Semiconductor equipment

Abstract

To provide a semiconductor device that is highly productive, consumes little power, is reliable, and includes a unipolar logic circuit. [Solution] A semiconductor device 100 that prevents a decrease in the output voltage of a logic circuit by boosting the gate voltage using a capacitive element 117, wherein the drain and gate of transistor 111 are connected to wiring 121 and the source is connected to node 131; the drain of transistor 112 is connected to node 131, the source is connected to wiring 122 and the gate is connected to node 132; the drain of transistor 113 is connected to wiring 123, the source is connected to node 133 and the gate is connected to node 131; the drain of transistor 114 is connected to node 133, the source is connected to wiring 124 and the gate is connected to node 132; one electrode of the capacitive element is connected to node 131 and the other electrode is connected to node 133. It is preferable to use an OS transistor for the transistor.

Description

[Technical Field]

[0001] One aspect of the invention disclosed herein relates to a product, a method, or a method of manufacture. Alternatively, one aspect of the invention disclosed herein is a process, machine, manufacture or relating to compositions of matter. In particular, this specification One aspect of the invention disclosed in this book, etc. relates to a semiconductor device and an electronic device having a semiconductor device. It is.

[0002] In this specification, a semiconductor device refers to a device that can function by utilizing semiconductor properties. This refers to a general category, including display devices (liquid crystal displays, light-emitting displays, etc.), lighting devices, and electro-optical devices. Energy storage devices, memory devices, semiconductor circuits, imaging devices, and electronic devices, etc., have semiconductor devices. There are cases where this is the case. [Background technology]

[0003] In recent years, oxide semiconductors (OS) have been used in semiconductor layers where channels are formed. Transistors using an inductor (hereinafter also referred to as "OS transistors") It is being considered. Oxide semiconductors can be deposited using methods such as sputtering, for example, It can be used in the semiconductor layer of transistors that make up large display devices. A transistor is a transistor that uses amorphous silicon in the semiconductor layer where the channel is formed. Since it is possible to modify and utilize some of the production equipment, it has the advantage of reducing capital investment. There's also a to.

[0004] Furthermore, OS transistors are known to have extremely low leakage current in the non-conductive state. For example, a low-power CPU that applies the characteristic of extremely low leakage current of an OS transistor is disclosed (see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, it is known that it is difficult to realize a p-channel type transistor with an OS transistor. Therefore, in order to configure a logic circuit using only OS transistors, it is necessary to configure a unipolar logic circuit.

[0007] [[ID=�2]] On the other hand, even if a p-channel type transistor can be realized, if p-channel type transistors and n-channel type transistors are separately fabricated on the same substrate, the number of manufacturing steps increases, resulting in an increase in the manufacturing cost of the semiconductor device and a decrease in productivity. Therefore, it is preferable that the thin film transistors fabricated on the same substrate are transistors of the same conductivity type. However, in a unipolar logic circuit composed of transistors of the same conductivity type, there is a problem that the output voltage decreases by the amount corresponding to the threshold voltage of the transistor.

[0008] One aspect of the present invention is to provide a semiconductor device with good productivity. Another aspect is to provide a semiconductor device with low power consumption. Or, one aspect is to provide a semiconductor device with good reliability. Or, one aspect of the present invention is ​​​​​​​​​​One of the objectives is to provide semiconductor devices, etc., that include unipolar logic circuits. Alternatively, novel One of our objectives is to provide semiconductor devices and the like.

[0009] Furthermore, the description of these problems does not preclude the existence of other problems. The approach does not need to solve all of these problems. This will become clear from the description in the specification, drawings, claims, etc., and the specification, drawings It is possible to extract other issues from the descriptions in the surfaces, claims, etc. [Means for solving the problem]

[0010] One aspect of the present invention comprises a first to fourth transistor and a capacitive element, One of the sources or drains of the transistor is electrically connected to the first wiring, and the first transistor The gate of the transistor is electrically connected to the first wiring, and the source or drain of the first transistor The other end of the input is electrically connected to either the source or drain of the second transistor, The source or drain of the two transistors is electrically connected to the second wiring, and the second transistor The gate of the transistor is electrically connected to the gate of the fourth transistor, and the gate of the third transistor Either the source or the drain is electrically connected to the third wire, and the source of the third transistor Alternatively, the other end of the drain is electrically connected to either the source or the drain of the fourth transistor. The gate of the third transistor is connected to the source or drain of the first transistor. Electrically connected, the source or drain of the fourth transistor is electrically connected to the fourth wiring. It is connected, and one electrode of the capacitive element is electrically connected to the gate of the third transistor. The other electrode of the element is electrically connected to the other source or drain of the third transistor. This semiconductor device is characterized by the following features.

[0011] Alternatively, one aspect of the present invention comprises a first to fourth transistor and a capacitive element, Each of the first to fourth transistors has a first gate and a second gate. The first transistor has a gate, and the first gate of the first transistor is electrically connected to the first wiring, and the first transistor The second gate of the transistor is electrically connected to the first wiring, and the source or drain of the first transistor. One end of the input is electrically connected to the first wiring, and the source or drain of the first transistor The other end is electrically connected to either the source or drain of the second transistor, The source or drain of the transistor is electrically connected to the second wiring, and the other is connected to the second transistor. The first gate of the second transistor is electrically connected to the second gate of the third transistor. Either the source or drain is electrically connected to the third wiring, and the first gate of the third transistor. The terminal is electrically connected to the source or drain of the first transistor, and the third transistor The second gate of the transistor is electrically connected to the other side of the source or drain of the third transistor. And either the source or drain of the fourth transistor is connected to the source or of the third transistor. The other end of the drain is electrically connected, and the source or the other end of the drain of the fourth transistor is The fourth wire is electrically connected, and the first gate of the fourth transistor is connected to the second gate of the fourth transistor. The gate is electrically connected, and the first gate of the second transistor is connected to the first gate of the fourth transistor. The electrode of the capacitive element is electrically connected to the gate of the third transistor, and one electrode of the capacitive element is electrically connected to the first gate of the third transistor. They are connected in a specific way, and the other electrode of the capacitive element is the other of the source or drain of the third transistor. This semiconductor device is characterized by being electrically connected to the first gate and the second gate. One end of the gate functions as a gate, and the other end functions as a back gate.

[0012] The above transistor preferably contains an oxide semiconductor in the semiconductor layer where the channel is formed. stomach.

[0013] It is preferable that the channel length of the second transistor is shorter than the channel length of the first transistor. Also, the channel width of the second transistor is longer than the channel width of the first transistor. It is preferable. [Effects of the Invention]

[0014] We can provide semiconductor devices with high productivity, or semiconductors with low power consumption. We can provide devices, etc. Or, we can provide reliable semiconductor devices, etc. This is possible. Alternatively, a semiconductor device including a unipolar logic circuit can be provided. Alternatively, we can provide novel semiconductor devices and the like.

[0015] Furthermore, the description of these effects does not preclude the existence of other effects. The embodiment does not need to have all of these effects. Other effects are described in the specification. This will become clear from the descriptions in the drawings and claims, and the specification, drawings, and claims will be clear from the description, drawings, and claims. It is possible to extract other effects from any of these descriptions. [Brief explanation of the drawing]

[0016] [Figure 1] A circuit diagram illustrating a semiconductor device. [Figure 2] A timing chart illustrating the operation of a semiconductor device. [Figure 3] A circuit diagram illustrating the operation of a semiconductor device. [Figure 4] A circuit diagram illustrating the operation of a semiconductor device. [Figure 5] A circuit diagram illustrating a semiconductor device. [Figure 6] A timing chart illustrating the operation of a semiconductor device. [Figure 7] A circuit diagram illustrating the operation of a semiconductor device. [Figure 8] A circuit diagram illustrating the operation of a semiconductor device. [Figure 9] A circuit diagram illustrating a semiconductor device. [Figure 10] A diagram illustrating an example of a transistor. [Figure 11] A diagram illustrating an example of a transistor. [Figure 12] A diagram illustrating an example of a transistor. [Figure 13] A diagram illustrating an example of a transistor. [Figure 14] A diagram illustrating an example of a transistor. [Figure 15] A diagram illustrating an example of a transistor. [Figure 16] A diagram illustrating an example of a transistor. [Figure 17] A diagram illustrating an example of a transistor. [Figure 18] A diagram illustrating an example of a transistor. [Figure 19] A diagram illustrating an example of a transistor. [Figure 20] A diagram illustrating the energy band structure. [Figure 21] A flowchart and perspective diagram illustrating an example of the manufacturing process for electronic components. [Figure 22] A diagram illustrating an example of an electronic device. [Figure 23] A diagram illustrating an example of an electronic device. [Modes for carrying out the invention]

[0017] Embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description. Without departing from the spirit and scope of the present invention, its form and details may be modified in various ways. It will be easily understood by those skilled in the art to obtain this. Therefore, the present invention is as shown in the embodiments below. The description is not to be interpreted as being limited to the stated content. The same reference numeral is used in common across different drawings for parts that are identical or have similar functions. The explanation of that repetition may be omitted in some cases.

[0018] Furthermore, the position, size, and scope of each component shown in the drawings, etc., are intended to facilitate understanding of the invention. Therefore, the actual location, size, and range may not be represented. The invention is not necessarily limited to the position, size, scope, etc. disclosed in drawings or other documents.

[0019] Furthermore, in order to facilitate understanding of the invention, the description of some components may be omitted in the drawings. There are some discrepancies. Also, some hidden lines and other details may be omitted.

[0020] In this specification, ordinal numbers such as "the first," "the second," etc., are used to avoid confusion of constituent elements. This is merely a label and does not indicate any order or ranking, such as process sequence or layering sequence. Furthermore, even for terms that do not have ordinal numbers attached in this specification, etc., confusion of constituent elements should be avoided. Therefore, ordinal numbers may be used in the claims. Also, in this specification, etc. Even if a term has an ordinal number attached to it, if a different ordinal number is attached in the claims, In some cases, this may be the case. Also, even if a term is given an ordinal number in this specification, etc., patent Ordinal numbers may be omitted in the scope of claims, etc.

