or an off state (may be referred to as an off). The transistor 111 has a function of controlling whether the transistor is of a depletion type (may be referred to as always on) or an enhancement type (may be referred to as always off) in correspondence with the potential applied to the back gate. The transistor 111 is also referred to as a first transistor.

[0072] One of the gate and the back gate of the transistor 112 is connected to the terminal INB to which the inverted input signal is supplied. One of the source and the drain of the transistor 112 is connected to the wiring VDDL. The other of the source and the drain of the transistor 112 is connected to the terminal OUT which outputs the output signal. The other of the gate and the back gate of the transistor 112 is connected to the terminal OUT which outputs the output signal.

[0073] The transistor 112 has a function of controlling whether or not the terminal OUT has a high-level potential according to the potential VDD in correspondence with the potential applied to the gate becoming an on or an off. The transistor 112 has a function of being controlled to be always on or always off in correspondence with the potential applied to the back gate. The transistor 112 is also referred to as a second transistor.

[0074] The gate and the back gate of the transistor 113 are connected to the terminal IN to which the input signal is supplied. Further, a structure in which either of the gate and the back gate of the transistor 113 is connected to the terminal IN can be employed. One of the source and the drain of the transistor 113 is connected to the terminal OUT which outputs the output signal. The other of the source and the drain of the transistor 113 is connected to the wiring VSSL.

[0075] The transistor 113 has a function of controlling whether or not the terminal OUT has a low-level potential according to the potential VSS in correspondence with the potential applied to the gate and the back gate of the terminal IN becoming an on or an off. The transistor 113 is also referred to as a third transistor.

[0076] The gate and the back gate of the transistor 114 are connected to the terminal INB to which the inverted input signal is supplied. Further, a structure in which either of the gate and the back gate of the transistor 114 is connected to the terminal INB can be employed. One of the source and the drain of the transistor 114 is connected to the terminal OUTB which outputs the inverted output signal. The other of the source and the drain of the transistor 114 is connected to the wiring VSSL.

[0077] The transistor 114 has a function of controlling whether or not the terminal OUTB has a low-level potential according to the potential VSS in correspondence with the potential applied to the gate and the back gate of the terminal INB becoming an on or an off. The transistor 114 is also referred to as a fourth transistor 114.

[0078] Next, with reference to FIG. 2A to FIG. 2C DescriptionFIG. 1B The operation of the logic circuit 102 shown.

[0079] FIG. 2A The operation of the logic circuit 102 shown. FIG. 1B The same circuit diagram, FIG. 2B The timing chart shown to explain FIG. 2A the operation of the logic circuit 102.

[0080] In the timing chart shown, FIG. 2B at times T1 to T2 and times T3 to T4, the input signal supplied to the terminal IN is made high, and the inverted input signal supplied to the terminal INB is made low. The transistor 111 becomes always on, and the transistor 113 becomes on. The transistor 112 becomes always off, and the transistor 114 becomes off. The terminal OUT has a low potential according to the potential VSS. The terminal OUTB has a high potential according to the potential VDD.

[0081] By adopting this structure, the potential applied to the back gate of the transistor can be switched. For example, FIG. 3A In the circuit symbol of the transistor 115 shown, the gate of the transistor is denoted by g, the back gate of the transistor is denoted by bg, the source of the transistor is denoted by s, and the drain of the transistor is denoted by d. FIG. 3B is a graph showing the relationship between the current (Id) flowing through the drain of the transistor and the voltage (Vg) of the gate when the potential of the source is 0 V. As shown in the graph, when the voltage of the back gate is the potential VSS (Vbg = 0), the threshold voltage can be positively shifted to realize always off. In addition, when the voltage of the back gate is the potential VDD (Vbg = VDD), the threshold voltage can be negatively shifted to realize always on.

[0082] The back gate of the transistor 111 is applied with a high potential, and the back gate of the transistor 112 is applied with a low potential. As a result, the transistor 111 becomes an always on transistor, and the transistor 112 becomes an always off transistor. The transistor 111 can be used as an always on transistor, and thus the amount of current flowing through the terminal OUTB can be increased. In addition, the transistor 112 can be used as an always off transistor, and thus the through current between the wiring VDDL and the wiring VSSL can be surely reduced.

[0083] In the timing chart shown, FIG. 2B at times T2 to T3, the input signal supplied to the terminal IN is made low, and the inverted input signal supplied to the terminal INB is made high. The transistor 111 becomes always off, and the transistor 113 becomes off. The transistor 112 becomes always on, and the transistor 114 becomes on. The terminal OUT has a high potential according to the potential VDD. The terminal OUTB has a low potential according to the potential VSS.

[0084] A low-level potential is applied to the back gate of transistor 111, and a high-level potential is applied to the back gate of transistor 112. As a result, transistor 111 becomes a normally-off transistor, and transistor 112 becomes a normally-on transistor. Transistor 111 can be used as a normally-off transistor, thereby effectively reducing the through current between wiring VDDL and wiring VSSL. Additionally, transistor 112 can be used as a normally-on transistor, which can increase the amount of current flowing through terminal OUT.

[0085] in addition, FIG. 2A The circuit diagram of logic circuit 102 shown has the function of a two-wire inverter circuit. FIG. 2C The symbol shown is for a two-wire circuit.

[0086] Note that, although FIG. 1B The diagram shows transistors 111 and 112 with terminals IN and INB connected to their back gate sides. However, it can also be configured as follows: FIG. 4 The logic circuit 102A shown in the circuit diagram adopts a structure in which terminals IN and INB are connected on the gate side.

[0087] In a transistor, the thickness of the gate insulating film on the gate side or the gate insulating film on the back gate side is made different. Furthermore, by switching... FIG. 1B and FIG. 4 The connection allows adjustment of the electric field strength in the channel formation region. This, in turn, allows adjustment of the threshold voltage drift. Furthermore, it is preferable that the gate insulating film on the side connecting terminals IN and INB is thinner. By employing this structure, excellent switching characteristics can be achieved, depending on the input signals and inverted input signals provided to terminals IN and INB.

[0088] By adopting the structure described above, a semiconductor device with logic circuits composed of OS transistors can achieve low power consumption while maintaining excellent reliability.

[0089] Next, explain the relationship with FIG. 1B Examples of different logic circuit structures.

[0090] FIG. 5A The logic circuit 102B shown is related to FIG. 1B The same circuit diagram is used as a two-wire logic circuit for inverter circuits.

[0091] FIG. 5A The logic circuit 102B shown includes transistors 121 to 128. Additionally, FIG. 5A The diagram shows wiring VDHL, which is provided with a high power supply potential VDH; wiring VDDL, which is provided with a high power supply potential VDD; and wiring VSSL, which is provided with a low power supply potential VSS. The high power supply potential VDH is a potential higher than the high power supply potential VDD.

[0092] One of the gate and the back gate of the transistor 121 is connected to a terminal IN to which an input signal is supplied. One of a source and a drain of the transistor 121 is connected to a line VDHL. The other of the source and the drain of the transistor 121 is connected to the gate and the back gate of the transistor 122. The other of the gate and the back gate of the transistor 121 is connected to the gate and the back gate of the transistor 122.

[0093] The transistor 121 has a function of controlling whether or not the potential of the gate and the back gate of the transistor 122 becomes a potential according to the potential VDH in accordance with the potential applied to the gate being turned on or off. The transistor 121 has a function of being controlled to be always on or always off in accordance with the potential applied to the back gate. The transistor 121 is also referred to as a first transistor.

[0094] One of a source and a drain of the transistor 122 is connected to a line VDDL. The other of the source and the drain of the transistor 122 is connected to a terminal OUTB.

[0095] The transistor 122 has a function of controlling whether or not the terminal OUTB has a high-level potential according to the potential VDD in accordance with the potentials applied to the gate and the back gate being turned on or off. The transistor 122 is also referred to as a second transistor.

[0096] One of the gate and the back gate of the transistor 123 is connected to a terminal INB to which an inverted input signal is supplied. One of a source and a drain of the transistor 123 is connected to the line VDHL. The other of the source and the drain of the transistor 123 is connected to the gate and the back gate of the transistor 124. The other of the gate and the back gate of the transistor 123 is connected to the gate and the back gate of the transistor 124.

[0097] The transistor 123 has a function of controlling whether or not the potential of the gate and the back gate of the transistor 124 becomes a potential according to the potential VDH in accordance with the potential applied to the gate being turned on or off. The transistor 123 has a function of controlling the transistor to be always on or always off in accordance with the potential applied to the back gate. The transistor 123 is also referred to as a third transistor.

[0098] One of a source and a drain of the transistor 124 is connected to the line VDDL. The other of the source and the drain of the transistor 124 is connected to a terminal OUT.

[0099] The transistor 124 has a function of controlling whether or not the terminal OUT has a high-level potential according to the potential VDD in accordance with the potentials applied to the gate and the back gate being turned on or off. The transistor 124 is also referred to as a fourth transistor.

[0100] The gate and back gate of the transistor 125 are connected to a terminal IN to which an input signal is supplied. Alternatively, a structure in which either the gate or the back gate of the transistor 125 is connected to the terminal IN can be employed. One of the source and drain of the transistor 125 is connected to the gate and back gate of the transistor 124. The other of the source and drain of the transistor 125 is connected to a wiring VSSL.

[0101] The transistor 125 has a function of controlling whether or not the potential of the gate and back gate of the transistor 124 becomes a low-potential according to the potential VSS in accordance with the potential of the terminal IN applied to the gate and back gate becoming on or off. The transistor 125 is also referred to as a fifth transistor.

[0102] The gate and back gate of the transistor 126 are connected to a terminal IN to which an input signal is supplied. Alternatively, a structure in which either the gate or the back gate of the transistor 126 is connected to the terminal IN can be employed. One of the source and drain of the transistor 126 is connected to a terminal OUT from which an output signal is output. The other of the source and drain of the transistor 126 is connected to a wiring VSSL.

[0103] The transistor 126 has a function of controlling whether or not the terminal OUT has a low-potential according to the potential VSS in accordance with the potential of the terminal IN applied to the gate and back gate becoming on or off. The transistor 126 is also referred to as a sixth transistor.

[0104] The gate and back gate of the transistor 127 are connected to a terminal INB to which an inverted input signal is supplied. Alternatively, a structure in which either the gate or the back gate of the transistor 127 is connected to the terminal INB can be employed. One of the source and drain of the transistor 127 is connected to the gate and back gate of the transistor 122. The other of the source and drain of the transistor 127 is connected to a wiring VSSL.

[0105] The transistor 127 has a function of controlling whether or not the potential of the gate and back gate of the transistor 122 becomes a low-potential according to the potential VSS in accordance with the potential of the terminal INB applied to the gate and back gate becoming on or off. The transistor 127 is also referred to as a seventh transistor.

[0106] The gate and back gate of the transistor 128 are connected to a terminal INB to which an inverted input signal is supplied. Alternatively, a structure in which either the gate or the back gate of the transistor 128 is connected to the terminal INB can be employed. One of the source and drain of the transistor 128 is connected to a terminal OUTB from which an inverted output signal is output. The other of the source and drain of the transistor 128 is connected to a wiring VSSL.

[0107] The transistor 128 has a function of becoming on or off in accordance with the potential applied to the gate and the back gate of the terminal INB to control whether or not the terminal OUTB has a low potential according to the potential VSS. The transistor 128 is also referred to as an eighth transistor.

[0108] Note that, although the structure in which the terminals IN and INB are connected to the back gate side of the transistors 121 and 123 is shown in FIG. 5A , a structure in which the terminals IN and INB are connected to the gate side of the transistors 121 and 123 can also be employed as shown in the circuit diagram of the logic circuit 102C. FIG. 5B

[0109] In the transistor, the thickness of the gate insulating film on the gate side or the thickness of the gate insulating film on the back gate side is made different. Further, the electric field intensity to the channel formation region can be adjusted by switching the connection of FIG. 5A and FIG. 5B . Thus, the amount of shift of the threshold voltage can be adjusted. In addition, it is preferable that the gate insulating film on the side to which the terminals IN and INB are connected be thinner. By employing this structure, the switching characteristics depending on the input signal and the inverted input signal supplied to the terminals IN and INB can be made excellent.

[0110] Next, the operation of the logic circuit 102B shown in FIG. 6A to FIG. 6B will be described with reference to FIG. 5A .

[0111] FIG. 6A The circuit diagram shown in FIG. 5A is the same as that shown in FIG. 6B , and is used to explain the operation of FIG. 6A . In FIG. 6A , the node of the gate and the back gate of the transistor 122 is denoted as a node P. In addition, the node of the gate and the back gate of the transistor 124 is denoted as a node PB.

[0112] In the timing chart shown in FIG. 6B , at times T5 to T6 and times T7 to T8, the input signal supplied to the terminal IN is made high and the inverted input signal supplied to the terminal INB is made low. The transistor 121 becomes always on, and the transistors 125 and 126 become on. The transistor 123 becomes always off, and the transistors 127 and 128 become off. The node P becomes a high potential according to the potential VDH, and the transistor 122 becomes on. The node PB becomes a low potential according to the potential VSS, and the transistor 124 becomes off. The terminal OUT has a low potential according to the potential VSS. The terminal OUTB has a high potential according to the potential VDD.