[0021] Furthermore, in this specification, the terms "electrode" and "wiring" do not limit the functionality of these components. It is not fixed. For example, "electrode" can be used as part of "wiring". The reverse is also true. Furthermore, the terms "electrode" and "wiring" can refer to multiple "electrodes" and "wiring". This also includes cases where the "lines" are formed as a single unit.

[0022] In this specification, the terms "above" and "below" refer to the relative positions of the constituent elements, specifically whether they are directly above or below. It is not limited to being below and in direct contact. For example, "electrode on insulating layer A" If the expression is "B", then it is not necessary for electrode B to be formed in direct contact with insulating layer A. Cases containing other components between marginal layer A and electrode B are not excluded.

[0023] Furthermore, the source and drain functions may differ when using transistors with different polarities, or when rotating In circuit operation, the direction of the current changes, and depending on the operating conditions, they can be swapped. Therefore, it is difficult to determine which is the source and which is the drain. In this specification, the terms source and drain may be used interchangeably. Let's assume that.

[0024] Furthermore, if it is explicitly stated in this specification, etc., that X and Y are connected. This refers to the case where X and Y are electrically connected, and the case where X and Y are functionally connected. The cases in which X and Y are directly connected are disclosed in this specification, etc. Therefore, the connection relationships are not limited to predetermined relationships, such as those shown in the diagram or text. Connections other than those shown in the diagram or text are also included as those described in the diagram or text. ru.

[0025] Furthermore, in this specification, "electrically connected" means "having some kind of electrical effect." This includes cases where the connection is made via ". Here, "something that has some electrical effect" The term "connection" is not particularly limited as long as it enables the exchange of electrical signals between connected objects. Therefore, even when expressed as "electrically connected," in actual circuits, In some cases, there is no logical connection point, and the wiring simply extends without any apparent purpose.

[0026] Note that channel length refers to, for example, the length of the semiconductor (or transistor) in a top view of a transistor. When the zista is in the ON state, the part of the semiconductor through which current flows and the gate electrode overlap each other. In the region where channels are formed, or the region where channels are formed (also called the "channel-forming region") , source (source region or source electrode) and drain (drain region or drain electrode) This refers to the distance between ). Note that in a single transistor, if the channel length is in all regions They don't necessarily take the same value. That is, the channel length of a transistor is not fixed to a single value. This may not always be the case. Therefore, in this specification, the channel length is defined as the region in which the channel is formed. This is one of the values, the maximum value, the minimum value, or the mean value in the given range.

[0027] Channel width refers to, for example, the channel width of a semiconductor (or transistor) when it is in the ON state. The region where the current-carrying part and the gate electrode overlap, or the region where a channel is formed. This refers to the length of the portion in the region where the source and drain face each other. In a transistor, the channel width is not necessarily the same across all regions. That is, The channel width of a transistor may not be fixed to a single value. Therefore, this specification In the book, the channel width is any one value, the maximum value, in the region where the channel is formed. Use the minimum or average value.

[0028] Furthermore, depending on the transistor structure, the channel may actually be formed in the region where the channel is formed. Channel width (also called "effective channel width") and shown in the top view of the transistor. The channel width (also called the "apparent channel width") may differ from the actual channel width. For example, When the gate electrode covers the side of the semiconductor layer, the effective channel width is less than the apparent channel width. It can become larger than that, and its effects may become undeniable. For example, when dealing with minute and gate electricity In transistors where the electrodes cover the side surface of the semiconductor, the channel region formed on the side surface of the semiconductor is divided. The combined size may become larger. In that case, the effective channel width is greater than the apparent channel width. The width will increase.

[0029] In such cases, it can be difficult to estimate the effective channel width through actual measurements. For example, in order to estimate the effective channel width from the design value, the shape of the semiconductor is known. An assumption is necessary. Therefore, if the shape of the semiconductor is not precisely known, the effective method is It is difficult to accurately measure channel width.

[0030] Therefore, in this specification, the apparent channel width is referred to as the "enclosed channel width (SCW:Su It is sometimes referred to as "rounded channel width." Also, in this specification... So, when simply referring to channel width, it means the enclosed channel width or apparent channel width It may refer to the channel width. Or, in this specification, when it is simply referred to as channel width, it refers to the actual It may refer to the effective channel width. Note that channel length, channel width, and effective channel Width, apparent channel width, enclosed channel width, etc., can be determined by analyzing cross-sectional TEM images, etc. The value can be determined by factors such as [specific factors].

[0031] Furthermore, the field-effect mobility of the transistor and the current value per channel width are calculated to determine this. In some cases, the calculation may be performed using the enclosed channel width. In that case, the effective channel The values ​​may differ from those obtained when calculating using the channel width.

[0032] Furthermore, the transistors described herein, unless otherwise explicitly stated, are enhancement transistors. This is a normally-off type field-effect transistor.

[0033] Furthermore, semiconductor impurities refer to components other than the main components that make up the semiconductor, for example, concentration. Elements present in less than 0.1 atomic percent are considered impurities. The presence of impurities can, for example, lead to... The conductor's DOS (Density of States) increases, and carrier movement In some cases, the degree of quality may decrease, or the crystallinity may decrease. In the case of conductors, impurities that alter the properties of semiconductors include, for example, Group 1 elements and Group 2 elements. Other than the main components of Group 13, Group 14, Group 15 elements, and oxide semiconductors. These include transition metals, and in particular, for example, hydrogen (also found in water), lithium, and sodium. These include silicon, boron, phosphorus, carbon, nitrogen, etc. In the case of oxide semiconductors, for example, hydrogen The presence of various impurities can lead to the formation of oxygen vacancies. Also, if the semiconductor is silicon... In this case, impurities that alter the properties of semiconductors include, for example, Group 1 elements other than oxygen and hydrogen. These include elements from Group 2, Group 13, Group 15, and so on.

[0034] Furthermore, in this specification, "parallel" means that two straight lines are at an angle of -10° or more and 10° or less. This refers to the state in which something is positioned. Therefore, it also includes cases where the angle is between -5° and 5°. Also, "abbreviated "Parallel" refers to a state where two straight lines are positioned at an angle between -30° and 30°. Furthermore, "perpendicular" and "orthogonal" refer to two lines positioned at an angle of 80° to 100°. This refers to a state in which something is tilted. Therefore, it also includes cases where the angle is between 85° and 95°. "Straight" refers to a state in which two straight lines are positioned at an angle between 60° and 120°.

[0035] In this specification, etc., the terms "identical," "same," and "equal" are used to refer to count values ​​and measured values. When saying "uniform" or "uniform" (including synonyms for these), unless otherwise specified. The result should include an error margin of plus or minus 20%.

[0036] Furthermore, in this specification, when an etching process is performed after a photolithography process, Unless otherwise specified, the resist mask formed in the photolithography process is It shall be removed after the finishing process is complete.

[0037] Furthermore, in this specification, etc., the high power supply potential VDD (hereinafter simply referred to as "VDD" or "H potential") Also called (or (VSS)). This refers to a power supply potential that is higher than the low power supply potential VSS. The VSS (hereinafter also simply referred to as "VSS" or "L potential") is the high power supply potential VDD. It shows a power supply potential that is lower than [the specified potential]. Also, the ground potential can be used as VDD or VSS. It is also possible that, for example, if VDD is at ground potential, then VSS is at a potential lower than ground potential. If VSS is at ground potential, then VDD is at a higher potential than ground potential.

[0038] Furthermore, generally speaking, "voltage" refers to a potential relative to a reference potential (for example, ground potential (GND potential)). It often refers to the potential difference with respect to the source potential, etc. Also, "potential" is relative. Therefore, the potential supplied to wiring, etc., may change depending on the reference potential. "Voltage" and "potential" can sometimes be used interchangeably. Note that in this specification, Unless otherwise specified, VSS shall be the reference potential.

[0039] Note that the words "membrane" and "layer" may differ in some cases or depending on the situation. Therefore, they can be interchanged. For example, the term "conductive layer" can be replaced with "conductive film." In some cases, it may be possible to change the term to "insulating film". Alternatively, for example, the term "insulating film" may be used. In some cases, it may be possible to change the term to "insulating layer."

[0040] Furthermore, in this specification, if a crystal is trigonal or rhombohedral, it will be represented as a hexagonal crystal system. .

[0041] (Embodiment 1) A semiconductor device 100 according to one aspect of the present invention will be described with reference to the drawings. Figure 1(A) shows a semiconductor This is a circuit diagram illustrating the configuration of the main unit 100.

[0042] <<Example configuration of semiconductor device 100>> The semiconductor device 100 shown in Figure 1(A) includes transistors 111 to 114, It has a capacitor element 117. Transistors 111 to 114 are source, It is an n-channel transistor having a drain, gate, and back gate.

[0043] The gate and back gate are positioned so as to sandwich the channel formation region of the semiconductor layer between them. Therefore, the back gate can be made to function like a gate. The potential may be the same as the gate potential, or it may be the ground potential (GND potential), or any other potential. This is also good. Furthermore, by changing the potential of the back gate independently of the gate, The threshold voltage of the transistor can be changed. In this specification, the gate or buck voltage can be varied. Sometimes one of the gates is called "Gate 1" and the other is called "Gate 2". ru.

[0044] In the semiconductor device 100 shown in Figure 1(A), the first gate and The second gate is electrically connected to wiring 121, with either the source or drain being connected to wiring 121. The other end of the source or drain is electrically connected to node 131. Also, one of the sources or drains of transistor 112 is electrically connected to node 131. They are connected, and the other of the source or drain is electrically connected to the wiring 122, and the first gate The first and second gates are electrically connected to node 132. Also, transistor 11 3, either the source or the drain is electrically connected to the wiring 123, and the source or drain The other end of the gate is electrically connected to node 133, and either the first gate or the second gate is connected to the node 133. It is electrically connected to node 133, and the other of the first gate or the second gate is electrically connected to node 131. They are electrically connected. Also, one of the sources or drains of transistor 114 is connected to the Electrically connected to wire 133, the other being either source or drain, is electrically connected to wire 124. The first and second gates are electrically connected to node 132. One electrode of the capacitive element 117 is electrically connected to node 131, and the other electrode is connected to node 131. It is electrically connected to 133. Also, node 132 is electrically connected to terminal 102. Node 133 is electrically connected to terminal 105.

[0045] By adding a back gate in addition to the gate, the carrier when the transistor is ON... Because the flow region becomes larger in the film thickness direction, the amount of carrier movement increases. As a result, the on-current of the transistor increases, and the field-effect mobility also increases. So, a transistor with a back gate has a transistor that can handle the required on-current. The occupied area can be reduced. Also, the semiconductor layer is covered with a gate and a back gate. This reduces the influence of external electric fields on the channel formation region, thereby improving the reliability of semiconductor devices. This can improve performance. Further details regarding the back gate will be explained later.

[0046] Furthermore, if the same potential is supplied to both wiring 121 and wiring 123, one of the wirings can be omitted. It may be omitted. Also, if the same potential is supplied to wiring 122 and wiring 124, either one One of the wires may be omitted. The semiconductor device 100a shown in Figure 1(B) has transistor 1 One of the sources or drains of transistor 11 and one of the sources or drains of transistor 113 The wire 121 is electrically connected to the other wire. Also, the source or the source of transistor 112 The other side of the rain and the other side of the source or drain of transistor 114 are connected to wiring 122 and electrical They are directly connected.

[0047] Furthermore, as shown in the semiconductor device 100b in Figure 1(C), the first gate of transistor 112 Alternatively, one of the second gates may be electrically connected to wiring 122. Transistor 114 Either the first gate or the second gate may be electrically connected to wiring 124. Transis Either the first gate or the second gate of transistor 111 and the first gate of transistor 113 or One side of the second gate may be electrically connected to the wiring 125. Note that the wiring 125 may include, for example For example, a potential equivalent to that of VSS, or wiring 122 or wiring 124 is supplied.

[0048] Furthermore, if necessary, some or all of the transistors included in the semiconductor device 100 may be replaced. It is also possible to use a transistor that does not use a back gate. The circuit diagram of semiconductor device 100, which is composed of ZISTAS, is shown in Figure 1(D) as semiconductor device 100c. show.

[0049] Furthermore, OS transistors are used for transistors 111 to 114. This is preferable. Since the band gap of the oxide semiconductor is 2eV or more, the OS transistor is This allows for extremely small off-currents. Specifically, the voltage between the source and drain is At 3.5V and room temperature (25°C), the off-current per 1 μm of channel width is 1 × 10⁻¹⁶. - 20 Less than A, 1 × 10 -22 Less than A, or 1 × 10 -24 It can be less than A. In other words, the on / off ratio can be set to between 20 and 150 digits. Also, OS Tra The transistor has a high dielectric strength between the source and drain. By using an OS transistor, We can provide semiconductor devices for high-power applications.

[0050] <<Example of operation of semiconductor device 100>> The semiconductor device 100 can function as an inverter circuit. Specifically, terminal 1 When an H potential is input to terminal 02, an L potential is output from terminal 105, and when an L potential is input to terminal 102... When power is applied, a high potential is output from terminal 105.

[0051] Regarding the operation example of semiconductor device 100, see the timing chart in Figure 2 and the rotations in Figures 3 and 4. This will be explained using a circuit diagram. Also, wires 121 and 123 are supplied with a high potential (VDD). Furthermore, it is assumed that an L potential (VSS) is supplied to wiring 122 and wiring 124. Furthermore, the threshold voltages of transistors 111 to 114 are all the same, as specified herein. In such cases, it is indicated as "Vth". Also, Vth is greater than 0 volts, and (VDD-V The SS) / 2 must be less than 2.

[0052] [Period 151: H potential input period] During period 151, when a high potential is input to terminal 102, node 132 becomes high potential. Transistors 112 and 114 turn on. Then node 131 and Node 133 becomes L potential, and transistor 113 turns OFF. Also, node 1 An L potential is output from terminal 105, which is electrically connected to 33 (see Figure 3(A)).

[0053] Transistors 111 and 112 are turned on simultaneously. Therefore, node 13 To bring the potential of 1 closer to the L potential, the on-resistance of transistor 112 (transistor is on) The resistance between the source and drain when the transistor is in the ON state. (This value is greater than the ON resistance of transistor 111.) It is preferable to lower it. For example, the channel length of transistor 112 is lowered. It should be shorter than the channel length of 11. Specifically, the channel length of transistor 112. The channel length of transistor 111 is less than or equal to 1 / 2, preferably less than or equal to 1 / 5, more preferably less than or equal to 1 / 5. It should be 1 / 10 or less, more preferably 1 / 20 or less. Also, for example, Trans The channel width of transistor 112 should be made longer than the channel width of transistor 111. Specifically, the channel width of transistor 112 is set to twice the channel width of transistor 111. Preferably, it should be 5 times or more, more preferably 10 times or more, and even more preferably 20 times or more. This is sufficient. Also, for example, if transistor 112 is a transistor with a back gate Alternatively, a transistor without a back gate may be used for transistor 111.

[0054] [Period 152: L potential input period] During period 152, when an L potential is input to terminal 102, node 132 becomes L potential. Transistors 112 and 114 turn off. Then, from wiring 121, Potential is supplied to node 131 via transistor 111. At this time, the electric current of node 131 The position is VDD-Vth (see Figure 3(B)).

[0055] Furthermore, since the potential at node 131 is greater than Vth, transistor 113 is turned ON. (See Figure 3(B)). Then, from wiring 123 to node 1 via transistor 113 A potential is supplied to node 33 (see Figure 4(A)). At this time, the potential at node 133 is VDD. -Vth

[0056] When potential is supplied to node 133, node 131, which is coupled via capacitive element 117, The potential increases. Specifically, the potential at node 131 becomes 2 × (VDD - Vth). Furthermore, the potential of node 133 will eventually become equal to that of wiring 123. Therefore, the potential of node 131 The position rises to the vicinity of 2 × VDD - Vth. Therefore, transistor 111 is in the off state. Yes. Also, a high potential (VDD) is output from terminal 105 (see Figure 4(B)).

[0057] <Example 1> Figure 5(A) shows a circuit diagram of semiconductor device 110, which has a different configuration from semiconductor device 100. The semiconductor device 110 includes transistors 111 to 113, and a capacitive element 1 It has 17. The semiconductor device 110 is composed of fewer transistors than the semiconductor device 100. Therefore, the occupied area can be reduced compared to the semiconductor device 100. To avoid repetition, I will mainly explain the differences from semiconductor device 100.

[0058] <<Example configuration of semiconductor device 110>> In the semiconductor device 110 shown in Figure 5(A), the source or drain of the transistor 111 One end of the input is electrically connected to wiring 121, the other end is either source or drain, and the first The first gate is electrically connected to node 131, and the second gate is electrically connected to node 133. It is also connected to node 131. One is electrically connected to the other, which is electrically connected to wiring 122, and the first gate and the second gate It is electrically connected to terminal 102. Also, the source or dot of transistor 113 One end of the rain is electrically connected to terminal 106, and the other end of the source or drain is connected to node 1 33 is electrically connected, and the first and second gates are electrically connected to wiring 123. Furthermore, one electrode of the capacitive element 117 is electrically connected to node 131 and the other electrode is electrically connected to node 131. The pole is electrically connected to node 133. Also, node 131 is electrically connected to terminal 105. Connected.

[0059] Furthermore, if the same potential is supplied to both wiring 121 and wiring 123, one of the wirings can be omitted. This may be omitted. The semiconductor device 110a shown in Figure 5(B) is the first gate of transistor 113. The first gate and the second gate are electrically connected to the wiring 121.

[0060] Also, as shown in Figure 5(C) of semiconductor device 110b, the first gate of transistor 112 Alternatively, one of the second gates may be electrically connected to wiring 122. Transistor 113 Either the first gate or the second gate may be electrically connected to the wiring 124. VSS will be supplied to the 124.

[0061] Furthermore, if necessary, at least one of transistors 112 or 113 may be used. It is also possible to use transistors that do not use a back gate. Transistor 112 and Semiconductor device 1 in which both transistors 113 are transistors without back gates Circuit diagram 10 is shown in Figure 5(D) as semiconductor device 110c.

[0062] <<Example of operation of semiconductor device 110>> The semiconductor device 110 can function as an inverter circuit. Specifically, terminal 1 When an H potential is input to terminal 02, an L potential is output from terminal 105, and when an L potential is input to terminal 102... When power is applied, a high potential is output from terminal 105.

[0063] Furthermore, different potentials are supplied to terminals 102 and 106. Specifically, terminals When supplying a high potential to terminal 102, a low potential is supplied to terminal 106. When supplying power, a high potential is supplied to terminal 106.

[0064] Regarding the operation example of the semiconductor device 110, see the timing chart in Figure 6 and the rotations in Figures 7 and 8. I will explain using a road map.

[0065] [Period 151: H potential input period] During period 151, a high potential is input to terminal 102 and a low potential is input to terminal 106. Then, transistors 112 and 113 turn on, and node 131 An L potential is supplied to node 133. Also, the terminals electrically connected to node 131. An L potential is output from 105 (see Figure 7(A)).

[0066] In semiconductor device 110, transistors 111 and 112 are turned ON simultaneously. This does not occur. Therefore, the transistor 111 and transistor in the semiconductor device 100 There are no restrictions regarding the on-resistance of 112.

[0067] [Period 152: L potential input period] During period 152, an L potential is input to terminal 102 and an H potential is input to terminal 106. Then, transistor 112 turns off. Also, via transistor 113, the node Potential is supplied to terminal 133 from terminal 106. At this time, the gate of transistor 113 is wired. Since a high potential (VDD) is supplied from node 123, the potential at node 131 is VDD-Vt The value becomes h (see Figure 7(B)).

[0068] Furthermore, since the potential of node 133 is greater than Vth, transistor 111 is turned ON. (See Figure 7(B).) Then, from wiring 121 to node 1 via transistor 111 Potential is supplied to 31.