[0113] ​The back gate of the transistor 121 is supplied with a high-level potential, and the back gate of the transistor 123 is supplied with a low-level potential. As a result, the transistor 121 becomes a normally-on transistor, and the transistor 123 becomes a normally-off transistor. The transistor 121 can function as a normally-on transistor, and thus the current amount flowing through the gate and the back gate of the transistor 122 can be increased. In addition, the transistor 123 can function as a normally-off transistor, and thus the through current between the wiring VDHL and the wiring VSSL can be effectively reduced.

[0114] In addition, in the configuration of FIG. 6A , the node P can be set to a potential according to the potential VDH which is higher than the potential VDD. Thus, the voltage applied between the gate and the source of the transistor 122 can be increased, and thus the voltage drop corresponding to the threshold voltage can be reduced, and the potential of the terminal OUTB can be more accurately set to the potential VDD.

[0115] FIG. 24A and FIG. 24B A graph showing waveforms of the input signal (IN), the inverted input signal (INB), the output signal (OUT), and the inverted output signal (OUTB) obtained by circuit simulation is shown. FIG. 24A In the case of FIG. 24B , the power supply voltage is 2.5 V. The signal (output voltage) of the output signal corresponding to the voltage (input voltage) of the input signal is obtained in each condition.

[0116] In the timing chart shown in FIG. 6B , at the time T6 to T7, the input signal supplied to the terminal IN is set to a low level, and the inverted input signal supplied to the terminal INB is set to a high level. The transistor 121 becomes normally-off, and the transistors 125 and 126 become off. The transistor 123 becomes normally-on, and the transistors 127 and 128 become on. The node P becomes a low-level potential according to the potential VSS, and the transistor 122 becomes off. The node PB becomes a high-level potential according to the potential VDH, and the transistor 124 becomes on. The terminal OUT has a low-level potential according to the potential VSS. The terminal OUTB has a high-level potential according to the potential VDD.

[0117] The back gate of the transistor 121 is supplied with a low-level potential, and the back gate of the transistor 123 is supplied with a high-level potential. As a result, the transistor 121 becomes a normally-off transistor, and the transistor 123 becomes a normally-on transistor. The transistor 121 can function as a normally-off transistor, and thus the through current between the wiring VDHL and the wiring VSSL can be effectively reduced. In addition, the transistor 123 can function as a normally-on transistor, and thus the current amount flowing through the gate and the back gate of the transistor 124 can be increased.

[0118] In addition, in the configuration ofFIG. 6A In the configuration of FIG. 6, the node PB can be made to be a potential according to the potential VDH higher than the potential VDD. Thereby, the voltage applied between the gate and the source of the transistor 124 can be increased, and thus the voltage drop corresponding to the threshold voltage can be reduced, and the potential of the terminal OUTB can be made to be the potential VDD more surely.

[0119] Further, the logic circuit 102B shown in FIG. 6 has a function of a two-wire inverter circuit. Thus, the logic circuit 102B can be used as a two-wire inverter circuit. FIG. 6A FIG. 2A Similarly, the two-wire circuit symbol shown in FIG. 6 is represented by the symbol shown in FIG. 7. FIG. 2C

[0120] By employing the configuration described above, the semiconductor device having the logic circuit composed of the OS transistor can achieve low power consumption while achieving operation with excellent reliability. Further, the voltage drop of the signal to be output can be suppressed.

[0121] Further, by applying the configuration described above, a basic combinational circuit can be composed.

[0122] FIG. 7 is a circuit diagram of a logic circuit to which the configuration of FIG. 4 FIG. 6 is applied. FIG. 7 The logic circuit 102D shown in FIG. 6 includes transistors 131 to 138. Further, the logic circuit 102D has a function of a NAND circuit. FIG. 7 A wiring VDDL to which a high power supply potential VDD is supplied and a wiring VSSL to which a low power supply potential VSS is supplied are shown. Terminals IN1, IN1B, IN2, and terminals IN2B are terminals to which input signals are supplied. Terminals OUT and OUTB are terminals to which output signals are supplied. From the terminal OUT, an output signal of NAND (NOR of inverted input signals) corresponding to the input signals is obtained, and from the terminal OUTB, an output signal of NAND (AND of inverted input signals) corresponding to the input signals is obtained. Further, the function of the logic circuit can be switched by exchanging the signals input to the respective terminals. FIG. 7 The truth table of the logic circuit shown in FIG. 6 is shown in Table 1.

[0123] [Table 1]

[0124] IN1 IN1B IN2 IN2B OUT OUTB 0 1 0 1 1 0 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 0 1

[0125] By employing the combinational circuit described above, a complex circuit such as a counter, a serial-parallel converter, a processor, or the like can be implemented. Since the circuit described above can be composed of the OS transistor, good switching characteristics can be maintained even in a high-temperature environment. Further, the through current can be reduced to lower power consumption, and the voltage drop corresponding to the threshold voltage and the like can be suppressed.

[0126] ​​In FIG. 8, an example of a perspective view of an IC in which the above-described logic circuit that is a semiconductor device is assembled is shown.

[0127] FIG. 8A An example of an IC is shown. FIG. 8A The IC 7000A shown includes leads 7001 and a circuit portion 7003A. The IC 7000A is mounted on a printed circuit board 7002, for example. By combining a plurality of such IC dies and electrically connecting them to each other on the printed circuit board 7002, a substrate (circuit board 7004) on which electronic components are mounted is completed. The circuit portion 7003A is provided with various circuits shown in the above-described embodiments that are cut into one die or a plurality of dies. The circuit portion 7003A is roughly divided into an OS transistor layer 7031 and a wiring layer 7032.

[0128] In addition, the OS transistor layer can be a single layer or a structure in which wiring layers are laminated. Specifically, FIG. 8B Another example of an IC is shown. FIG. 8B The IC 7000B shown includes leads 7001 and a circuit portion 7003B. The IC 7000B is mounted on a printed circuit board 7002, for example. By combining a plurality of such IC dies and electrically connecting them to each other on the printed circuit board 7002, a substrate (circuit board 7004) on which electronic components are mounted is completed. The circuit portion 7003B is provided with various circuits shown in the above-described embodiments that are cut into one die or a plurality of dies. The circuit portion 7003A is roughly divided into an OS transistor layer 7031, a wiring layer 7032, and an OS transistor layer 7033. The OS transistor layer 7031 is connected to the OS transistor layer 7033 through the wiring layer 7032. Another OS transistor layer can also be provided on the OS transistor layer 7033 through another wiring layer. Since a plurality of OS transistor layers can be provided in a laminated manner, miniaturization of the circuit portion 7003B is facilitated.

[0129] In FIG. 8A and 8B In the IC 7000A, 7000B, a QFP (Quad Flat Package) is used as the package, but the manner of packaging is not limited to this.

[0130] The structure, method, and the like shown in the present embodiment can be implemented in combination with the structure, method, and the like shown in the other embodiments as appropriate.

[0131] (Embodiment 2)

[0132] The structure of a semiconductor device of one mode of the present application that is different from the semiconductor device described in Embodiment 1 is described.

[0133] FIG. 9Ais a block diagram of a semiconductor device of this embodiment. The semiconductor device 100A described in this embodiment can be roughly divided into a signal generation circuit 101 and a signal processing circuit 201.

[0134] Note that a semiconductor device in this specification and the like means all devices that can function by utilizing semiconductor characteristics. Thus, the signal generation circuit 101 and the signal processing circuit 201 are each referred to as a semiconductor device or the whole is referred to as a semiconductor device.

[0135] The signal generation circuit 101 has a function of outputting an input signal and an inverted input signal from a terminal D and a terminal Db. The signal generation circuit 101 includes a circuit (denoted as Si / Cir. in the drawing) formed of an Si transistor. The signal generation circuit 101 can be formed by appropriately designing using a sequential circuit and a combination circuit of a CMOS circuit.

[0136] The signal processing circuit 201 includes a circuit (denoted as OS / Cir. in the drawing) formed of an OS transistor. The signal processing circuit 201 includes a sequential circuit and a combination circuit. As one example, the combination circuit can be an inverter circuit (also referred to as a NOT circuit) or a logic AND circuit (AND circuit), or the like. The sequential circuit can be a flip-flop circuit or a counter circuit, or the like. The signal processing circuit 201 has a function of processing an input signal and an inverted input signal with an internal circuit and outputting the processed signals as an output signal and an inverted output signal from a terminal Q and a terminal Qb.

[0137] FIG. 9B is a circuit diagram showing one example of a circuit of the signal processing circuit 201. FIG. 9B The signal processing circuit 201 illustrated in the drawing has a circuit structure in which a plurality of logic circuits 202 (denoted as Seq. in the drawing) serving as sequential circuits and a plurality of logic circuits 102 (denoted as Comb. in the drawing) serving as combination circuits are combined.

[0138] The logic circuit 202 is a two-wire sequential circuit formed of an OS transistor. The OS transistor is different from an Si transistor in that the electrical characteristics thereof are less likely to vary in a high-temperature environment. Thus, the logic circuit 202 can operate with high reliability in a high-temperature environment.

[0139] FIG. 9C is a circuit diagram showing a specific circuit structure of the logic circuit 202. FIG. 9C The logic circuit 202 illustrated in the drawing is a two-wire flip-flop circuit including a logic circuit serving as an inverter circuit.

[0140] FIG. 9C The logic circuit 202 illustrated in the drawing includes a switching circuit 203 controlled to be turned on or off in accordance with a clock signal CLK or an inverted clock signal CLKb and a logic circuit 102 serving as an inverter circuit.

[0141] in addition, FIG. 9C The logic circuit 102 shown is as follows FIG. 2A to FIG. 2C The two-wire inverter circuit is shown in the illustration. FIG. 10A Showing with FIG. 2C The same two-wire circuit symbol is used. Logic circuit 102 is connected to wiring VDHL, which is provided with a high power supply potential VDH; wiring VDDL, which is provided with a high power supply potential VDD; and wiring VSSL, which is provided with a low power supply potential VSS. Therefore, FIG. 2C and FIG. 10A The symbol for the circuit can also be like FIG. 10B The circuit symbols shown are represented as indicated. Note that sometimes they are omitted. FIG. 10B The additional wiring name.

[0142] FIG. 10C It is possible to FIG. 6A The circuit diagram shown in the illustration illustrates the specific circuit structure of logic circuit 102. FIG. 10C The logic circuit 102 shown includes transistors 121 to 128. Additionally, FIG. 10C The diagram shows wiring VDHL, which is provided with a high power supply potential VDH; wiring VDDL, which is provided with a high power supply potential VDD; and wiring VSSL, which is provided with a low power supply potential VSS. Furthermore, the high power supply potential VDH is a higher potential than the high power supply potential VDD. FIG. 10C The nodes of the gate and back gate of transistor 122 are denoted as node P. The nodes of the gate and back gate of transistor 124 are denoted as node PB.

[0143] One of the gate and back gate of transistor 121 is connected to the terminal IN where the input signal is provided. One of the source and drain of transistor 121 is connected to wiring VDHL. The other of the source and drain of transistor 121 is connected to the gate and back gate of transistor 122. The other of the gate and back gate of transistor 121 is connected to the gate and back gate of transistor 122.

[0144] Transistor 121 has the following function: it turns on or off according to the potential applied to its gate, thereby controlling whether the potentials of the gate and back gate of transistor 122 are changed to the potential VDH. Transistor 121 has the function of controlling whether the transistor is normally on or normally off according to the potential applied to the back gate. Transistor 121 is also referred to as the first transistor.

[0145] One of the source and drain of transistor 122 is connected to wiring VDDL. The other of the source and drain of transistor 122 is connected to terminal OUTB.

[0146] The transistor 122 has a function of controlling whether or not the potential of the gate and the back gate becomes an on or off state in accordance with the potential applied to the gate, and thereby controls whether or not the terminal OUTB has a high level potential according to the potential VDD. The transistor 122 is also referred to as a second transistor.

[0147] One of the gate and the back gate of the transistor 123 is connected to the terminal INB to which the inverted input signal is supplied. One of the source and the drain of the transistor 123 is connected to the wiring VDHL. The other of the source and the drain of the transistor 123 is connected to the gate and the back gate of the transistor 124. The other of the gate and the back gate of the transistor 123 is connected to the gate and the back gate of the transistor 124.

[0148] The transistor 123 has a function of controlling whether or not the potential of the gate and the back gate becomes an on or off state in accordance with the potential applied to the gate, and thereby controls whether or not the potential of the gate and the back gate of the transistor 124 becomes a potential according to the potential VDH. The transistor 123 has a function of controlling the transistor to be always on or always off in accordance with the potential applied to the back gate. The transistor 123 is also referred to as a third transistor.

[0149] One of the source and the drain of the transistor 124 is connected to the wiring VDDL. The other of the source and the drain of the transistor 124 is connected to the terminal OUT.

[0150] The transistor 124 has a function of controlling whether or not the potential of the gate and the back gate becomes an on or off state in accordance with the potential applied to the gate and the back gate, and thereby controls whether or not the terminal OUT has a high level potential according to the potential VDD. The transistor 124 is also referred to as a fourth transistor.