[0069] When potential is supplied to node 131, node 133, which is coupled via capacitive element 117, The potential increases. Eventually, the potential at node 133 rises to near 2 × VDD - Vth. Therefore, transistor 113 is in the off state. Also, a high potential (VD) is emitted from terminal 105. D) is output (see Figure 8).

[0070] <Modification 2> Figure 9(A) shows the circuit diagram of a semiconductor device with even fewer transistors than semiconductor device 110. As shown in Figure 9(A), the semiconductor device 120 includes transistor 111 and transistor It has 112. The semiconductor device 120 is constructed with fewer transistors than the semiconductor device 110. Therefore, the occupied area can be reduced compared to the semiconductor device 110.

[0071] <<Example configuration of semiconductor device 120>> In the semiconductor device 120 shown in Figure 9(A), the source or drain of the transistor 111 One end of the input is electrically connected to wiring 125, the other to source or drain, and the first The first gate is electrically connected to node 131, and the second gate is electrically connected to terminal 103. Furthermore, one of the sources or drains of transistor 112 is connected to node 131. One end is electrically connected to the other, and the other end is electrically connected to wiring 123, and the first gate or the second gate One end is electrically connected to terminal 102, and the other end of the first or second gate is connected to terminal 104. It is electrically connected to it. Also, node 131 is electrically connected to terminal 105. .

[0072] Also, as shown in the semiconductor device 120a in Figure 9(B), the first gate of transistor 112 Either the first or second gate may be electrically connected to the wiring 123. Semiconductor device 120a Compared to semiconductor device 120, the number of input terminals can be reduced, thus the semiconductor device Productivity can be improved.

[0073] <<Example of operation of semiconductor device 120>> The semiconductor device 120 can function as an inverter circuit. Specifically, terminal 1 When a high potential is input to terminals 02 and 104, and a low potential is input to terminal 103, terminal 10 An L potential is output from terminal 5. Also, an L potential is input to terminals 102 and 104, and terminal When a high potential is input to terminal 103, VDD-Vth is output from terminal 105. To output a high potential from sub-unit 105, a potential greater than or equal to VDD + Vth must be applied to terminal 103. Just do your best.

[0074] <Variation 3> Figure 9(C) shows the circuit diagram of a semiconductor device with even fewer transistors than semiconductor device 110. As shown in Figure 9(C), the semiconductor device 130 is composed of transistor 111 and transistor It has 112. The semiconductor device 130 is constructed with fewer transistors than the semiconductor device 110. Therefore, the occupied area can be reduced compared to the semiconductor device 110.

[0075] <<Example configuration of semiconductor device 130>> In the semiconductor device 130 shown in Figure 9(C), the source or drain of the transistor 111 One end of the input is electrically connected to wiring 125, and the other end of the source or drain is connected to node 13. It is electrically connected to 1, and either the first gate or the second gate is electrically connected to terminal 101. The other of the first gate or the second gate is electrically connected to terminal 103. One of the sources or drains of transistor 112 is electrically connected to node 131. The other end is electrically connected to wiring 123, and either the first gate or the second gate is connected to terminal 1 It is electrically connected to 02, and the other of the first gate or the second gate is electrically connected to terminal 104. It is connected. Also, node 131 is electrically connected to terminal 105.

[0076] Also, as shown in the semiconductor device 130a in Figure 9(D), the first gate of transistor 111 Either the first or second gate may be electrically connected to the wiring 123. Transistor 112 Either the first gate or the second gate may be electrically connected to the wiring 123. Since the device 130a can reduce the number of input terminals compared to the semiconductor device 130, This can improve the productivity of semiconductor devices.

[0077] <<Example of operation of semiconductor device 130>> The semiconductor device 130 can function as an inverter circuit. Specifically, terminal 1 A high potential is input to terminals 02 and 104, and a low potential is input to terminals 101 and 103. When this happens, an L potential is output from terminal 105. Also, an L potential is output from terminals 102 and 104. When a position is input and a high potential is input to terminals 101 and 103, VD is input from terminal 105. D-Vth is output. Note that in order to output a high potential from terminal 105, terminal 10 Simply input a potential of VDD+Vth or higher to terminals 1 and 103.

[0078] This embodiment can be implemented in appropriate combination with the configurations described in other embodiments. That is the case.

[0079] (Embodiment 2) In this embodiment, the transistors that can be used in the semiconductor device shown in the above embodiment Here is an example of a "ta" (a type of character).

[0080] A semiconductor device according to one aspect of the present invention includes a bottom-gate type transistor and a top-gate type transistor. It can be fabricated using various types of transistors, such as radiators. Therefore, existing The semiconductor layer materials and transistor structures used can be easily replaced to match the manufacturing line. It is possible.

[0081] [Bottom-gate transistor] Figure 10(A1) shows a channel-protected transistor, which is a type of bottom-gate transistor. This is a cross-sectional view of transistor 410. Transistor 410 is connected to substrate 271 via an insulating layer 272. It has an electrode 246. Furthermore, a semiconductor layer 242 is placed on the electrode 246 via an insulating layer 226. It has. Electrode 246 can function as a gate electrode. Insulating layer 226 as a gate insulating layer It can function.

[0082] Furthermore, an insulating layer 225 is provided on the channel formation region of the semiconductor layer 242. Electrodes 244a and 244b are located on the insulating layer 226, in contact with a portion of 42. A portion of 244a and a portion of electrode 244b are formed on the insulating layer 225.

[0083] The insulating layer 225 can function as a channel protection layer. The insulating layer 225 is placed on the channel formation region. By providing this, the dew on the semiconductor layer 242 that occurs when electrodes 244a and 244b are formed. This prevents leakage. Therefore, when forming electrodes 244a and 244b, the semiconductor layer This prevents the 242 channel formation regions from being etched. One aspect of the present invention According to this, it is possible to realize transistors with good electrical characteristics.

[0084] Furthermore, the transistor 410 has an insulating layer 225 on electrode 244a, electrode 244b and insulating layer 225. It has a layer 228, and an insulating layer 229 on top of the insulating layer 228.

[0085] Furthermore, when an oxide semiconductor is used for the semiconductor layer 242, electrodes 244a and 244b At least in the portion in contact with the semiconductor layer 242, oxygen is removed from a part of the semiconductor layer 242, and acid It is preferable to use a material capable of causing elementary defects. Oxygen in semiconductor layer 242 In the region where the defect occurs, the carrier concentration increases, and the region becomes n-type, and the n-type region (n + (layers) and Therefore, the region can function as either a source region or a drain region. As an example of a material that can have oxygen removed from an oxide semiconductor, thereby creating an oxygen vacancy, Examples include tungsten and titanium.

[0086] By forming a source region and a drain region in the semiconductor layer 242, the electrode 244a Furthermore, the contact resistance between electrode 244b and semiconductor layer 242 can be reduced. Therefore, the electric field The goal is to improve the electrical characteristics of the transistor, such as effective mobility and threshold voltage. can.

[0087] When a semiconductor such as silicon is used for the semiconductor layer 242, the semiconductor layer 242 and electrode 244a Between the semiconductor layer 242 and the electrode 244b, as an n-type semiconductor or a p-type semiconductor It is preferable to provide a functional layer. The layer that functions as an n-type semiconductor or a p-type semiconductor is It can function as either the source or drain region of a transistor.

[0088] The insulating layer 229 has the function of preventing or reducing the diffusion of impurities from the outside into the transistor. It is preferable to form it using a material having the following properties. The insulating layer 229 may be omitted if necessary. It is also possible.

[0089] Furthermore, when an oxide semiconductor is used for the semiconductor layer 242, before or after the formation of the insulating layer 229. Alternatively, heat treatment may be performed before or after the formation of the insulating layer 229. By performing heat treatment, Oxygen contained in the insulating layer 229 and other insulating layers is diffused into the semiconductor layer 242, and the semiconductor layer 2 The oxygen deficiency in 42 can be compensated for. Alternatively, the insulating layer 229 can be formed while heating. This makes it possible to compensate for oxygen vacancies in the semiconductor layer 242.

[0090] The transistor 411 shown in Figure 10(A2) functions as a back gate on the insulating layer 229. It differs from transistor 410 in that it has an electrode 223. Electrode 223 is the same as electrode 246. It can be formed using the same materials and methods as above.

[0091] <About the back gate> Generally, the back gate is formed in a conductive layer, and the gate and back gate form a channel in the semiconductor layer. It is positioned to sandwich the formation region. Therefore, the back gate functions in the same way as the gate. This is possible. The potential of the back gate may be the same as the gate potential, or it may be the GND potential, The potential can be any value. Furthermore, the potential of the back gate can be changed independently of the gate. By doing so, the threshold voltage of the transistor can be changed.

[0092] Both electrodes 246 and 223 can function as gates. Therefore, Insulating layer 226, insulating layer 225, insulating layer 228, and insulating layer 229 are each gate It can function as an insulating layer. Furthermore, electrode 223 is connected to insulating layer 228 and insulating layer 229 It may be placed between them.

[0093] Note that one of the electrodes 246 or 223 is referred to as the "gate" or "gate electrode". The other side is called the "back gate" or "back gate electrode." For example, a transistor. In 411, when electrode 223 is referred to as the "gate electrode," electrode 246 is referred to as the "back gate electrode." It is called an "electrode". Note that when electrode 223 is used as a "gate electrode", transistor 4 11 can be considered a type of top-gate transistor. Also, electrode 246 One of the electrodes 223 is called the "first gate" or "first gate electrode," and the other This is sometimes referred to as the "second gate" or "second gate electrode."

[0094] By providing electrodes 246 and 223 with the semiconductor layer 242 in between, further, electrode 24 By setting electrode 6 and electrode 223 to the same potential, the carrier flow region in semiconductor layer 242 As the region becomes larger in the film thickness direction, the amount of carrier movement increases. As a result, As the on-current of the transistor 411 increases, the field-effect mobility also increases.

[0095] Therefore, transistor 411 has a large on-current relative to its occupied area. It is a transistor. In other words, the area occupied by transistor 411 is relative to the required on-current. It can be made smaller. According to one aspect of the present invention, the area occupied by the transistor can be reduced. Therefore, according to one aspect of the present invention, a semiconductor device with a high degree of integration can be realized. It is possible.