[0151] The gate and the back gate of the transistor 125 are connected to the terminal IN to which the input signal is supplied. Alternatively, either of the gate and the back gate of the transistor 125 can be connected to the terminal IN. One of the source and the drain of the transistor 125 is connected to the gate and the back gate of the transistor 124. The other of the source and the drain of the transistor 125 is connected to the wiring VSSL.

[0152] The transistor 125 has a function of controlling whether or not the potential of the gate and the back gate becomes an on or off state in accordance with the potential of the terminal IN applied to the gate and the back gate, and thereby controls whether or not the potential of the gate and the back gate of the transistor 124 becomes a low level potential according to the potential VSS. The transistor 125 is also referred to as a fifth transistor.

[0153] The gate and the back gate of the transistor 126 are connected to the terminal IN to which the input signal is supplied. Alternatively, either of the gate and the back gate of the transistor 126 can be connected to the terminal IN. One of the source and the drain of the transistor 126 is connected to the terminal OUT from which the output signal is output. The other of the source and the drain of the transistor 126 is connected to the wiring VSSL.

[0154] The transistor 126 has a function of turning on or off in accordance with the potential of the terminal IN applied to the gate and the back gate becoming a low-level potential according to the potential VSS. The transistor 126 is also referred to as a sixth transistor.

[0155] The gate and the back gate of the transistor 127 are connected to the terminal INB to which the inverted input signal is supplied. Alternatively, either of the gate and the back gate of the transistor 127 can be connected to the terminal INB. One of the source and the drain of the transistor 127 is connected to the gate and the back gate of the transistor 122. The other of the source and the drain of the transistor 127 is connected to the wiring VSSL.

[0156] The transistor 127 has a function of turning on or off in accordance with the potential of the terminal INB applied to the gate and the back gate, the potential of the gate and the back gate of the transistor 122 becoming a low-level potential according to the potential VSS. The transistor 127 is also referred to as a seventh transistor.

[0157] The gate and the back gate of the transistor 128 are connected to the terminal INB to which the inverted input signal is supplied. Alternatively, either of the gate and the back gate of the transistor 128 can be connected to the terminal INB. One of the source and the drain of the transistor 128 is connected to the terminal OUTB to which the inverted output signal is output. The other of the source and the drain of the transistor 128 is connected to the wiring VSSL.

[0158] The transistor 128 has a function of turning on or off in accordance with the potential of the terminal INB applied to the gate and the back gate, the terminal OUTB having a low-level potential according to the potential VSS. The transistor 128 is also referred to as an eighth transistor.

[0159] By employing this configuration, it is possible to switch the potential applied to the back gate of the transistor as FIG. 3A , the potential applied to the back gate of the transistor as 3B illustrated.

[0160] Next, the operation of the logic circuit 102 shown in FIG. 10D will be described. FIG. 10C The operation of the logic circuit 102 shown in FIG. 10D will be described. FIG. 10C The timing chart for explaining the operation of the logic circuit 102 shown in FIG. 10D will be described. FIG. 6B The timing chart for explaining the operation of the logic circuit 102 shown in is the same as the timing chart described above.

[0161] FIG. 10CIn the timing chart shown, at times Tll to T12 and times T13 to T14, the input signal supplied to the terminal IN is made high, and the inverted input signal supplied to the terminal INB is made low. The transistor 121 becomes always on, and the transistors 125 and 126 become on. The transistor 123 becomes always off, and the transistors 127 and 128 become off. The node P becomes a high-level potential according to the potential VDH, and the transistor 122 becomes on. The node PB becomes a low-level potential according to the potential VSS, and the transistor 124 becomes off. The terminal OUT has a low-level potential according to the potential VSS. The terminal OUTB has a high-level potential according to the potential VDD.

[0162] The back gate of the transistor 121 is supplied with a high-level potential, and the back gate of the transistor 123 is supplied with a low-level potential. As a result, the transistor 121 becomes an always on transistor, and the transistor 123 becomes an always off transistor. The transistor 121 can be used as an always on transistor, and thus the amount of current flowing through the gate and the back gate of the transistor 122 can be increased. In addition, the transistor 123 can be used as an always off transistor, and thus the through current between the wiring VDHL and the wiring VSSL can be effectively reduced.

[0163] In addition, FIG. 10C In the structure of the node P can be made a potential according to the potential VDH which is higher than the potential VDD. Thus, the voltage applied between the gate and the source of the transistor 122 can be increased, and thus the voltage drop corresponding to the size of the threshold voltage can be reduced, and the potential of the terminal OUTB can be made the potential VDD more accurately.

[0164] In FIG. 10D In the timing chart shown, at times Tll to T12 and times T13 to T14, the input signal supplied to the terminal IN is made high, and the inverted input signal supplied to the terminal INB is made low. The transistor 121 becomes always on, and the transistors 125 and 126 become on. The transistor 123 becomes always off, and the transistors 127 and 128 become off. The node P becomes a high-level potential according to the potential VDH, and the transistor 122 becomes on. The node PB becomes a low-level potential according to the potential VSS, and the transistor 124 becomes off. The terminal OUT has a low-level potential according to the potential VSS. The terminal OUTB has a high-level potential according to the potential VDD.

[0165] The back gate of the transistor 121 is supplied with a low potential, and the back gate of the transistor 123 is supplied with a high potential. As a result, the transistor 121 becomes a normally-off transistor, and the transistor 123 becomes a normally-on transistor. The transistor 121 can function as a normally-off transistor, and thus the through current between the wiring VDHL and the wiring VSSL can be reduced effectively. In addition, the transistor 123 can function as a normally-on transistor, and thus the amount of current flowing through the gate and the back gate of the transistor 124 can be increased.

[0166] In addition, FIG. 10C In the structure, the node PB can be supplied with a potential higher than the potential VDD. Thus, the voltage applied between the gate and the source of the transistor 124 can be increased, and thus the voltage drop corresponding to the threshold voltage can be reduced, and the potential of the terminal OUTB can be made to be the potential VDD more accurately.

[0167] FIG. 9C The switch circuit 203 illustrated in FIG. 8 includes a two-wire switch. Specifically, two transistors which control the on or off are provided between the terminal IN and the terminal OUT and between the terminal INB and the terminal OUTB. FIG. 11A A symbol of a circuit symbol of a two-wire switch which controls the on or off using a clock signal CLK is illustrated.

[0168] FIG. 11A The switch circuit 203 illustrated in FIG. 8 can have a structure as illustrated in FIG. 11B the switch circuit 203A, that is, a structure in which the on or off is controlled by connecting a wiring which supplies a clock signal CLK to the gate of each transistor.

[0169] In addition, as another structure, the structure illustrated in FIG. 11C FIG. 9 can be employed. FIG. 11C The switch circuit 203B illustrated in FIG. 10 can have a structure in which, in addition to a wiring which supplies a clock signal CLK, a wiring which supplies a signal BG to the back gate is provided separately, and the on or off is controlled in correspondence with the signals supplied to the gate and the back gate. The signal BG is a signal which supplies a potential for controlling the threshold voltage of the transistor. By employing this structure, the threshold voltage of the transistor can be controlled while the on or off of the transistor is controlled.

[0170] In addition, as another structure, the structure illustrated in FIG. 11D FIG. 11 can be employed. FIG. 11D The switch circuit 203C illustrated in FIG. 12 can have a structure in which the on or off is controlled by connecting a wiring which supplies a clock signal CLK to the gate and the back gate of each transistor. By employing this structure, the transistor can have excellent switching characteristics.

[0171] By employing the above-described structure, the semiconductor device having the logic circuit composed of the OS transistor can achieve low power consumption while achieving operation with excellent reliability. Further, the drop in the signal voltage to be output can be suppressed.

[0172] Next, a structure different from the above-described structure is described.

[0173] FIG. 12A is a circuit diagram of a logic circuit to which the structure of FIG. 10B is applied. FIG. 12A The logic circuit 102E shown in FIG. 10 includes transistors 151 to 165. In addition, FIG. 12A A wiring VDHL to which a high power supply potential VDH is supplied, a wiring VDDL to which a high power supply potential VDD is supplied, and a wiring VSSL to which a low power supply potential VSS is supplied are shown. Terminals IN1, IN1B, IN2, and terminals IN2B are terminals to which input signals are supplied. Terminals OUT and OUTB are terminals to which output signals are supplied. From the terminal OUT, an output signal of NAND (NOR of inverted input signals) corresponding to the input signals can be obtained, and from the terminal OUTB, an output signal of NAND (logical AND of inverted input signals) corresponding to the input signals can be obtained. In addition, the function of the logic circuit can be switched by exchanging the signals input to the respective terminals. FIG. 12A The truth table of the logic circuit shown in FIG. 10 is the same as Table 1 described in Embodiment 1.

[0174] FIG. 12A The logic circuit 102D shown in FIG. 11 shows a two-wire NAND circuit. FIG. 12B A symbol showing a circuit symbol of the two-wire NAND circuit is shown. Note that the wiring names added in FIG. 11 are sometimes omitted. FIG. 12B

[0175] By employing the above-described combination circuit, a complex circuit such as a counter, a serial-parallel converter, a processor, or the like can be realized. Since the above-described circuit can be composed of the OS transistor, a good switching characteristic can be maintained even in a high-temperature environment. In addition, the through current can be reduced to lower power consumption, and a drop in voltage equivalent to the size of the threshold voltage or the like can be suppressed.

[0176] In addition, as another structure example, FIG. 13A A circuit diagram of a logic circuit 202A capable of holding data even when the supply of a power supply voltage is stopped and capable of power gating is shown. The logic circuit 202A includes, in addition to the logic circuit 102 and the switching circuit 203, a logic circuit 102E to which a reset signal RST and an inverted reset signal RSTb are input and a switching circuit 203D to which a power gating signal PG and a signal BG are supplied.

[0177] ​The switching circuit 203D is controlled to turn on or off based on the signal PG. The signal PG is used to hold data during power gating. The transistors constituting the switching circuit 203D, like other logic circuits, are OS transistors. OS transistors have extremely low off-state current. Therefore, by turning off the transistors in the switching circuit 203D, the switching circuit can... FIG. 13A The nodes SN and SNb shown maintain the charge of the data supplied to the logic circuit 202A.

[0178] FIG. 13A The logic circuit 202A shown is an asynchronous reset logic circuit and is used as a flip-flop circuit with power gating function. FIG. 13B Show FIG. 13A The symbol for the circuit.

[0179] Next, refer to FIG. 14 illustrate FIG. 13A The operation of the logic circuit 202A shown. FIG. 14 Shown for illustration FIG. 13A The timing diagram for the operation of logic circuit 202A is shown. FIG. 14 The diagram is divided into four phases: Run (signal processing), BK (data backup), PG (power gating), and Recovery (data recovery).

[0180] exist FIG. 14 In the timing diagram shown, from time T21 to T22, the system transitions from the signal processing state to the data backup state. During this time, signal BG is set low, causing the transistor in switching circuit 203D to be normally off. Furthermore, from time T22 to T23, signal PG is set low. The capacitors connected to nodes SN and SNb retain the charge corresponding to the data.

[0181] From time T23 to T24, voltages VDD and VDH are set to low levels, thereby preventing current from flowing between the power lines. During this period, the capacitors connected to nodes SN and SNb retain the charge corresponding to the data. Because signal BG is low, the OS transistor is normally off. Therefore, the capacitors connected to nodes SN and SNb continue to retain the charge corresponding to the data.

[0182] Between times T24 and T25, the system transitions from the power-gated state to the data recovery state. At this time, the potentials of the wiring supplied with low-level voltages VDD and VDH are restored to their original values. Since signal BG is low, the OS transistor is normally off. Therefore, the capacitors connected to nodes SN and SNb continue to retain the charge corresponding to the data.

[0183] At time T25 to T26, the clock signal CLK is made high. Thereby, a signal corresponding to the charge of the data held by the nodes SN and SNb is output from the logic circuit 102 connected to the nodes SN and SNb to the logic circuit 102E.

[0184] At time T26 to T27, the clock signal CLK is made low and the signals BG and PG are made high. Thereby, the state before the data was held in the nodes SN and SNb is restored. Then, after time T27, the clock signal CLK and the inverted clock signal CLKb are again supplied to perform signal processing.

[0185] The logic circuit 202A includes the logic circuit 102 and the logic circuit 102E described above, and the like. Thereby, the through current between the wiring VDHL and the wiring VSSL can be effectively reduced.

[0186] Note that, FIG. 13A the structure described in FIG. 15A can also be implemented in the circuit diagram illustrated in FIG. 13A . That is, the structure described in FIG. 15B can be implemented in a case where a structure in which the wiring for transmitting the inverted input signal and the inverted output signal is omitted is employed, like the logic circuit 202B. FIG. 13A , and the like. Similarly, the structure described in can be implemented in a case where a structure in which a NOR circuit is used instead of a NAND circuit is employed, like the circuit diagram of the logic circuit 202C.

[0187] FIG. 16 Further, as another structural example, FIG. 16 the logic circuit 202D illustrated in is a circuit diagram of a structure example of a 2-bit counter (with an asynchronous reset function) to which the logic circuit described above is applied.

[0188] The circuit structure illustrated in can be implemented by combining the logic circuits with different functions described above.

[0189] (Embodiment 3)

[0190] A structure example of an OS transistor which can be used for the semiconductor device described in the above embodiments is described in this embodiment.

[0191] <Structure Example of Transistor>

[0192] FIG. 17A FIG. 17C is a cross-sectional view of a transistor 500 which is an example of an OS transistor. FIG. 17A is a cross-sectional view in the channel length direction of the transistor 500,FIG. 17B is a cross-sectional view of the channel width direction of the transistor 500.

[0193] The transistor 500 is an OS transistor including a metal oxide in a channel formation region. The transistor 500 can have a good switching property even in a high-temperature environment at 200 °C or higher, and thus a semiconductor device with high reliability in a high-temperature environment can be achieved. Further, reduction in off-state current can be achieved, and thus a semiconductor device capable of low power consumption in a high-temperature environment can be achieved.

[0194] In the cross-sectional view illustrated in FIG. 5A, the insulator 512, the insulator 514, and the insulator 516 are provided in this order. FIG. 17A and FIG. 17B In the cross-sectional view illustrated in FIG. 5A, the insulator 512, the insulator 514, and the insulator 516 are provided in this order. It is preferable that any of the insulator 512, the insulator 514, and the insulator 516 use a substance having a barrier property against oxygen and hydrogen.

[0195] For example, the insulator 514 preferably uses a film having a barrier property, which does not allow hydrogen, impurities, or the like to diffuse from a lower substrate or the like into a region where the transistor 500 is provided.

[0196] As one example of a film having a barrier property against hydrogen, silicon nitride formed by a CVD method can be used. In addition, as a film having a barrier property against hydrogen, for example, it is preferable that a metal oxide such as aluminum oxide, hafnium oxide, or tantalum oxide be used as the insulator 514.

[0197] In particular, aluminum oxide has a high barrier effect of preventing penetration of oxygen, hydrogen, moisture, and the like which cause variation in electrical characteristics of the transistor. Thus, aluminum oxide can prevent entry of hydrogen, moisture, and the like into the transistor 500 in a manufacturing process of the transistor and after the manufacturing process. Further, aluminum oxide can suppress release of oxygen from the oxide included in the transistor 500. Thus, aluminum oxide is suitable for a protective film of the transistor 500.

[0198] For example, as the insulator 512 and the insulator 516, by forming an interlayer film of a material with a low dielectric constant, parasitic capacitance generated between wirings can be reduced. For example, as the insulator 512 and the insulator 516, a silicon oxide film, a silicon oxynitride film, or the like can be used.

[0199] The transistor 500 is provided over the insulator 516.

[0200] As FIG. 17A and FIG. 17BAs shown in FIG. 5A, the transistor 500 includes an insulator 516, an insulator 520 provided over the insulator 516, an insulator 522 provided over the insulator 520, an insulator 524 provided over the insulator 522, an oxide 530a provided over the insulator 524, an oxide 530b provided over the oxide 530a, a conductive body 542a and a conductive body 542b provided over the oxide 530b and separated from each other, an insulator 580 provided over the conductive body 542a and the conductive body 542b and formed with an opening overlapping with the conductive body 542a and the conductive body 542b, a conductive body 560 provided in the opening, an insulator 550 provided between the oxide 530b, the conductive body 542a, the conductive body 542b, the insulator 580, and the conductive body 560, and an oxide 530c provided between the oxide 530b, the conductive body 542a, the conductive body 542b, the insulator 580, and the insulator 550.

[0201] In addition, as shown in FIG. 5B, an insulator 544 is preferably provided between the oxide 530a, the oxide 530b, the conductive body 542a, the conductive body 542b, and the insulator 580. FIG. 17A and FIG. 17B In addition, as shown in FIG. 5B, an insulator 544 is preferably provided between the oxide 530a, the oxide 530b, the conductive body 542a, the conductive body 542b, and the insulator 580. FIG. 17A and FIG. 17B In addition, as shown in FIG. 5B, an insulator 544 is preferably provided between the oxide 530a, the oxide 530b, the conductive body 542a, the conductive body 542b, and the insulator 580. FIG. 17A and FIG. 17B In addition, as shown in FIG. 5B, an insulator 544 is preferably provided between the oxide 530a, the oxide 530b, the conductive body 542a, the conductive body 542b, and the insulator 580.

[0202] Note that the oxide 530a, the oxide 530b, and the oxide 530c are collectively referred to as an oxide 530 in some cases below. In addition, the conductive body 542a and the conductive body 542b are collectively referred to as a conductive body 542 in some cases below.

[0203] In the transistor 500, three layers of the oxide 530a, the oxide 530b, and the oxide 530c are stacked in a region where a channel is formed and its vicinity, but the present application is not limited to this. 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-layer structure of four or more layers can be provided. In the transistor 500, the conductive body 560 has a two-layer structure, but the present application is not limited to this. For example, the conductive body 560 can have a single-layer structure or a stacked-layer structure of three or more layers. Note that FIG. 17A , FIG. 17A The structure of the transistor 500 shown in FIGS. 5A and 5B is just an example and is not limited to the above structure, and an appropriate transistor can be used depending on the circuit structure or the driving method.

[0204] Here, the conductive body 560 is used as a gate electrode of the transistor, and the conductive bodies 542a and 542b are used as source or drain electrodes. As described above, the conductive body 560 is buried in the opening of the insulator 580 and in the region between the conductive bodies 542a and 542b. The arrangement of the conductive body 560, the conductive body 542a, and the conductive body 542b with respect to the opening of the insulator 580 is self-aligned. In other words, in the transistor 500, the gate electrode can be arranged self-aligned between the source electrode and the drain electrode. Thus, the conductive body 560 can be formed without providing a margin for alignment, so that reduction in the area occupied by the transistor 500 can be achieved. Thus, miniaturization and high integration of the semiconductor device can be achieved.

[0205] Further, the conductive body 560 is formed self-aligned in the region between the conductive bodies 542a and 542b, so that the conductive body 560 does not include a region overlapping with the conductive bodies 542a and 542b. Thus, the parasitic capacitance formed between the conductive body 560 and the conductive bodies 542a and 542b can be reduced. Therefore, the switching speed of the transistor 500 can be increased, so that the transistor 500 can have high frequency characteristics.

[0206] The insulator 550 has a function of a gate insulating film.

[0207] Here, the insulator 524 in contact with the oxide 530 preferably uses an insulator containing oxygen in excess of the stoichiometric composition. In other words, a region of excess oxygen is preferably formed in the insulator 524. By providing the above insulator containing excess oxygen in contact with the oxide 530, oxygen vacancies in the oxide 530 can be reduced, so that the reliability of the transistor 500 can be improved.

[0208] Specifically, as the insulator having a region of excess oxygen, an oxide material from which a part of oxygen is released by heating is preferably used. The oxide from which oxygen is released by heating means an oxide in which the amount of oxygen released as oxygen atoms in TDS (Thermal Desorption Spectroscopy) analysis is 1.0 x 10 18 atoms / cm 3 or more, preferably 1.0 x 10 19 atoms / cm 3 or more, further preferably 2.0 x 10 19 atoms / cm 3 or more, or 3.0 x 10 20 atoms / cm 3 or more. Note that the surface temperature of the film at the time of the above 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.

[0209] When the insulator 524 has an excess oxygen region, the insulator 522 preferably has a function of inhibiting diffusion of oxygen (e.g., oxygen atoms, oxygen molecules, or the like) (not easily allowing the above-described oxygen to pass through).

[0210] When the insulator 522 has a function of inhibiting diffusion of oxygen or impurities, oxygen contained in the oxide 530 does not diffuse to the insulator 520 side, and thus is preferable.

[0211] As the insulator 522, for example, a single layer or a stack of insulators containing aluminum oxide, hafnium oxide, tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO3), or (Ba, Sr) TiO3(BST), or the like, so-called high-k materials, is preferably used. When miniaturization and high integration of transistors are performed, a problem such as a leakage current occurs due to thinning of a gate insulator. By using a high-k material as an insulator used as a gate insulator, the gate potential at the time of transistor operation can be reduced while the physical thickness is maintained.

[0212] In particular, an insulator containing an oxide of one or both of aluminum and hafnium, which is an insulating material having a function of inhibiting diffusion of impurities and oxygen or the like (not easily allowing the above-described oxygen to pass through), is preferably used. As the insulator containing an oxide of one or both of aluminum and hafnium, aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), or the like is preferably used. When the insulator 522 is formed using such a material, the insulator 522 is used as a layer for inhibiting release of oxygen from the oxide 530 or entry of impurities such as hydrogen from the surrounding portion of the transistor 500 into the oxide 530.

[0213] Alternatively, for example, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, zirconium oxide can be added to the above-described insulator. Further, the above-described insulator can be subjected to a nitriding treatment. Silicon oxide, silicon oxynitride, or silicon nitride can be further stacked on the above-described insulator.

[0214] The insulator 520 preferably has thermal stability. For example, silicon oxide and silicon oxynitride have thermal stability, and thus are preferable. Further, by combining an insulator of a high-k material with silicon oxide or silicon oxynitride, an insulator 520 having a stacked structure with high relative dielectric constant and thermal stability can be formed.

[0215] The insulator 520, the insulator 522, and the insulator 524 can have a stacked structure of two or more layers. At this time, the stacked structure is not limited to one formed using the same material, and can be one formed using different materials.

[0216] In transistor 500, the metal oxide to be used as an oxide semiconductor is preferably used in oxide 530, which includes the channel formation region. For example, In-M-Zn oxide (where element M is selected from one or more of aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) is preferably used as oxide 530. In-Ga oxide and In-Zn oxide may also be used as oxide 530.

[0217] As the metal oxide used as the channel formation region in oxide 530, it is preferable to use a metal oxide with a band gap of 2 eV or more, and more preferably 2.5 eV or more. In this way, by using a metal oxide with a wider band gap, the off-state current of the transistor can be reduced.

[0218] In oxide 530, when oxide 530a is disposed below oxide 530b, impurities can be prevented from diffusing from the structure formed below oxide 530a to oxide 530b. When oxide 530c is disposed above oxide 530b, impurities can be prevented from diffusing from the structure formed above oxide 530c to oxide 530b.

[0219] Furthermore, oxide 530 preferably has a stacked structure of oxides having different atomic ratios of each metal atom. Specifically, the atomic ratio of element M in the constituent elements of the metal oxide used for oxide 530a is preferably greater than that in the metal oxide used for oxide 530b. Additionally, the atomic ratio of element M relative to In in the metal oxide used for oxide 530a is preferably greater than that in the metal oxide used for oxide 530b. Furthermore, the atomic ratio of In relative to element M in the metal oxide used for oxide 530b is preferably greater than that in the metal oxide used for oxide 530a. Additionally, oxide 530c can use a metal oxide that can be used for oxide 530a or oxide 530b.

[0220] Preferably, the conduction band bottom energies of oxides 530a and 530c are higher than those of oxide 530b. In other words, the electron affinity of oxides 530a and 530c is preferably less than that of oxide 530b.

[0221] Here, in the junction of the oxide 530a, the oxide 530b, and the oxide 530c, the energy level of the conduction band bottom gently changes. In other words, the above case can also be expressed as the energy level of the conduction band bottom of the junction of the oxide 530a, the oxide 530b, and the oxide 530c continuously changes or continuously joins. For this reason, it is preferable to reduce the density of defect states of the mixed layer formed at the interface of the oxide 530a and the oxide 530b and the interface of the oxide 530b and the oxide 530c.

[0222] Specifically, by making the oxide 530a and the oxide 530b and the oxide 530b and the oxide 530c contain a common element (as a main component) in addition to oxygen, a mixed layer with a low density of defect states can be formed. For example, in the case where the oxide 530b is an In-Ga-Zn oxide, as the oxide 530a and the oxide 530c, an In-Ga-Zn oxide, a Ga-Zn oxide, gallium oxide, or the like is preferably used.

[0223] At this time, the main path of the carriers is the oxide 530b. By making the oxide 530a and the oxide 530c have the above structure, the density of defect states of the interface of the oxide 530a and the oxide 530b and the interface of the oxide 530b and the oxide 530c can be reduced. Thus, the influence of the interface scattering on the conduction of the carriers is reduced, and the on-state current of the transistor 500 can be increased.

[0224] The conductive body 542 (the conductive body 542a and the conductive body 542b) used as the source electrode and the drain electrode is provided over the oxide 530b. As the conductive body 542, 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 metal element, an alloy containing a plurality of the above metal elements, or the like is preferably used. For example, 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 is preferably used. Note that tantalum nitride, titanium nitride, a nitride containing titanium and aluminum, a nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, an oxide containing strontium and ruthenium, and an oxide containing lanthanum and nickel are a conductive material which is not easily oxidized or a material which maintains conductivity even when oxygen is absorbed, and thus is preferable.