[0096] Furthermore, since the gate and back gate are formed of conductive layers, the electric current generated outside the transistor A function that prevents the field from acting on the semiconductor layer in which the channel is formed (especially against static electricity, etc.) It has an electric field shielding function. Furthermore, the back gate is formed to be larger than the semiconductor layer, By covering the semiconductor layer with a gate, the electric field shielding function can be enhanced.

[0097] Furthermore, electrode 246 (gate) and electrode 223 (back gate) are each externally controlled Because it has the function of shielding the electric field, the load generated on the insulating layer 272 side or above the electrode 223 The electric charge of electron particles, etc., does not affect the channel formation region of the semiconductor layer 242. As a result, stress Test (for example, applying a negative charge to the gate of an NGBT (Negative Gate B) IAS-Temperature stress test (also known as "NBT" or "NBTS") Degradation due to ( ) is suppressed. Also, the on current flows depending on the magnitude of the drain voltage. This can reduce the phenomenon of changes in the gate voltage (on-start voltage) at which the voltage begins to rise. This effect occurs when electrodes 246 and 223 are at the same potential or different potentials. To occur.

[0098] Furthermore, transistors with a back gate are PGBT(P) which apply a positive charge to the gate. (Positive Gate Bias-Temperature) Stress Test ("PB Also called "T" or "PBTS". ) The fluctuation of the threshold voltage before and after is also a backgate. It is smaller than a transistor that does not have this feature.

[0099] Note that BT stress tests such as NGBT and PGBT are a type of accelerated stress test, and over a long period of time... It is possible to quickly evaluate the characteristic changes (aging) of transistors caused by their use. It is possible. In particular, the amount of change in the threshold voltage of the transistor before and after the BT stress test is reliable. This is an important indicator for examining reliability. The smaller the fluctuation in threshold voltage, the higher the reliability. It can be said that it is a transistor.

[0100] Furthermore, it has electrodes 246 and 223, and electrodes 246 and 223 are at the same potential. This reduces the fluctuation in the threshold voltage. Therefore, in multiple transistors... The variation in electrical characteristics is also reduced at the same time.

[0101] Furthermore, by forming the back gate with a light-shielding conductive film, half of the back gate can be exposed. This prevents light from entering the conductive layer. Therefore, it prevents photodegradation of the semiconductor layer and reduces the risk of light entering the conductive layer. This prevents deterioration of electrical characteristics, such as a shift in the threshold voltage of the inverter.

[0102] According to one aspect of the present invention, a transistor with good reliability can be realized. Furthermore, This enables the creation of highly reliable semiconductor devices.

[0103] Figure 10(B1) shows a channel-protected transistor, which is a type of bottom-gate transistor. A cross-sectional view of transistor 420 is shown. Transistor 420 is almost the same as transistor 410. It has a structure, but differs in that the insulating layer 225 covers the semiconductor layer 242. Insulating layer 2 By providing 25, the semiconductor layer 242 that is formed when electrodes 244a and 244b are formed This prevents exposure of the semiconductor when forming electrodes 244a and 244b. This prevents the thinning of layer 242.

[0104] Furthermore, in the opening formed by selectively removing a portion of the insulating layer 225 that overlaps with the semiconductor layer 242, In this configuration, the semiconductor layer 242 and the electrode 244a are electrically connected. In another opening formed by selectively removing a portion of the insulating layer 225 that overlaps with the semiconductor layer, 242 and electrode 244b are electrically connected. The channel formation region of the insulating layer 225 overlaps with the surrounding area. This region can function as a channel protection layer.

[0105] The transistor 421 shown in Figure 10(B2) functions as a back gate on the insulating layer 229. It differs from transistor 420 in that it has a capable electrode 223.

[0106] Furthermore, transistors 420 and 421 are transistors 410 and 421. The distance between electrode 244a and electrode 246, and between electrode 244b and electrode 2 The distance between 46 increases. Therefore, the parasitic capacitance that occurs between electrode 244a and electrode 246 It can be made smaller. Also, the parasitic capacitance that occurs between electrode 244b and electrode 246 can be reduced. This can be achieved. According to one aspect of the present invention, a transistor with good electrical characteristics can be realized. Cut.

[0107] The transistor 425 shown in Figure 10(C1) is a type of bottom-gate transistor. This is a channel-etched transistor. Transistor 425 has an insulating layer 225. Without providing a separate electrode, electrodes 244a and 244b are formed in contact with the semiconductor layer 242. Therefore, when electrodes 244a and 244b are formed, a portion of the semiconductor layer 242 that is exposed is etched. It may be ringed. On the other hand, since the insulating layer 225 is not provided, the productivity of the transistor can be increased. It can be improved.

[0108] ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​This can be done using a scientific apparatus.

[0112] As impurities 255, for example, at least one of the elements from Group 13 or Group 15. Various elements can be used. Also, when an oxide semiconductor is used for the semiconductor layer 242 As impurity 255, at least one element from among noble gases, hydrogen, and nitrogen is used. It is possible to be there.

[0113] The transistor 431 shown in Figure 11(A2) has an electrode 223 and an insulating layer 227. This is different from transistor 430. Transistor 431 is formed on the insulating layer 272 It has an electrode 223 and an insulating layer 227 formed on the electrode 223. It can function as a gate. Therefore, the insulating layer 227 is a gate insulating layer. It can function. The insulating layer 227 is formed using the same materials and methods as the insulating layer 226. It is possible.

[0114] Similar to transistor 411, transistor 431 has a large on-current relative to its occupied area. This is a transistor having the following characteristics: That is, for the required on-current, transistor 4 The occupied area of ​​31 can be reduced. According to one aspect of the present invention, the occupancy area of ​​the transistor The surface area can be reduced. Therefore, according to one aspect of the present invention, a semiconductor with a high degree of integration A physical device can be realized.

[0115] The transistor 440 shown in Figure 11(B1) is a top-gate type transistor. The transistor 440 is a semiconductor after forming electrodes 244a and 244b. The difference from transistor 430 is that it forms layer 242. Also, as illustrated in Figure 11(B2)... The transistor 441 has an electrode 223 and an insulating layer 227, which is the same as transistor 4 It is different from 40. In transistors 440 and 441, semiconductor layer 242 A portion of the semiconductor layer 242 is formed on electrode 244a, and the other portion of the semiconductor layer 242 is formed on electrode 244b. It will be done.

[0116] Similar to transistor 411, transistor 441 has a large on-current relative to its occupied area. This is a transistor having the following characteristics: That is, for the required on-current, transistor 4 The occupied area of ​​41 can be reduced. According to one aspect of the present invention, the occupancy area of ​​the transistor The surface area can be reduced. Therefore, according to one aspect of the present invention, a semiconductor with a high degree of integration A physical device can be realized.

[0117] The transistor 442 shown in Figure 12(A1) is a top-gate type transistor. The transistor 442 has electrodes 244a and 244b on the insulating layer 229. Electrodes 244a and 244b are formed in insulating layers 228 and 229. The opening is electrically connected to the semiconductor layer 242.

[0118] Furthermore, a portion of the insulating layer 226 that does not overlap with electrode 246 has been removed. A portion of the insulating layer 226 of the 442 extends beyond the end of the electrode 246.

[0119] The impurities 255 are introduced into the semiconductor layer 242 using the electrode 246 and the insulating layer 226 as a mask. By doing so, impurity regions are formed in the semiconductor layer 242 in a self-aligned manner. This is possible (see Figure 12(A3)).

[0120] At this time, impurities 255 are not introduced into the region overlapping with the electrode 246 of the semiconductor layer 242, and impurities 255 are introduced into the region not overlapping with the electrode 246. Further, the impurity concentration of the region where impurities 255 are introduced through the insulating layer 2 26 of the semiconductor layer 242 is lower than that of the region where impurities 255 are introduced without passing through the insulating layer 226. Therefore, a lightly doped drain (LDD) region is formed in the region adjacent to the electrode 246 in the semiconductor layer 242.

[0121] The transistor 443 shown in FIG. 12(A2) is different from the transistor 442 in that it has an electrode 223 below the semiconductor layer 242. Also, the electrode 223 overlaps the semiconductor layer 242 through the insulating layer 272. The electrode 223 can function as a back gate electrode.

[0122] Also, as in the transistor 444 shown in FIG. 12(B1) and the transistor 445 shown in FIG. 12(B2), all regions of the insulating layer 226 that do not overlap with the electrode 246 may be removed. Also, as in the transistor 446 shown in FIG. 12(C1) and the transistor 447 shown in FIG. 12(C2), the portions other than the openings of the insulating layer 226 may be left without being removed.

[0123] For the transistors 444 to 447 as well, after forming the electrode 246, impurities 255 are introduced into the semiconductor layer 242 using the electrode 246 as a mask, so that impurity regions can be self-alignedly formed in the semiconductor layer 242.

[0124] 〔s-channel type transistor〕 FIG. 13 shows an example of a transistor structure using an oxide semiconductor as the semiconductor layer 242. The transistor 450 illustrated in FIG. 13 has a semiconductor layer 242b formed on the semiconductor layer 242a. The upper surface of semiconductor layer 242b and the sides of semiconductor layer 242a and semiconductor layer 242b are formed. It has a structure covered with a semiconductor layer 242c. Figure 13(A) is a top view of transistor 450. Figure 13(B) is a cross-sectional view of the area indicated by the dashed line X1-X2 in Figure 13(A). (Cross-sectional view in the channel length direction). Figure 13(C) is a section of Y1-Y2 in Figure 13(A). This is a cross-sectional view of the area indicated by the dashed line (cross-sectional view in the channel width direction).

[0125] Furthermore, transistor 450 has an electrode 243 that functions as a gate electrode. 3 can be formed using the same materials and methods as electrode 246. In this embodiment, Electrode 243 is constructed as a stack of two conductive layers.

[0126] Semiconductor layer 242a, semiconductor layer 242b, and semiconductor layer 242c are made of In or Ga Formed from a material containing one or both of the following: Typically, In-Ga oxide (In and Ga (Oxides containing), In-Zn oxide (Oxides containing In and Zn), In-M-Zn oxide ( An oxide containing In, element M, and Zn. Element M can be Al, Ti, Ga, Y, Zr, La, One or more elements selected from Ce, Nd, or Hf, with a stronger bond to oxygen than In. It is a metallic element.