[0225] In addition, as shown in FIG. 5B, a region 543 (a region 543a and a region 543b) is formed as a low-resistance region at the interface between the oxide 530 and the conductive body 542 and in its vicinity. FIG. 17B At this time, the region 543a is used as one of the source region and the drain region, and the region 543b is used as the other of the source region and the drain region. Furthermore, a channel formation region is formed in a region sandwiched between the region 543a and the region 543b.

[0226] By forming the above-described conductive body 542 in contact with the oxide 530, the oxygen concentration of the region 543 is sometimes reduced. In addition, a metal compound layer including a component of the metal contained in the conductive body 542 and the oxide 530 is sometimes formed in the region 543. In this case, the carrier density of the region 543 increases, and the region 543 becomes a low-resistance region.

[0227] The insulator 544 is provided so as to cover the conductive body 542, and oxidation of the conductive body 542 is suppressed. At this time, the insulator 544 can also be provided so as to cover the side surface of the oxide 530 and be in contact with the insulator 524.

[0228] As the insulator 544, a metal oxide including one or two or more selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, and magnesium, and the like can be used.

[0229] In particular, as the insulator 544, aluminum oxide, hafnium oxide, an oxide including aluminum and hafnium (hafnium aluminate), and the like, which are insulators including one or both of aluminum and hafnium oxides, are preferably used. In particular, hafnium aluminate has higher heat resistance than hafnium oxide film. Thus, it is not easily crystallized in heat treatment in a later process, and is thus preferable. In addition, in the case where the conductive body 542 is a material having oxidation resistance or absorbs oxygen without a significant decrease in conductivity, the insulator 544 does not necessarily need to be provided. The insulator 544 can be appropriately designed depending on the transistor characteristics required.

[0230] The insulator 550 is used as a gate insulator. The insulator 550 is preferably arranged so as to be in contact with the inner side (top surface and side surface) of the oxide 530c. The insulator 550 is preferably formed using an insulator from which oxygen is released by heating. For example, an oxide film in which the amount of oxygen released as oxygen atoms in thermal desorption spectroscopy (TDS analysis) is 1.0 x 10 18 atoms / cm 3 The above is preferably 1.0 x 10 19 atoms / cm 3 The above is further preferably 2.0 x 10 19 atoms / cm 3 The above is 3.0 x 10 20 atoms / cm 3 or more. In addition, the surface temperature of the film at the time of the above-described TDS analysis is preferably in the range of 100 °C or higher and 700 °C or lower.

[0231] Specifically, silicon oxide containing excess oxygen, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide added with fluorine, silicon oxide added with carbon, silicon oxide added with carbon and nitrogen, silicon oxide having a void, or the like can be used. In particular, silicon oxide and silicon oxynitride have thermal stability, and thus are preferable.

[0232] By providing the insulator 550 that releases oxygen by heating in contact with the top surface of the oxide 530c, oxygen can be efficiently supplied from the insulator 550 to the channel formation region of the oxide 530b through the oxide 530c. Further, as with the insulator 524, it is preferable to reduce the concentration of impurities such as water or hydrogen in the insulator 550. The thickness of the insulator 550 is preferably greater than or equal to 1 nm and less than or equal to 20 nm.

[0233] In addition, in order to efficiently supply excess oxygen contained in the insulator 550 to the oxide 530, a metal oxide can be provided between the insulator 550 and the conductor 560. The metal oxide preferably inhibits diffusion of oxygen from the insulator 550 to the conductor 560. By providing the metal oxide that inhibits diffusion of oxygen, diffusion of excess oxygen from the insulator 550 to the conductor 560 is inhibited. In other words, reduction of excess oxygen supplied to the oxide 530 can be inhibited. In addition, oxidation of the conductor 560 due to excess oxygen can be inhibited. As the metal oxide, a material that can be used for the insulator 544 can be used.

[0234] In FIG. 18A and FIG. 18B the conductor 560 used as a gate electrode has a two-layer structure, but can have a single-layer structure or a stacked-layer structure of three or more layers.

[0235] As the conductor 560a, a conductive material having a function of inhibiting diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (N2O, NO, NO2, or the like), copper atoms, and the like is preferably used. In addition, a conductive material having a function of inhibiting diffusion of oxygen (e.g., at least one of oxygen atoms, oxygen molecules, and the like) is preferably used. By providing the conductor 560a with a function of inhibiting diffusion of oxygen, reduction in conductivity due to oxidation of the conductor 560b caused by oxygen contained in the insulator 550 can be inhibited. As the conductive material having a function of inhibiting diffusion of oxygen, for example, tantalum, tantalum nitride, ruthenium, or ruthenium oxide, or the like is preferably used.

[0236] As the conductor 560b, a conductive material mainly containing tungsten, copper, or aluminum is preferably used. Since the conductor 560b is also used as a wiring, a conductor with high conductivity is preferably used. For example, a conductive material mainly containing tungsten, copper, or aluminum can be used. The conductor 560b can also have a stacked-layer structure, for example, a stacked-layer structure of titanium, titanium nitride, and the above conductive material can be employed.

[0237] The insulator 580 is preferably provided on the conductor 542 with the insulator 544 interposed therebetween. The insulator 580 preferably has an excess-oxygen region. For example, the insulator 580 preferably contains silicon oxide, 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, silicon oxide having a void, or resin. In particular, silicon oxide and silicon oxynitride have heat resistance, and are thus preferable. In particular, silicon oxide and silicon oxide having a void easily form an excess-oxygen region in a subsequent step, and are thus preferable.

[0238] The insulator 580 preferably has an excess-oxygen region. By providing the insulator 580 which releases oxygen by heating in contact with the oxide 530c, oxygen in the insulator 580 can be efficiently supplied to the oxide 530 via the oxide 530c. In addition, it is preferable to reduce the concentration of impurities such as water or hydrogen in the insulator 580.

[0239] The opening of the insulator 580 is formed so as to overlap with the region between the conductor 542a and the conductor 542b. Thus, the conductor 560 is filled in the opening of the insulator 580 and in the region between the conductor 542a and the conductor 542b.

[0240] When miniaturization of a semiconductor device is performed, it is necessary to shorten the gate length, but it is necessary to prevent a decrease in the conductivity of the conductor 560. For this reason, in the case where the thickness of the conductor 560 is increased, the conductor 560 can have a shape with a high aspect ratio. In this embodiment, since the conductor 560 is filled in the opening of the insulator 580, even if the conductor 560 has a shape with a high aspect ratio, collapse of the conductor 560 does not occur in the process.

[0241] The insulator 574 is preferably provided so as to be in contact with the top surface of the insulator 580, the top surface of the conductor 560, and the top surface of the insulator 550. By forming the insulator 574 using a sputtering method, an excess-oxygen region can be formed in the insulator 550 and the insulator 580. Thus, oxygen can be supplied from the excess-oxygen region to the oxide 530.

[0242] For example, as the insulator 574, a metal oxide containing one or two or more kinds selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, and magnesium, or the like can be used.

[0243] In particular, aluminum oxide has high barrier properties, and even a thin film of 0.5 nm or more and 3.0 nm or less can suppress diffusion of hydrogen and nitrogen. Thus, aluminum oxide formed using a sputtering method can function as a barrier film for impurities such as hydrogen while being used as an oxygen supply source.

[0244] Further, an insulator 581 used as an interlayer film is preferably provided over the insulator 574. As with the insulator 524, it is preferable to reduce the concentration of impurities such as water or hydrogen in the insulator 581.

[0245] Further, the conductive body 540a and the conductive body 540b are arranged in openings formed in the insulator 581, the insulator 574, the insulator 580, and the insulator 544. The conductive body 540a and the conductive body 540b are arranged so as to face each other with the conductive body 560 interposed therebetween. The conductive body 540a and the conductive body 540b have a function of a plug or a wiring connected to the transistor 500.

[0246] With the use of the present structure, it is possible to improve reliability while suppressing variation in electrical characteristics of a semiconductor device using a transistor including an oxide semiconductor. Furthermore, it is possible to provide a transistor including an oxide semiconductor with a large on-state current. Furthermore, it is possible to provide a transistor including an oxide semiconductor with a small off-state current. Furthermore, it is possible to provide a semiconductor device with reduced power consumption. Furthermore, it is possible to achieve miniaturization or high integration of a semiconductor device using a transistor including an oxide semiconductor.

[0247] Note that the structure of the transistor 500 of the semiconductor device described in this embodiment is not limited to the above structure. Hereinafter, a structure example of the transistor 500 will be described.

[0248] Structure Example 1 of Transistor

[0249] Structure Example 1 of Transistor FIG. 18C , FIG. 18A and FIG. 18B A structure example of the transistor 510A will be described with reference to FIGS. 1A to 1C. FIG. 18A is a top view of the transistor 510A. FIG. 18C is a cross-sectional view of a portion indicated by a dotted line L1-L2 in FIG. 18A . FIG. 18A is a cross-sectional view of a portion indicated by a dotted line W1-W2 in FIG. 18A . In the top view of FIG. 18B , a part of a component is omitted for clarity.

[0250] The transistor 510A, the insulator 511 used as an interlayer film, the insulator 512, the insulator 514, the insulator 516, the insulator 580, the insulator 582, and the insulator 584 are illustrated in FIG. 18C , FIG. 18A and FIG. 18B . Further, the conductive body 546 (the conductive body 546a and the conductive body 546b) electrically connected to the transistor 510A and used as a contact plug is illustrated.

[0251] The transistor 510A includes a conductive body 560 (the conductive body 560a and the conductive body 560b) serving as a gate electrode, an insulator 550 serving as a gate electrode, an oxide 530 (the oxide 530a, the oxide 530b, and the oxide 530c) including a region forming a channel, a conductive body 542a serving as one of a source and a drain, a conductive body 542b serving as the other of the source and the drain, and an insulator 574.

[0252] In addition, in the transistor 510A illustrated in FIG. 5A, the oxide 530c, the insulator 550, and the conductive body 560 are provided in the opening provided in the insulator 580 with the insulator 574 interposed therebetween. Further, the oxide 530c, the insulator 550, and the conductive body 560 are provided between the conductive body 542a and the conductive body 542b. FIG. 18C FIG. 18A FIG. 18B

[0253] The insulator 511 and the insulator 512 are used as interlayer films.

[0254] As the interlayer film, a single layer or a stack of insulators such as silicon oxide, silicon oxynitride, silicon nitride oxide, aluminum oxide, hafnium oxide, tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO3), or (Ba, Sr) TiO3(BST) can be used. Alternatively, for example, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, zirconium oxide can be added to these insulators. Further, these insulators can be subjected to nitridation treatment. A silicon oxide, silicon oxynitride, or silicon nitride layer can be stacked on the above insulator.

[0255] For example, the insulator 511 is preferably used as a barrier film for inhibiting entry of impurities such as water or hydrogen from the substrate side into the transistor 510A. Thus, as the insulator 511, an insulating material having a function of inhibiting diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms (not easy to allow the above impurities to pass through) is preferably used. Further, an insulating material having a function of inhibiting diffusion of oxygen (at least one of, for example, oxygen atoms, oxygen molecules, and the like) (not easy to allow the above oxygen to pass through) is preferably used. For example, aluminum oxide or silicon nitride is preferably used as the insulator 511. With this structure, diffusion of impurities such as hydrogen and water from the side closer to the substrate than the insulator 511 to the side of the transistor 510A can be inhibited.

[0256] For example, the dielectric constant of the insulator 512 is preferably lower than that of the insulator 511. By using a material with a low dielectric constant for the interlayer film, the parasitic capacitance generated between wirings can be reduced.

[0257] The conductive body 560 in the transistor 510A is sometimes used as a gate electrode.

[0258] ​​​Like the insulator 511 and the insulator 512, the insulator 514 and the insulator 516 are used as interlayer films. For example, the insulator 514 is preferably used as a barrier film for inhibiting impurities such as water or hydrogen from entering the transistor 510A from the substrate side. With this structure, diffusion of impurities such as hydrogen or water from the side closer to the substrate than the insulator 514 to the side of the transistor 510A can be inhibited. For example, the dielectric constant of the insulator 516 is preferably lower than that of the insulator 514. By using a material with a low dielectric constant for an interlayer film, the parasitic capacitance generated between wirings can be reduced.

[0259] The insulator 522 preferably has a barrier property. By making the insulator 522 have a barrier property, it can be used as a layer for inhibiting impurities such as hydrogen from entering the transistor 510A from the periphery of the transistor 510A.

[0260] As the insulator 522, for example, a single layer or a stack of insulators containing a so-called high-k material such as aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO3), or (Ba, Sr) TiO3(BST) is preferably used. When miniaturization and high integration of a transistor are performed, a problem such as a leakage current occurs due to thinning of a gate insulating film. By using a high-k material for an insulator used as a gate insulating film, the gate potential at the time of transistor operation can be reduced while the physical thickness is maintained.

[0261] For example, the insulator 521 preferably has thermal stability. For example, since silicon oxide and silicon oxynitride have thermal stability, by combining an insulator of a high-k material with the insulator 522, a stacked structure with thermal stability and a high relative dielectric constant can be formed.