[0127] Semiconductor layer 242a and semiconductor layer 242c are composed of metal elements that make up semiconductor layer 242b It is preferable that it be formed from a material containing one or more of the same metallic elements. When the material is used, the interface between semiconductor layer 242a and semiconductor layer 242b, and the semiconductor layer This makes it less likely for interface states to form at the interface between 242c and the semiconductor layer 242b. Therefore, carrier scattering and trapping at the interface are less likely to occur, and the field-effect mobility of the transistor is reduced. This makes it possible to improve the performance. Furthermore, it reduces variations in the transistor threshold voltage. This makes it possible to realize semiconductor devices with good electrical characteristics. This is the result.

[0128] The thickness of semiconductor layer 242a and semiconductor layer 242c is preferably between 3 nm and 100 nm. The thickness shall be between 3 nm and 50 nm. Also, the thickness of semiconductor layer 242b shall be between 3 nm and 20 nm. 0 nm or less, preferably 3 nm to 100 nm, more preferably 3 nm to 50 nm Let m be less than or equal to m.

[0129] Furthermore, semiconductor layer 242b is In-M-Zn oxide, and semiconductor layer 242a and semiconductor When layer 242c is also an In-M-Zn oxide, semiconductor layer 242a and semiconductor layer 242 c is In:M:Zn=x1:y1:z1 [atomic ratio], and semiconductor layer 242b is In:M:Z If n = x²:y²:z² [atomic ratio], then y1 / x1 will be greater than y² / x². The semiconductor layer 242a, semiconductor layer 242c, and semiconductor layer 242b can be selected in this way. Yes, it is possible. Preferably, the semiconductor is such that y1 / x1 is at least 1.5 times larger than y2 / x2. A body layer 242a, a semiconductor layer 242c, and a semiconductor layer 242b are selected. More preferably The semiconductor layer 242a and semiconductor are configured such that y1 / x1 is more than twice as large as y2 / x2. Select layer 242c and semiconductor layer 242b. More preferably, y1 / x1 is equal to y2 / Semiconductor layer 242a, semiconductor layer 242c and semiconductor so that it is more than 3 times larger than x2. Select layer 242b. If y1 is greater than or equal to x1, it provides stable electrical characteristics to the transistor. This is preferable because it allows for this. However, when y1 becomes more than three times x1, the field effect of the transistor... Since mobility decreases, it is preferable that y1 is less than 3 times x1. Semiconductor layer 242 By configuring a and semiconductor layer 242c as described above, the semiconductor layer 242a and semiconductor Layer 242c can be made into a layer that is less prone to oxygen vacancies than semiconductor layer 242b.

[0130] Furthermore, when semiconductor layer 242a and semiconductor layer 242c are In-M-Zn oxide, I When the sum of n and element M is set to 100 atomic%, the atomic ratio of In to element M is: Preferably, In is less than 50 atomic%, and element M is 50 atomic or more, even more preferably In addition, the concentration of In is less than 25 atomic%, and the concentration of element M is 75 atomic%, or more. When semiconductor layer 242b is In-M-Zn oxide, the sum of In and element M is 100. When expressed as atomic%, the atomic ratio of In to element M is preferably 25 atoms for In. 1% or more, element M less than 75 atomic%, and more preferably In 34 atomic% The concentration must be c% or greater, and element M must be less than 66 atomically.

[0131] For example, a semiconductor layer 242a containing In or Ga, and a semiconductor layer containing In or Ga For 242c, In:Ga:Zn = 1:3:2, 1:3:4, 1:3:6, 1:4:5. In-Ga formed using targets with atomic ratios such as 1:6:4 or 1:9:6 -In formed using Zn oxide or targets with atomic ratios such as In:Ga=1:9 -Ga oxide and gallium oxide can be used. Also, the semiconductor layer 242b In:Ga:Zn = 3:1:2, 1:1:1, 5:5:6, 5:1:7, or 4:2 Use an In-Ga-Zn oxide formed using a target of an atomic ratio such as 4.1 This is possible. Note that the atomic ratios of the semiconductor layer 242a, the semiconductor layer 242b, and the semiconductor layer 242c each include fluctuations of plus or minus 20% of the above atomic ratio as an error.

[0132] In order to impart stable electrical characteristics to the transistor using the semiconductor layer 242b, impurities and oxygen deficiencies in the semiconductor layer 242b are reduced to achieve high purity intrinsic properties, and it is preferable that the semiconductor layer 242b be an oxide semiconductor layer that can be regarded as having high purity intrinsic properties or substantially high purity intrinsic properties. Also, preferably, at least the channel formation region in the semiconductor layer 242b is a semiconductor layer that can be regarded as having high purity intrinsic properties or substantially high purity intrinsic properties.

[0133] Note that an oxide semiconductor layer that can be regarded as substantially having high purity intrinsic properties means that the carrier density in the oxide semiconductor layer is less than 8×10 11 / cm 3 preferably less than 1×10 11 / cm 3 and more preferably less than 1×10 10 / cm 3 and greater than or equal to 1×10 -9 / cm 3 This refers to an oxide semiconductor layer.

[0134] FIG. 14 shows an example of a transistor structure using an oxide semiconductor as the semiconductor layer 242. The transistor 422 illustrated in FIG. 14 has a semiconductor layer 242b formed on the semiconductor layer 242a. The transistor 422 is a type of bottom gate transistor having a back gate. FIG. 14(A) is a top view of the transistor 4:22. FIG. 14(B) is ... , Cross-sectional view of the area indicated by the dashed line X1-X2 in Figure 14(A) (Cross-section in the direction of the channel length) Figure 14(C) shows a cross-section of the area indicated by the dashed line Y1-Y2 in Figure 14(A). This is a top view (cross-sectional view in the channel width direction).

[0135] The electrode 223 provided on the insulating layer 229 is located on the insulating layer 226, insulating layer 228, and insulating layer In the openings 247a and 247b provided in 229, the electrode 246 is electrically connected It is connected. Therefore, the same potential is supplied to electrode 223 and electrode 246. Also, open Either opening 247a or opening 247b does not need to be provided. It is not necessary to provide both opening a and opening 247b. If no such method is provided, different potentials can be supplied to electrode 223 and electrode 246.

[0136] [Energy band structure of oxide semiconductors] Here, the semiconductor layer 242a, semiconductor layer 242b, and semiconductor layer 242c are stacked to form The function and effects of the resulting semiconductor layer 242 are shown in Figures 20(A) and 20(B). This will be explained using the energy band structure diagram shown in Figure 20(A). Figure 20(A) is the same as Figure 13(B) but with D This is an energy band structure diagram of the region indicated by the dashed line 1-D2. Figure 20(A) shows the tra This shows the energy band structure of the channel formation region of the 450 element.

[0137] In Figure 20(A), Ec382, Ec383a, Ec383b, Ec383c, Ec386 These are the insulating layer 272, semiconductor layer 242a, semiconductor layer 242b, and semiconductor layer 242c, respectively. This shows the energy at the lower end of the conduction band of the insulating layer 226.

[0138] Here, the difference between the energy of the vacuum level and the energy of the lower end of the conduction band (also called "electron affinity") is true The difference between the energy of the empty level and the energy of the upper end of the valence band (also called the ionization potential) This is the value after subtracting the energy gap. Note that the energy gap is measured using a spectroscopic ellipsometer. For example, it can be measured using a HORIBA JOBIN YVON UT-300. Furthermore, the energy difference between the vacuum level and the upper end of the valence band can be determined by ultraviolet photoelectron spectroscopy (UPS:Ul Traviolet Photoelectron Spectroscopy device For example, it can be measured using PHI's VersaProbe.

[0139] Furthermore, In-G was formed using a target with an atomic ratio of In:Ga:Zn=1:3:2. The energy gap of α-Zn oxide is approximately 3.5 eV, and the electron affinity is approximately 4.5 eV. Furthermore, In- formed using a target with an atomic ratio of In:Ga:Zn=1:3:4 The energy gap of Ga-Zn oxide is approximately 3.4 eV, and the electron affinity is approximately 4.5 eV. Furthermore, In formed using a target with an atomic ratio of In:Ga:Zn=1:3:6 The energy gap of Ga-Zn oxide is approximately 3.3 eV, and the electron affinity is approximately 4.5 eV. Yes. Also, I formed using a target with an atomic ratio of In:Ga:Zn=1:6:2 The energy gap of n-Ga-Zn oxide is approximately 3.9 eV, and its electron affinity is approximately 4.3 eV. Furthermore, a target with an atomic ratio of In:Ga:Zn=1:6:8 was formed. The energy gap of In-Ga-Zn oxide is approximately 3.5 eV, and its electron affinity is approximately 4.4 eV. It is V. Furthermore, it is formed using a target with an atomic ratio of In:Ga:Zn = 1:6:10. The energy gap of the resulting In-Ga-Zn oxide is approximately 3.5 eV, and its electron affinity is approximately 4. It is 5 eV. Also, using a target with an atomic ratio of In:Ga:Zn=1:1:1, the shape The resulting In-Ga-Zn oxide has an energy gap of approximately 3.2 eV and an electron affinity of approximately 4 It is 0.7eV. Also, using a target with an atomic ratio of In:Ga:Zn=3:1:2 The energy gap of the formed In-Ga-Zn oxide is approximately 2.8 eV, and the electron affinity is approximately It is 5.0 eV.

[0140] Since insulating layer 272 and insulating layer 226 are insulators, Ec382 and Ec386 are Ec38 It is closer to the vacuum level (lower electron affinity) than 3a, Ec383b, and Ec383c. .

[0141] Furthermore, Ec383a is closer to the vacuum level than Ec383b. Specifically, Ec383a This is 0.05eV or more, 0.07eV or more, 0.1eV or more, or 0 eV higher than Ec383b. 0.15eV or greater, and 2eV or less, 1eV or less, 0.5eV or less, or 0.4eV or less (true) It is preferable to be close to the empty level.

[0142] Furthermore, Ec383c is closer to the vacuum level than Ec383b. Specifically, Ec383c This is 0.05eV or more, 0.07eV or more, 0.1eV or more, or 0 eV higher than Ec383b. 0.15eV or greater, and 2eV or less, 1eV or less, 0.5eV or less, or 0.4eV or less (true) It is preferable to be close to the empty level.

[0143] Furthermore, near the interface between semiconductor layer 242a and semiconductor layer 242b, and with semiconductor layer 242b Near the interface with the semiconductor layer 242c, a mixed region is formed, and therefore the energy at the lower end of the conduction band - changes continuously. That is, at these interfaces, there are either no levels or very few levels. stomach.

[0144] Therefore, in the laminated structure having the energy band structure, electrons are in the semiconductor layer 242b The movement will mainly occur at the interface between the semiconductor layer 242a and the insulating layer 272. Alternatively, even if an energy level exists at the interface between the semiconductor layer 242c and the insulating layer 226, the said energy level This has almost no effect on electron movement. Also, the boundary between semiconductor layer 242a and semiconductor layer 242b There are no energy levels present on the surface, and at the interface between semiconductor layer 242c and semiconductor layer 242b, or almost none. Therefore, it does not hinder electron movement in that region. Transistors with a layered conductive structure can achieve high field-effect mobility.

[0145] Furthermore, as shown in Figure 20(A), the interface between the semiconductor layer 242a and the insulating layer 272, and the semiconductor Near the interface between the body layer 242c and the insulating layer 226, there are trap levels 39 caused by impurities and defects. Although 0 can be formed, due to the presence of semiconductor layer 242a and semiconductor layer 242c This allows the semiconductor layer 242b to be kept away from the trap level.

[0146] In particular, the transistor 134 illustrated in this embodiment has the upper and side surfaces of the semiconductor layer 242b It is formed in contact with semiconductor layer 242c, and the lower surface of semiconductor layer 242b is in contact with semiconductor layer 242a. In this way, the semiconductor layer 242b is covered by semiconductor layers 242a and 242c. By doing so, the influence of the trap level mentioned above can be further reduced.

[0147] However, in the case where the energy difference between Ec383a or Ec383c and Ec383b is small In addition, electrons in semiconductor layer 242b may exceed the energy difference and reach the trap level. . When electrons are trapped in the trap level, a negative fixed charge is generated at the interface of the insulating layer. The transistor's threshold voltage shifts in the positive direction.

[0148] Therefore, the energy difference between Ec383a and Ec383c and Ec383b is... If each is set to 0.1 eV or higher, preferably 0.15 eV or higher, the threshold voltage of the transistor Because the pressure fluctuations are reduced and the electrical characteristics of the transistor can be improved, It seems so.

[0149] Furthermore, the band gap of semiconductor layer 242a and semiconductor layer 242c is... A band gap wider than b is preferable.

[0150] Figure 20(B) shows the energy band structure of the region indicated by the dashed line D3-D4 in Figure 14(B). This is a drawing. Figure 20(B) shows the energy band of the channel formation region of transistor 422. It shows the structure.

[0151] In Figure 20(B), Ec387 represents the energy at the lower end of the conduction band of the insulating layer 228. By making the semiconductor layer 242 a two-layer semiconductor layer 242a and semiconductor layer 242b, the transient This can increase the productivity of the trap level. Although it becomes more susceptible to the influence of 390, it has a higher electric field than when semiconductor layer 242 is a single layer structure. Effective mobility can be achieved.

[0152] According to one aspect of the present invention, it is possible to realize a transistor with less variation in electrical characteristics. Therefore, it is possible to realize a semiconductor device with less variation in electrical characteristics. This invention According to one embodiment, a transistor with good reliability can be realized. Therefore, This makes it possible to realize a semiconductor device with good performance.

[0153] Furthermore, oxide semiconductors have a large energy gap of 2 eV or more, and transmit visible light through them. The rate is high. Also, in transistors obtained by processing oxide semiconductors under appropriate conditions The off-current is 100 Hz (1 × 10⁻⁶) under the operating temperature conditions (e.g., 25°C). -19 A) Less than or equal to 10zA(1×10 -20 A) Below, and furthermore, 1zA(1×1 0 -21 A) The following is possible. Therefore, to provide a semiconductor device with low power consumption. It is possible.

[0154] According to one aspect of the present invention, a transistor with low power consumption can be realized. This makes it possible to realize semiconductor devices such as display elements and display devices that consume less power. Alternatively, it is possible to realize semiconductor devices such as display elements and display devices with high reliability.

[0155] Returning to the explanation of transistor 450 shown in Figure 13, a semiconductor is placed on a protrusion provided on the insulating layer 272. By providing layer 242b, the sides of the semiconductor layer 242b can also be covered with electrodes 243. In other words, transistor 450 is affected by the electric field of electrode 243, and the semiconductor layer 242b It has a structure that can electrically surround it. In this way, the electric field of the conductive film The structure of a transistor that electrically surrounds the semiconductor layer in which the channel is formed is called surro This is called an underdated channel (s-channel) structure. A transistor having an EL structure is called an "S-channel type transistor" or "S Also known as a "-channel transistor".

[0156] In an s-channel structure, a channel is formed throughout the entire (bulk) semiconductor layer 242b. It is also possible to increase the drain current of the transistor in an s-channel structure. This allows for obtaining an even larger on-current. Also, the electric field of electrode 243 This allows for the depletion of the entire channel formation region formed in the semiconductor layer 242b. Therefore, in an s-channel structure, the off-current of the transistor can be further reduced. It is possible.

[0157] Furthermore, by increasing the height of the protrusions of the insulating layer 272 and reducing the channel width, s-cha The nnel structure can further enhance the effects of increasing on-current and reducing off-current. It is possible to remove the exposed semiconductor layer 242a when forming the semiconductor layer 242b. In this case, the sides of semiconductor layer 242a and semiconductor layer 242b may be aligned.

[0158] Furthermore, as shown in Figure 15, transistor 451 has an insulating layer below the semiconductor layer 242. Electrode 223 may be provided. Figure 15(A) is a top view of transistor 451. Figure 15(B) is a cross-sectional view of the area indicated by the dashed line X1-X2 in Figure 15(A). Figure 15(C) is a cross-sectional view of the area indicated by the dashed line Y1-Y2 in Figure 15(A).

[0159] Furthermore, as shown in the transistor 452 in Figure 16, an insulating layer 275 is provided above the electrode 243. Alternatively, layer 214 may be provided on the insulating layer 275. Figure 16(A) shows the top of transistor 452. This is a top view. Figure 16(B) is a cross-section of the area indicated by the dashed line X1-X2 in Figure 16(A). This is a top view. Figure 16(C) is a cross-section of the area indicated by the dashed line Y1-Y2 in Figure 16(A). This is a view drawing.

[0160] Note that in Figure 16, layer 214 is provided on the insulating layer 275, but it could also be on the insulating layer 228, or It may be provided on the insulating layer 229. By forming layer 214 with a light-shielding material, light This can prevent changes in transistor characteristics and a decrease in reliability caused by irradiation. Layer 214 is formed to be at least larger than semiconductor layer 242b, and layer 214 is formed to be larger than semiconductor layer 242b By covering it, the above effects can be enhanced. Layer 214 is made of organic material, inorganic material Alternatively, it can be made using a metal material. In this case, voltage may be supplied to layer 214, or it may be in an electrically floating state. You may do so.

[0161] Figure 17 shows an example of a transistor having an s-channel structure. Transistor 448 has a configuration almost identical to that of transistor 447 mentioned above. In the transistor 448, a semiconductor layer 242 is formed on a protrusion of the insulating layer 272. The 448 transistor is a type of top-gate transistor with a back gate electrode. Yes. Figure 17(A) is a top view of transistor 448. Figure 17(B) is a top view of Figure 17(A). This is a cross-sectional view of the area indicated by the dashed line between X1 and X2 in Figure 17(A). This is a cross-sectional view of the area indicated by the dashed line between Y1 and Y2.

[0162] Figure 17 shows that the semiconductor layer 242 constituting the transistor 448 is made of an inorganic semiconductor such as silicon. An example of using layers is given. In Figure 17, the semiconductor layer 242 overlaps with the gate electrode. The region has a semiconductor layer 242i, two semiconductor layers 242t, and two semiconductor layers 242u. The semiconductor layer 242i is located between the two semiconductor layers 242t. Layer 242i and the two semiconductor layers 242t are located between the two semiconductor layers 242u. .

[0163] A channel is formed in the semiconductor layer 242i when transistor 448 is ON. The semiconductor layer 242i functions as a channel formation region. Furthermore, the semiconductor layer 242t is low concentration. It functions as a low-density impurity region (LDD). In addition, the semiconductor layer 242u is a high-concentration impurity region. It functions in this way. Note that of the two semiconductor layers 242t, one or both semiconductor layers 242 It is not necessary to provide t. Also, of the two semiconductor layers 242u, one of the semiconductor layers 242u One semiconductor layer functions as the source region, while the other semiconductor layer 242u functions as the drain region.

[0164] The electrode 244a provided on the insulating layer 229 is insulated by insulating layer 226, insulating layer 228, and insulating layer 229. In the opening 247c provided in layer 229, one side of the semiconductor layer 242u is electrically connected. Furthermore, the electrode 244b provided on the insulating layer 229 is located on the insulating layer 226 and the insulating layer 2 28, and in the opening 247d provided in the insulating layer 229, the other of the semiconductor layer 242u It is electrically connected to it.

[0165] The electrode 243 provided on the insulating layer 226 is provided on the insulating layer 226 and the insulating layer 272. The openings 247a and 247b are electrically connected to the electrode 223. Therefore, the same potential is supplied to electrode 243 and electrode 223. Also, the opening 247a Opening 247a and opening 2 It is not necessary to provide both 47b and opening 247a. This configuration allows for the supply of different potentials to electrodes 223 and 243.