[0262] The oxide 530 including a region used as a channel formation region includes the oxide 530a, the oxide 530b over the oxide 530a, and the oxide 530c over the oxide 530b. When the oxide 530a is provided under the oxide 530b, diffusion of impurities from a structure formed under the oxide 530a to the oxide 530b can be prevented. When the oxide 530c is provided over the oxide 530b, diffusion of impurities from a structure formed above the oxide 530c to the oxide 530b can be prevented. As the oxide 530, an oxide semiconductor of one of the above metal oxides can be used.

[0263] The oxide 530c is preferably provided in the opening provided in the insulator 580 with the insulator 574 interposed therebetween. When the insulator 574 has a barrier property, diffusion of impurities from the insulator 580 to the oxide 530 can be inhibited.

[0264] One of the conductors 542 is used as the source electrode, and the other is used as the drain electrode.

[0265] Conductors 542a and 542b can be made of metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or alloys with these elements as the main components. In particular, metal nitride films such as tantalum nitride are preferred because they have barrier properties against hydrogen or oxygen and high oxidation resistance.

[0266] In addition, although FIG. 18C , FIG. 19A and FIG. 19B The diagram shows a single-layer structure, but a multi-layer structure with two or more layers can also be used. For example, a tantalum nitride film and a tungsten film are preferably stacked. Alternatively, a titanium film and an aluminum film can also be stacked. Furthermore, a two-layer structure with an aluminum film stacked on a tungsten film, a two-layer structure with a copper film stacked on a copper-magnesium-aluminum alloy film, a two-layer structure with a copper film stacked on a titanium film, and a two-layer structure with a copper film stacked on a tungsten film can also be used.

[0267] Alternatively, a three-layer structure can be used, in which an aluminum or copper film is laminated on a titanium or titanium nitride film and a titanium or titanium nitride film is formed thereon; or a three-layer structure can be used, in which an aluminum or copper film is laminated on a molybdenum or molybdenum nitride film and a molybdenum or molybdenum nitride film is formed thereon. Additionally, transparent conductive materials containing indium oxide, tin oxide, or zinc oxide can also be used.

[0268] Alternatively, a barrier layer can be provided on the conductor 542. The barrier layer is preferably made of a material that blocks oxygen or hydrogen. By employing this structure, oxidation of the conductor 542 can be suppressed during the formation of the insulator 574.

[0269] The barrier layer can be, for example, a metal oxide. In particular, insulating films that have the ability to block oxygen or hydrogen, such as aluminum oxide, hafnium oxide, and gallium oxide, are preferred. Alternatively, silicon nitride formed by CVD can also be used.

[0270] By including a barrier layer, the range of materials that can be selected for the conductor 542 can be expanded. For example, the conductor 542 can be made of materials with low oxidation resistance and high conductivity, such as tungsten or aluminum. Alternatively, a conductor that is easy to deposit or process can be used, for example.

[0271] Insulator 550 is used as a gate insulating film. Preferably, insulator 550 is disposed within an opening in insulator 580, with oxide 530c and insulator 574 in between.

[0272] When miniaturization and high integration of transistors are advanced, a problem such as a leakage current might occur due to thinning of a gate insulating film. In that case, the insulator 550 can also have a stacked structure. By making the insulator used as a gate insulating film have a stacked structure of a high-k material and a material having thermal stability, the gate potential at the time of transistor operation can be reduced while the physical thickness is kept. Further, a stacked structure having thermal stability and a high relative dielectric constant can be realized.

[0273] The conductor 560 used as a gate electrode includes a conductor 560a and a conductor 560b over the conductor 560a. The conductor 560a preferably uses a conductive material having a function of suppressing diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, copper atoms, and the like. Further, a conductive material having a function of suppressing diffusion of oxygen (at least one of oxygen atoms, oxygen molecules, and the like, for example) (not easy to transmit the above oxygen) is preferably used. In this specification, the "function of suppressing diffusion of impurities or oxygen" means a function of suppressing diffusion of any one or all of the above impurities and the above oxygen.

[0274] When the conductor 560a has a function of suppressing diffusion of oxygen, the selection of the material of the conductor 560b can be increased. That is, by including the conductor 560a, oxidation of the conductor 560b can be suppressed, and a decrease in conductivity can be prevented.

[0275] As the conductive material having a function of suppressing diffusion of oxygen, tantalum, tantalum nitride, ruthenium, or ruthenium oxide, or the like is preferably used, for example. Further, as the conductor 560a, an oxide semiconductor which can be used for the oxide 530 can be used. In that case, by forming the conductor 560b using a sputtering method, the specific resistance of the conductor 560a can be reduced to be a conductor. The conductor can be referred to as an OC (Oxide Conductor) electrode.

[0276] As the conductor 560b, a conductive material mainly including tungsten, copper, or aluminum is preferably used. Since the conductor 560 is used as a wiring, a conductor having high conductivity is preferably used. For example, a conductive material mainly including tungsten, copper, or aluminum can be used. The conductor 560b can also have a stacked structure, and for example, a stacked structure of titanium, titanium nitride, and the above conductive material can be employed.

[0277] The insulator 574 is provided between the insulator 580 and the transistor 510A. As the insulator 574, an insulating material having a function of suppressing diffusion of impurities such as water or hydrogen and oxygen is preferably used. For example, aluminum oxide, hafnium oxide, or the like is preferably used. Further, for example, a metal oxide such as magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, or tantalum oxide, silicon oxynitride, or silicon nitride can be used.

[0278] By including the insulator 574, diffusion of impurities such as water, hydrogen, or the like contained in the insulator 580 to the oxide 530b through the oxide 530c and the insulator 550 can be suppressed. Further, the excess oxygen contained in the insulator 580 can be prevented from oxidizing the conductor 560.

[0279] The insulator 580, the insulator 582, and the insulator 584 are used as interlayer films.

[0280] Like the insulator 514, the insulator 582 is preferably used as a barrier insulating film for suppressing entry of impurities such as water or hydrogen from the outside into the transistor 510A.

[0281] Further, like the insulator 516, the dielectric constant of the insulator 580 and the insulator 584 is preferably lower than that of the insulator 582. By using a material with a low dielectric constant for the interlayer film, parasitic capacitance generated between wirings can be reduced.

[0282] In addition, the transistor 510A can be electrically connected to another structure through a plug or a wiring such as the conductor 546 embedded in the insulator 580, the insulator 582, and the insulator 584.

[0283] In addition, as a material of the conductor 546, a single layer or a stack of a conductive material such as a metal material, an alloy material, a metal nitride material, or a metal oxide material can be used. For example, a high-melting-point material such as tungsten or molybdenum which has heat resistance and conductivity is preferably used. Alternatively, a low-resistance conductive material such as aluminum or copper is preferably used. By using a low-resistance conductive material, the wiring resistance can be reduced.

[0284] For example, by using a stacked structure of a conductive material such as tantalum nitride which has barrier properties against hydrogen and oxygen and tungsten which has high conductivity as the conductor 546, diffusion of impurities from the outside can be suppressed while the conductivity of the wiring is maintained.

[0285] With the above structure, a semiconductor device including a transistor including an oxide semiconductor which has a large on-state current can be provided. Alternatively, a semiconductor device including a transistor including an oxide semiconductor which has a small off-state current can be provided. Alternatively, a semiconductor device in which the variation in electric characteristics is suppressed and the reliability is improved while the electric characteristics are stable can be provided.

[0286] Structure Example 2 of Transistor

[0287] Reference FIG. 19C , FIG. 19A and FIG. 19B A structure example of the transistor 510B is described. FIG. 19A is a top view of the transistor 510B. FIG. 19C is a cross-sectional view of a portion indicated by dot-and-dash line L1-L2 in FIG. 19A .FIG. 19A is a cross-sectional view of a portion indicated by a dotted line W1-W2 in FIG. 20A FIG. 20B In a plan view of the transistor 510B, a part of a constituent element is omitted for clarity.

[0288] The transistor 510B is a modification example of the transistor 510A. Thus, for the sake of preventing repetitive explanation, mainly the difference from the transistor 510A is described.

[0289] The transistor 510B includes a region where the conductive body 542 (the conductive body 542a and the conductive body 542b) and the oxide 530c, the insulator 550, and the conductive body 560 overlap with each other. With this structure, a transistor with a high on-state current can be provided. Further, a transistor with high controllability can be provided.

[0290] The conductive body 560 used as a gate electrode includes the conductive body 560a and the conductive body 560b over the conductive body 560a. As the conductive body 560a, a conductive material having a function of suppressing diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms is preferably used. Further, a conductive material having a function of suppressing diffusion of oxygen (at least one of, for example, oxygen atoms, oxygen molecules, and the like) is preferably used.

[0291] When the conductive body 560a has a function of suppressing diffusion of oxygen, the selection of a material of the conductive body 560b can be increased. That is, by including the conductive body 560a, oxidation of the conductive body 560b can be suppressed, and thus a decrease in conductivity can be prevented.

[0292] Further, the insulator 574 is preferably provided so as to cover the top surface and the side surface of the conductive body 560, the side surface of the insulator 550, and the side surface of the oxide 530c. As the insulator 574, an insulating material having a function of suppressing diffusion of impurities such as water or hydrogen and oxygen is preferably used. For example, aluminum oxide, hafnium oxide, or the like is preferably used. Further, for example, a metal oxide such as magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, or tantalum oxide, silicon oxynitride, or silicon nitride can be used.

[0293] By providing the insulator 574, oxidation of the conductive body 560 can be suppressed. Further, by including the insulator 574, diffusion of impurities such as water or hydrogen included in the insulator 580 to the transistor 510B can be suppressed.

[0294] Further, an insulator 576 (the insulator 576a and the insulator 576b) having barrier properties can be provided between the conductive body 546 and the insulator 580. By providing the insulator 576, oxygen of the insulator 580 can be prevented from reacting with the conductive body 546 and causing oxidation of the conductive body 546.

[0295] ​Further, by providing the insulator 576 having barrier properties, the range of materials for the conductive body of the plug or wiring can be expanded. For example, by using a metal material having a property of absorbing oxygen and having high conductivity as the conductive body 546, a semiconductor device with low power consumption can be provided. Specifically, a material with low oxidation resistance and high conductivity such as tungsten or aluminum can be used. Further, for example, a conductive body which is easy to form or process can be used.

[0296] Structure Example 3 of Transistor

[0297] Structure Example 3 of Transistor FIG. 20C FIG. 20A Structure Example 3 of Transistor FIG. 20B is a top view of the transistor 510C. FIG. 20A is a cross-sectional view of the portion indicated by the dotted line L1-L2 in FIG. 20C FIG. 20A is a cross-sectional view of the portion indicated by the dotted line W1-W2 in FIG. 20A In the top view of the transistor 510C, part of the components is omitted for clarity. FIG. 20A FIG. 20B The transistor 510C is a modification example of the transistor 510A. Thus, in order to prevent repetitive explanation, mainly the difference from the transistor 510A will be described.

[0298]

[0299] FIG. 20C The transistor 510C illustrated in FIG. 20A FIG. 20B The transistor 510C illustrated in

[0300] The transistor 510C illustrated in FIG. 20C FIG. 20A FIG. 20B The transistor 510C illustrated in

[0301] ​​​​​​​Further, the conductive body 547a (the conductive body 547b) preferably overlaps with the conductive body 542a (the conductive body 542b). With this structure, at the time of etching for forming an opening of the conductive body 546a (the conductive body 546b), the conductive body 547a (the conductive body 547b) serves as an etching stopper layer and over-etching of the oxide 530b can be prevented.

[0302] Further, in the transistor 510C, FIG. 20C , FIG. 21A and FIG. 21B , the insulator 545 can be provided in contact with the insulator 544. The insulator 544 is preferably used as a barrier insulating film for inhibiting entry of impurities such as water or hydrogen or excess oxygen from the insulator 580 side into the transistor 510C. As the insulator 545, an insulator that can be used for the insulator 544 can be used. Further, as the insulator 544, for example, an insulator such as an aluminum nitride, an aluminum titanium nitride, a titanium nitride, a silicon nitride, or a silicon oxynitride can be used.

[0303] Structure Example 4 of Transistor

[0304] Structure Example 4 of Transistor FIG. 21C , FIG. 21A and FIG. 21B of the transistor 510D will be described with reference to FIGS. 17A and 17B. FIG. 21A is a top view of the transistor 510D. FIG. 21C is a cross-sectional view of a portion indicated by dot-and-dash lines L1-L2 in FIG. 21A . FIG. 21A to FIG. 21C is a cross-sectional view of a portion indicated by dot-and-dash lines W1-W2 in FIG. 22A to FIG. 22C . In the top view of FIG. 22A , part of a component is omitted for clarity.

[0305] The transistor 510D is a modification example of the above transistor. Thus, in order to prevent repetitive description, mainly the difference from the above transistor will be described.

[0306] In FIG. 22B , the insulator 550 is included over the oxide 530c, and the metal oxide 552 is included over the insulator 550. Further, the conductive body 560 is included over the metal oxide 552, and the insulator 570 is included over the conductive body 560. Further, the insulator 571 is included over the insulator 570.

[0307] The metal oxide 552 preferably has a function of inhibiting diffusion of oxygen. By providing the metal oxide 552 which inhibits diffusion of oxygen between the insulator 550 and the conductive body 560, diffusion of oxygen to the conductive body 560 is inhibited. In other words, reduction in the amount of oxygen supplied to the oxide 530 can be inhibited. Further, oxidation of the conductive body 560 due to oxygen can be inhibited.

[0308] In addition, the metal oxide 552 can be used as part of the gate electrode. For example, an oxide semiconductor that can be used for the oxide 530 can be used as the metal oxide 552. In that case, by forming the conductor 560 by a sputtering method, the resistance value of the metal oxide 552 can be reduced to be a conductive layer. This can be referred to as an OC (Oxide Conductor) electrode.

[0309] In addition, the metal oxide 552 is sometimes used as part of the gate insulating film. Thus, in the case where silicon oxide or silicon oxynitride or the like is used for the insulator 550, a metal oxide that is a high-k material having a high relative dielectric constant is preferably used as the metal oxide 552. By employing such a stacked structure, a stacked structure having heat resistance and a high relative dielectric constant can be formed. Thus, the gate potential applied at the time of transistor operation can be reduced while the physical thickness is kept. In addition, the equivalent oxide thickness (EOT) of the insulating layer used as the gate insulating film can be reduced.

[0310] Although the metal oxide 552 in the transistor 510D is shown to have a single-layer structure, a stacked structure of two or more layers can be employed. For example, a metal oxide used as part of the gate electrode and a metal oxide used as part of the gate insulating film can be stacked.

[0311] When the metal oxide 552 is used as the gate electrode, the on-state current of the transistor 510D can be increased without reducing the effect of the electric field from the conductor 560. In addition, when the metal oxide 552 is used as the gate insulating film, by keeping the distance between the conductor 560 and the oxide 530 with the physical thickness of the insulator 550 and the metal oxide 552, the leakage current between the conductor 560 and the oxide 530 can be suppressed. Thus, by providing the stacked structure of the insulator 550 and the metal oxide 552, the physical distance between the conductor 560 and the oxide 530 and the electric field strength from the conductor 560 to the oxide 530 can be easily adjusted.

[0312] Specifically, an oxide semiconductor that can be used for the oxide 530 can be used as the metal oxide 552 by being made low in resistance. Alternatively, a metal oxide containing one or a plurality of kinds of metal selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, magnesium, and the like can be used.

[0313] In particular, it is preferable to use aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), or the like as the insulating layer containing an oxide of one or both of aluminum and hafnium. In particular, hafnium aluminate has higher heat resistance than hafnium oxide film. Thus, it is less likely to be crystallized in the heat treatment in the later step, and is thus preferable. Note that the metal oxide 552 is not an essential component and can be designed as appropriate in accordance with the transistor characteristics desired.

[0314] As the insulator 570, an insulating material having a function of inhibiting the passage of impurities such as water or hydrogen and oxygen is preferably used. For example, aluminum oxide or hafnium oxide is preferably used. With this structure, the conductor 560 can be prevented from being oxidized by oxygen from above the insulator 570. In addition, the passage of impurities such as water or hydrogen from above the insulator 570 into the oxide 230 through the conductor 560 and the insulator 550 can be inhibited.

[0315] The insulator 571 is used as a hard mask. By providing the insulator 571, the conductor 560 can be processed so that the side surface of the conductor 560 is substantially perpendicular to the substrate surface, specifically, the angle formed by the side surface of the conductor 560 and the substrate surface is greater than or equal to 75 degrees and less than or equal to 100 degrees, preferably greater than or equal to 80 degrees and less than or equal to 95 degrees.

[0316] In addition, the insulator 571 can function as a barrier layer by using an insulating material having a function of inhibiting the passage of impurities such as water or hydrogen and oxygen. In that case, the insulator 570 can not be provided.

[0317] By using the insulator 571 as a hard mask, a part of the insulator 570, the conductor 560, the metal oxide 552, the insulator 550, and the oxide 530c are selectively removed, so that the side surfaces thereof can be made substantially uniform and a part of the surface of the oxide 530b is exposed.

[0318] In addition, the transistor 510D has a region 531a and a region 531b in a part of the surface of the exposed oxide 530b. One of the region 531a and the region 531b is used as a source region and the other is used as a drain region.

[0319] The region 531a and the region 531b can be formed by introducing an impurity element such as phosphorus or boron into the surface of the exposed oxide 530b by an ion implantation method, an ion doping method, a plasma immersion ion implantation method, or a plasma treatment.

[0320] Alternatively, a metal film can be formed after part of the surface of the oxide 530b is exposed, and then heat treatment can be performed to diffuse elements included in the metal film into the oxide 530b, whereby the region 531a and the region 531b are formed.

[0321] The region of the oxide 530b into which the impurity element is introduced has a lower resistivity. For this reason, the region 531a and the region 531b are also referred to as "impurity regions" or "low-resistance regions".

[0322] The region 531a and the region 531b can be formed self-aligned by using the insulator 571 and / or the conductor 560 as a mask. Thus, the region 531a and / or the region 531b do not overlap with the conductor 560, and parasitic capacitance can be reduced. Further, a bias region is not formed between the channel formation region and the source-drain region (the region 531a or the region 531b). By forming the region 531a and the region 531b self-aligned, an increase in on-state current, a decrease in threshold voltage, an increase in operating frequency, and the like can be achieved.

[0323] Further, in order to further reduce the off-state current, a bias region can be provided between the channel formation region and the source-drain region. The bias region is a region having a high resistivity and is a region into which the introduction of the impurity element is not performed. The bias region can be formed by performing the introduction of the impurity element after the formation of the insulator 575. In this case, like the insulator 571, the insulator 575 is used as a mask. Thus, a region of the oxide 530b overlapping with the insulator 575 is not introduced with the impurity element, and thus the resistivity of the region can be kept high.

[0324] The transistor 510D includes the insulator 575 on a side surface of the insulator 570, the conductor 560, the metal oxide 552, the insulator 550, and the oxide 530c. The insulator 575 is preferably an insulator having a low relative dielectric constant. For example, silicon oxide, 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, silicon oxide having a void, or resin is preferably used. In particular, when silicon oxide, silicon oxynitride, silicon nitride oxide, or silicon oxide having a void is used for the insulator 575, an excess-oxygen region can be easily formed in the insulator 575 in a later step, and is thus preferable. Further, silicon oxide and silicon oxynitride have heat resistance, and are thus preferable. Furthermore, the insulator 575 preferably has a function of diffusing oxygen.

[0325] Further, the transistor 510D includes the insulator 574 over the insulator 575 and the oxide 530. The insulator 574 is preferably formed by a sputtering method. By the sputtering method, an insulator having few impurities such as water and hydrogen can be formed. For example, aluminum oxide is preferably used as the insulator 574.

[0326] The oxide film formed by the sputtering method sometimes extracts hydrogen from the structure formed. Therefore, the insulator 574 extracts hydrogen and water from the oxide 230 and the insulator 575, and the hydrogen concentration of the oxide 230 and the insulator 575 can be reduced.

[0327] Structure Example 5 of Transistor

[0328] Reference FIG. 22A A structure example of the transistor 510E is described. FIG. 22C is a top view of the transistor 510E. FIG. 22A is a cross-sectional view of a portion indicated by a dotted line L1-L2 in FIG. 22A FIG. 22A to FIG. 22C is a cross-sectional view of a portion indicated by a dotted line W1-W2 in FIG. 22A to FIG. 22C In the top view of FIG. 8B, part of a constituent element is omitted for clarity. FIG. 22A to FIG. 22C

[0329] The transistor 510E is a modification example of the above transistor. Thus, in order to prevent repetitive explanation, mainly the difference from the above transistor is described.

[0330] In FIG. 22A to FIG. 22C , a portion of the surface of the exposed oxide 530b includes a region 531a and a region 531b without the conductor 542. One of the region 531a and the region 531b is used as a source region, and the other is used as a drain region. Further, the insulator 573 is included between the oxide 530b and the insulator 574.

[0331] FIG. 23A to FIG. 23D The region 531 (the region 531a and the region 531b) illustrated is a region in which the oxide 530b is added with an element described below. The region 531 can be formed using a dummy gate, for example.

[0332] Specifically, a dummy gate can be provided over the oxide 530b, the dummy gate is used as a mask, and the oxide 530b is added with an element which makes the oxide 530b low-resistance. That is, the element is added to a region of the oxide 530b which does not overlap with the dummy gate, whereby the region 531 is formed. As a method for adding the element, an ion implantation method in which a source gas which is ionized is mass-separated and added, an ion doping method in which a source gas which is ionized is not mass-separated and added, and a plasma immersion ion implantation method can be used, for example.

[0333] ​​In addition, boron or phosphorus are typical elements that contribute to the low resistivity of oxide 530. Other elements that can be used include hydrogen, carbon, nitrogen, fluorine, sulfur, chlorine, titanium, and noble gases. Typical examples of noble gases include helium, neon, argon, krypton, and xenon. The concentration of this element can be measured using methods such as secondary ion mass spectrometry (SIMS).

[0334] In particular, boron and phosphorus are preferred as they can be used in production lines for amorphous silicon or low-temperature polycrystalline silicon. Existing setups can be used, thereby reducing equipment investment.

[0335] Next, an insulating film serving as insulator 573 and an insulating film serving as insulator 574 can also be formed on oxide 530b and the dummy gate. By providing a stack of insulating films serving as insulator 573 and insulating films serving as insulator 574, a region overlapping region 531 with oxide 530c and insulator 550 can be provided.

[0336] Specifically, an insulating film serving as insulator 580 is formed on an insulating film serving as insulator 574. Then, a portion of the insulating film serving as insulator 580 is removed using CMP (Chemical Mechanical Polishing) to expose the dummy gate. Next, when removing the dummy gate, it is preferable to also remove a portion of the insulator 573 that is in contact with the dummy gate. As a result, insulator 574 and insulator 573 are exposed on the side of the opening provided in insulator 580, and a portion of region 531 provided in oxide 530b is exposed on the bottom surface of the opening. Next, an oxide film serving as oxide 530c, an insulating film serving as insulator 550, and a conductive film serving as conductor 560 are sequentially formed at the opening. Then, a portion of the oxide film serving as oxide 530c, the insulating film serving as insulator 550, and the conductive film serving as conductor 560 are removed using CMP or similar methods until insulator 580 is exposed, thereby forming... FIG. 23A The transistor shown.

[0337] Note that insulators 573 and 574 are not necessarily required. They can be designed appropriately based on the desired transistor characteristics.

[0338] FIG. 23B The transistor shown can utilize existing devices and does not require conductor 542, thereby reducing costs.

[0339] Furthermore, this embodiment can be implemented in combination with other embodiments described in this specification.

[0340] (Implementation Method 4)

[0341] In this embodiment, one example of an electronic device that can use the semiconductor device described in the above embodiment is described.

[0342] The semiconductor device according to one embodiment of the present application can be mounted on various electronic devices. In particular, the semiconductor device according to one embodiment of the present application can be used as an IC for a control processor in an electronic device that is expected to be used in a high-temperature environment. As examples of electronic devices, there are, for example, a moving object such as a vehicle, a vacuum cleaner, a microwave oven, an electric oven, an electric rice cooker, a water heater, an IH cooker, a water dispenser, a cooling and heating air conditioner including an air conditioner, a washing machine, a clothes dryer, an audio-visual device, and the like.

[0343] FIG. 23C An example of an electronic device is shown.

[0344] FIG. 23D FIG. 57 is a diagram showing a car 5700 as one example of a moving object. The semiconductor device described in the above embodiment can be used for a control system that controls devices such as sensors and actuators in the car 5700.

[0345] ​ FIG. 58 is a diagram showing an electric motorcycle 5800 as one example of a moving object. The semiconductor device described in the above embodiment can be used for a control system that controls devices such as sensors and actuators in the electric motorcycle 5800 or can be used for a battery management system.

[0346] Note that although a car and an electric motorcycle are described as examples of a moving object in the above description, a moving object is not limited to a car or an electric motorcycle. For example, a moving object can be a train, a monorail, a ship, a flying object (a helicopter, an unmanned aerial vehicle (drone), an airplane, a rocket), or the like, and the semiconductor device according to one embodiment of the present application can be used for such a moving object.

[0347] ​ FIG. 59 shows a microwave oven 5900 as one example of an electronic device. The semiconductor device described in the above embodiment can be used for an IC for control of a power device that causes current to flow in the microwave oven 5900, or the like.

[0348] ​ FIG. 60 shows an electric refrigerator-freezer 6000 as one example of an electronic device. The semiconductor device described in the above embodiment can be used for an IC for control of a power device that causes current to flow in the electric refrigerator-freezer 6000, or the like.

[0349] The semiconductor device according to one embodiment of the present application can perform highly reliable operation in a high-temperature environment and can achieve low power consumption. In addition, low power consumption of an electronic device can be achieved.

[0350] In addition, the present embodiment can be implemented in combination with other embodiments described in the present specification as appropriate.

[0351] (Additional Explanation of Descriptions in the Present Specification, etc.)

[0352] Hereinafter, additional explanation will be given of the descriptions of the above-described embodiments and each structure in the embodiments.

[0353] The structure shown in each embodiment can be combined with the structure shown in another embodiment to constitute one mode of the present application. In addition, when a plurality of structure examples are shown in one embodiment, these structure examples can be combined as appropriate.

[0354] In addition, the content (or a part thereof) described in an embodiment can be applied to, combined with, or replaced with the content (or a part thereof) described in another content in the same embodiment and / or the content (or a part thereof) described in one or more other embodiments.

[0355] In addition, the content described in the embodiments refers to the content described with reference to each drawing in each embodiment or the content described using the literal description in the specification.

[0356] In addition, a greater number of drawings can be constituted by combining the drawing (or a part thereof) shown in an embodiment with other parts of the drawing, other drawings shown in the same embodiment, and / or drawings (or a part thereof) shown in one or more other embodiments.

[0357] Furthermore, in the present specification, etc., constituent elements are classified in accordance with functions and represented in blocks in each block independently of each other. However, there are cases where it is difficult to distinguish constituent elements in accordance with functions in actual circuits, etc., one circuit involves a plurality of functions, or a plurality of circuits involve one function. Therefore, the blocks in the block diagrams are not limited to the constituent elements described in the specification, and can be expressed in another manner as appropriate according to the situation.

[0358] Further, in the drawings, any dimensional, layer thickness, or region is arbitrarily shown for convenience of explanation. Therefore, the present application is not limited to the dimensions in the drawings. Further, the drawings are schematically shown for the sake of clarity, and are not limited to the shapes or values shown in the drawings. For example, a signal, voltage, or current unevenness caused by noise, or a signal, voltage, or current unevenness caused by a time deviation can be included.

[0359] In this specification and the like, when a connection relation of a transistor is described using the phrase "one of a source and a drain" (or a first electrode or a first terminal) or "the other of a source and a drain" (or a second electrode or a second terminal), this means that the source and the drain of the transistor are interchangeable. That is, the source and the drain of the transistor are interchangeable. Further, the source and the drain of the transistor are also referred to as a source (drain) terminal or a source (drain) electrode, for example.

[0360] Further, in this specification and the like, the term "electrode" or "wiring" does not limit the function of the element. For example, an "electrode" is sometimes used as part of a "wiring", and vice versa. Furthermore, the term "electrode" or "wiring" also includes a combination of a plurality of "electrodes" and a plurality of "wirings", for example.

[0361] In addition, in this specification and the like, a voltage and a potential can be appropriately changed with each other. The voltage refers to a potential difference from a potential serving as a reference, and for example, when the potential serving as the reference is a ground potential, the voltage can be changed to the potential. The ground potential does not always mean 0 V. Furthermore, the potential is relative, and a potential supplied to a wiring or the like is sometimes changed depending on the potential serving as the reference.

[0362] Further, in this specification and the like, the term "film" and the term "layer" and the like are changed with each other as appropriate depending on the situation or the context. For example, the term "conductive layer" is changed to the term "conductive film" in some cases. Further, for example, the term "insulating film" is changed to the term "insulating layer" in some cases.

[0363] In this specification and the like, a switch means an element having a function of controlling whether current flows or not by being changed to an on state (open state) or an off state (closed state). Alternatively, a switch means an element having a function of selecting and switching a path of current.

[0364] In this specification and the like, for example, a channel length means a distance between a source and a drain in a region where a semiconductor (or a portion in the semiconductor where current flows when the transistor is in an on state) and a gate overlap with each other or a region where a channel is formed, in a plan view of the transistor.

[0365] In this specification and the like, the channel width is the length of a portion in the direction in which a channel is formed, or the length of a portion in the direction in which a source electrode and a drain electrode of a transistor face each other, in a region in which a semiconductor (or a portion of a semiconductor in which current flows when the transistor is in an on state) and a gate electrode overlap with each other. Note that the channel width is measured at a portion where the channel width is not changed with time by etching or the like.

[0366] In this specification and the like, the term "connected" includes the case where directly connected and the case where not directly connected through an object. Here, the case where "A and B are electrically connected" means that an object having some function is interposed between A and B, and enables transmission or reception of an electrical signal between A and B.

[0367] [Explanation of symbols]

[0368] IN1: terminal, IN2B: terminal, L1-L2: dotted line, T1: time, T2: time, T3: time, T4: time, T5: time, T6: time, T7: time, T8: time, T11: time, T12: time, T13: time, T14: time, T21: time, T22: time, T23: time, T24: time, T25: time, T26: time, T27: time, 100: semiconductor device, 100A: semiconductor device, 101: signal generating circuit, 102: logic circuit, 102B: logic circuit, 102C: logic circuit, 102D: logic circuit, 102E: logic circuit, 111: transistor, 112: transistor, 113: transistor, 114: transistor, 115: transistor, 121: transistor, 122: transistor, 123: transistor, 124: transistor, 125: transistor, 126: transistor, 127: transistor, 128: transistor, 131: transistor, 138: transistor, 151: transistor, 165: transistor, 201: signal processing circuit, 202: logic circuit, 202A: logic circuit, 202B: logic circuit, 202C: logic circuit, 202D: logic circuit, 203: switching circuit, 203A: switching circuit, 203B: switching circuit, 203C: switching circuit, 203D: switching circuit, 230: oxide, 300: transistor, 500: transistor, 510A: transistor, 510B: transistor, 510C: transistor, 510D: transistor, 510E: transistor, 511: insulator, 512: insulator, 514: insulator, 516: insulator, 520: insulator, 521: insulator, 522: insulator, 524: insulator, 530: oxide, 530a: oxide, 530b: oxide, 530c: oxide, 531: region, 531a: region, 531b: region, 540a: conductive body, 540b: conductive body, 542: conductive body, 542a: conductive body, 542b: conductive body, 543: region, 543a: region, 543b: region, 544: insulator, 545: insulator, 546: conductive body, 546a: conductive body, 546b: conductive body, 547: conductive body, 547a: conductive body, 547b: conductive body, 550: insulator, 552: metal oxide, 560: conductive body, 560a: conductive body, 560b: conductive body, 570: insulator, 571: insulator, 573: insulator, 574: insulator, 575: insulator, 576: insulator, 576a: insulator, 576b: insulator, 580: insulator, 581: insulator, 582: insulator, 584: insulator, 5700: automobile, 5800: electric motorcycle, 5900: microwave oven, 6000: electric refrigerator-freezer, 7000A: IC,7000B: IC, 7001: lead, 7002: printed circuit board, 7003A: circuit portion, 7003B: circuit portion, 7004: circuit board, 7031: OS transistor layer, 7032: wiring layer, 7033: OS transistor layer.

Claims

1. A semiconductor device comprising: a first input terminal and a second input terminal; a first output terminal and a second output terminal; a first wiring and a second wiring; and a first transistor, a second transistor, a third transistor, and a fourth transistor, wherein one of a source and a drain of the first transistor is electrically connected to the first wiring, one of a gate and a back gate of the first transistor is electrically connected to the first input terminal, the other of the source and the drain of the first transistor and the other of the gate and the back gate of the first transistor are electrically connected to the second output terminal, one of a source and a drain of the second transistor is electrically connected to the first wiring, one of a gate and a back gate of the second transistor is electrically connected to the second input terminal, the other of the source and the drain of the second transistor and the other of the gate and the back gate of the second transistor are electrically connected to the first output terminal, a gate and a back gate of the third transistor are electrically connected to the first input terminal, one of a source and a drain of the third transistor is electrically connected to the first output terminal, the other of the source and the drain of the third transistor is electrically connected to the second wiring, and a gate and a back gate of the fourth transistor are electrically connected to the second input terminal, one of a source and a drain of the fourth transistor is electrically connected to the second output terminal, the other of the source and the drain of the fourth transistor is electrically connected to the second wiring.

2. The semiconductor device according to claim 1, wherein the first to fourth transistors each contain a metal oxide in a channel formation region.

3. A semiconductor device comprising: a first input terminal and a second input terminal; a first output terminal and a second output terminal; a first wiring, a second wiring, and a third wiring; and a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, and an eighth transistor, wherein one of a source and a drain of the first transistor is electrically connected to the first wiring, one of a gate and a back gate of the first transistor is electrically connected to the first input terminal, the other of the source and the drain of the first transistor and the other of the gate and the back gate of the first transistor are electrically connected to a gate and a back gate of the second transistor, one of a source and a drain of the second transistor is electrically connected to the second wiring, the other of the source and the drain of the second transistor is electrically connected to the second output terminal, one of a source and a drain of the third transistor is electrically connected to the first wiring, one of a gate and a back gate of the third transistor is electrically connected to the second input terminal, the other of the source and the drain of the third transistor and the other of the gate and the back gate of the third transistor are electrically connected to a gate and a back gate of the fourth transistor, one of a source and a drain of the fourth transistor is electrically connected to the second wiring, the other of the source and the drain of the fourth transistor is electrically connected to the first output terminal, ​ ​ one of a source and a drain of the fifth transistor is electrically connected to the fourth transistor, and the other of the source and the drain of the fifth transistor is electrically connected to the third wiring, one of a source and a drain of the sixth transistor is electrically connected to the first output terminal, and the other of the source and the drain of the sixth transistor is electrically connected to the third wiring, one of a source and a drain of the seventh transistor is electrically connected to the second transistor, and the other of the source and the drain of the seventh transistor is electrically connected to the third wiring, and one of a source and a drain of the eighth transistor is electrically connected to the second output terminal, and the other of the source and the drain of the eighth transistor is electrically connected to the third wiring.

4. The semiconductor device according to claim 3, wherein a first potential supplied to the first wiring is higher than a second potential supplied to the second wiring.

5. The semiconductor device according to claim 3, wherein each of the first to eighth transistors contains a metal oxide in a channel formation region.

6. The semiconductor device according to claim 2 or 5, wherein the metal oxide contains at least In (indium) or Zn (zinc).

7. The semiconductor device according to claim 6, wherein the metal oxide contains Ga (gallium).

8. A semiconductor device comprising: a plurality of switching circuits; and a plurality of logic circuits, wherein each logic circuit includes: a first input terminal and a second input terminal; a first output terminal and a second output terminal; a first wiring, a second wiring, and a third wiring; and a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, and an eighth transistor, one of a source and a drain of the first transistor is electrically connected to the first wiring, one of a gate and a back gate of the first transistor is electrically connected to the first input terminal, the other of the source and the drain of the first transistor and the other of the gate and the back gate of the first transistor are electrically connected to a gate and a back gate of the second transistor, one of a source and a drain of the second transistor is electrically connected to the second wiring, the other of the source and the drain of the second transistor is electrically connected to the second output terminal, one of a source and a drain of the third transistor is electrically connected to the first wiring, one of a gate and a back gate of the third transistor is electrically connected to the second input terminal, the other of the source and the drain of the third transistor and the other of the gate and the back gate of the third transistor are electrically connected to a gate and a back gate of the fourth transistor, one of a source and a drain of the fourth transistor is electrically connected to the first wiring, one of a gate and a back gate of the fourth transistor is electrically connected to the second input terminal, the other of the source and the drain of the fourth transistor and the other of the gate and the back gate of the fourth transistor are electrically connected to a gate and a back gate of the fifth transistor, One of a source and a drain of the fourth transistor is electrically connected to the second wiring, and the other of the source and the drain of the fourth transistor is electrically connected to the first output terminal, the gate and the back gate of the fifth transistor are electrically connected to the first input terminal, one of a source and a drain of the fifth transistor is electrically connected to the gate and the back gate of the fourth transistor, and the other of the source and the drain of the fifth transistor is electrically connected to the third wiring, the gate and the back gate of the sixth transistor are electrically connected to the first input terminal, one of a source and a drain of the sixth transistor is electrically connected to the first output terminal, and the other of the source and the drain of the sixth transistor is electrically connected to the third wiring, the gate and the back gate of the seventh transistor are electrically connected to the second input terminal, one of a source and a drain of the seventh transistor is electrically connected to the gate and the back gate of the second transistor, and the other of the source and the drain of the seventh transistor is electrically connected to the third wiring, and the gate and the back gate of the eighth transistor are electrically connected to the second input terminal, one of a source and a drain of the eighth transistor is electrically connected to the second output terminal, and the other of the source and the drain of the eighth transistor is electrically connected to the third wiring.

9. The semiconductor device according to claim 8, wherein a first potential supplied to the first wiring is higher than a second potential supplied to the second wiring.

10. The semiconductor device according to claim 8 or 9, wherein each of the first to eighth transistors contains a metal oxide in a channel formation region.

11. The semiconductor device according to claim 8 or 9, wherein the switching circuit includes a transistor, and the transistor contains a metal oxide in a channel formation region.

12. The semiconductor device according to claim 8 or 9, wherein any of the plurality of switching circuits has a function of holding a potential corresponding to data held in the logic circuit when becoming a non-conductive state.

13. The semiconductor device according to claim 10, wherein the metal oxide contains at least In (indium) or Zn (zinc).

14. The semiconductor device according to claim 10, wherein the metal oxide contains Ga (gallium).

15. The semiconductor device according to claim 8 or 9, wherein at least one of the first to eighth transistors contains a metal oxide in a channel formation region, and the metal oxide contains In (indium) and Zn (zinc).

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