[0166] Figures 18(A) and 18(B) show another example of an s-channel transistor. Figure 18(A) is a plan view of transistor 473. Also, Figure 18(B) is a plan view of Figure 18 (A) Cross-sectional view of the area indicated by the dashed line L1-L2 and the area indicated by the dashed line W1-W2 In Figure 18(B), L1-L2 is the cross-section of transistor 473 in the channel length direction. This is a top view, and W1-W2 is a cross-sectional view of transistor 473 in the channel width direction.

[0167] Transistor 473 consists of a semiconductor layer 242, an insulating layer 226, an electrode 246, an electrode 244a, and It has electrode 244b. Electrode 246 can function as a gate electrode. The insulating layer 226 is It can function as an insulating layer. Electrode 244a is connected to either the source electrode or the drain electrode. It can function as such. Electrode 244b can function as either the source electrode or the other of the drain electrode. Furthermore, transistor 473 has insulating layers 273 and 272 on the substrate 271. It is provided through.

[0168] In Figure 18(B), an insulating layer 273 is provided on the substrate 271, and an insulating layer 273 is provided on the insulating layer 273. A layer 272 is provided. The insulating layer 272 has protrusions, and island-shaped semiconductor layers 24 are placed on these protrusions. 2a and island-shaped semiconductor layers 242b are provided. Also, electrodes 24 4a and electrode 244b are provided. It overlaps with electrode 244a of semiconductor layer 242b. The region can function as either the source or drain of transistor 473. Semiconductor layer The region where electrode 242b overlaps with electrode 244b is the source or drain of transistor 473. It can function as the other. Therefore, the semiconductor layer 242b is sandwiched between electrodes 244a and 244b. The resulting region 269 can function as a channel-forming region.

[0169] Furthermore, an oxide semiconductor layer 274 is provided on electrodes 244a and 244b, and an oxide An insulating layer 275 is provided on the semiconductor layer 274. Furthermore, the oxide semiconductor layer 274 and the insulating layer 275 are also provided. An opening is provided in the region overlapping with region 269 of layer 275, and along the side and bottom surfaces of the opening A semiconductor layer 242c is provided. Furthermore, within the opening, via the semiconductor layer 242c, Furthermore, an insulating layer 226 is provided along the side and bottom surfaces of the opening. via the semiconductor layer 242c and the insulating layer 226, and along the side and bottom surfaces of the opening Electrode 246 is provided.

[0170] Furthermore, in the cross-section in the channel width direction, the opening is formed by semiconductor layer 242a and semiconductor layer 24 It is provided to be larger than 2b. Therefore, in region 269, semiconductor layer 242a and The sides of semiconductor layer 242b are covered by semiconductor layer 242c. Semiconductor layers other than region 269 The sides of the body layer 242a and the semiconductor layer 242b are covered with an oxide semiconductor layer 274.

[0171] Furthermore, an insulating layer 276 is provided on the insulating layer 275, and an insulating layer 277 is provided on the insulating layer 276. Furthermore, electrodes 289a, 289b, and 289c are placed on the insulating layer 277. A is provided. The electrode 289a consists of insulating layer 277, insulating layer 276, insulating layer 275, and In the opening formed by removing a portion of the oxide semiconductor layer 274, the contact plug 28 It is electrically connected to electrode 244a via 8a. Also, electrode 289b is connected to insulating layer 2 77, formed by removing a portion of the insulating layer 276, the insulating layer 275, and the oxide semiconductor layer 274. In the opening, the electrode 244b is electrically connected via the contact plug 288b. Furthermore, electrode 289c is formed by removing a portion of the insulating layer 277 and insulating layer 276. In the opening, the electrode 246 is electrically connected via the contact plug 288c. Yes, they are.

[0172] Furthermore, as shown in Figure 18(B), transistor 473 has an electric current in the channel width direction. The pole 246 covers the semiconductor layer 242b. Also, the insulating layer 272 has a protrusion. Therefore, the sides of the semiconductor layer 242b can also be covered with electrodes 246.

[0173] The transistor 474 shown in Figures 19(A) and 19(B) consists of an insulating layer 273 and an insulating layer 2 The point where electrode 223, which functions as a back gate electrode, is provided between 72 is transistor 473. This differs from Figure 19(A). Figure 19(B) is a plan view of transistor 474. Cross-sections of the area indicated by the dashed line L1-L2 and the area indicated by the dashed line W1-W2 in 9(A). This is a diagram. Note that the electrode 223 may be placed between the substrate 271 and the insulating layer 273.

[0174] Both electrode 246 and electrode 223 can function as gate electrodes. The insulating layer 272 and the insulating layer 226 each function as gate insulating layers. It is possible.

[0175] By providing electrodes 246 and 223 with the semiconductor layer 242 in between, further, electrode 24 By setting electrode 6 and electrode 223 to the same potential, the carrier flow region in semiconductor layer 242 As the region becomes larger in the film thickness direction, the amount of carrier movement increases. As a result, As the on-current of the transistor 474 increases, the field-effect mobility also increases.

[0176] Furthermore, as shown in Figure 19(C), an insulating layer 281 is formed on the electrode 223, providing insulation. An insulating layer 282 may be formed on layer 281, and an insulating layer 272 may be formed on insulating layer 282. The insulating layer 281 and insulating layer 282 are formed using the same materials and methods as the insulating layer 272. It is possible.

[0177] Furthermore, the insulating layer 282 is made of hafnium oxide, aluminum oxide, tantalum oxide, and aluminum. By forming it with silicate or the like, the insulating layer 282 can function as a charge trapping layer. It is possible to change the threshold voltage of the transistor by injecting electrons into the insulating layer 282. This is possible. Electron injection into the insulating layer 282 can be achieved, for example, by utilizing the tunneling effect. Good. By applying a positive voltage to electrode 223, tunnel electrons are directed into the insulating layer 282. It is possible to enter.

[0178] <Regarding film formation methods> The conductive layers, insulating layers, and semiconductor layers of electrodes etc. shown in this specification may be manufactured by CVD, vapor deposition, etc. Alternatively, it can be formed using methods such as sputtering. Generally, CVD is a method that uses plasma Plasma-enhanced CVD (PECVD) that utilizes plasma These methods can be classified into categories such as thermal CVD (TCVD), which utilizes heat. Furthermore, depending on the source gas used, the process can be metal CVD (MCVD) or organic gold It can be classified into methods such as Metal Organic CVD (MOCVD).

[0179] Furthermore, generally speaking, vapor deposition methods include resistance heating deposition, electron beam deposition, and MBE (Molecular Beam Evaporation). Beam Epitaxy) method, PLD (Pulsed Laser Deposit) Ion method, IAD (Ion beam Assisted Deposition) method These methods can be classified into categories such as ALD (Atomic Layer Deposition).

[0180] Plasma CVD can produce high-quality films at relatively low temperatures. Also, MOCVD and vapor deposition methods... When using film deposition methods that do not use plasma during film formation, damage to the formed surface occurs. Furthermore, a film with fewer defects can be obtained.

[0181] Furthermore, generally speaking, sputtering methods include DC sputtering and magnetron sputtering. RF sputtering method, ion beam sputtering method, ECR (Electro n Cyclotron Resonance) Sputtering method, opposing target sputtering It can be classified into methods such as the Tarling method.

[0182] In the opposing target sputtering method, the plasma is confined between the targets, Plasma damage to the substrate can be reduced. Also, depending on the tilt of the target This allows for a shallower incidence angle of sputtering particles onto the substrate, thus improving step coverage. It is possible to do so.

[0183] Note that CVD and ALD are film deposition methods in which particles emitted from a target or other source are deposited. Unlike conventional methods, this film-forming method involves a reaction on the surface of the object being treated to form a film. Therefore, it is a film-forming method that is less affected by the shape of the workpiece and has good step-level coverage. In particular, the ALD method has excellent step coverage and excellent thickness uniformity, so the aspect ratio It is suitable for covering the surface of openings with a high to-ratio. However, the ALD method is relatively Because of its slow deposition rate, it is used in combination with other deposition methods that have a faster deposition rate, such as CVD. In some cases, this may be preferable.

[0184] The CVD and ALD methods allow control of the composition of the resulting film by adjusting the flow rate ratio of the source gas. This is possible. For example, in the CVD method and ALD method, the flow rate ratio of the raw material gas can be adjusted to any A film of a certain composition can be formed. Also, for example, in the CVD method and ALD method, the film is formed. By changing the flow rate ratio of the raw material gas, a film with a continuously changing composition is formed. This is possible. When forming a film while changing the flow rate ratio of the raw material gas, multiple deposition chambers can be used. Compared to the method used for film deposition, the time required for film deposition is reduced by eliminating the time spent on transport and pressure adjustment. This allows for increased productivity in transistors and semiconductor devices. There are cases where this is the case.

[0185] <Circuit board> There are no major restrictions on the material used as the substrate 271. Depending on the purpose, the presence or absence of light transmission and heat treatment may be considered. The decision should be made considering factors such as sufficient heat resistance to withstand the conditions. For example, barium borosilicate gas Glass substrates such as lath and aluminoborosilicate glass, ceramic substrates, quartz substrates, sapphire A substrate such as an earpiece can be used. In addition, the substrate 271 can be a semiconductor substrate or a flexible substrate. Flexible substrates, laminated films, base films, etc., may also be used.

[0186] For example, semiconductor substrates made of single-component materials such as silicon or germanium. Conductive substrate, or silicon carbide, silicon germanium, gallium arsenide, indium phosphide Examples include compound semiconductor substrates made from materials such as zinc oxide or gallium oxide. The semiconductor substrate may be a single-crystal semiconductor or a polycrystalline semiconductor.

[0187] Examples of materials for flexible substrates, laminated films, and base films include polyethylene. Lenterephthalate (PET), polyethylene naphthalate (PEN), polyethers Polyfluoroethylene (PES), polytetrafluoroethylene (PTFE), polypropylene, poly Esters, polyvinyl fluoride, polyvinyl chloride, polyolefins, polyamides (nylon) Polyimide, polycarbonate, aramid, epoxy resin, acrylic (including aramid) Resins and other materials can be used.

[0188] The flexible substrate used for substrate 271 is preferred if its coefficient of thermal expansion is low, as this suppresses deformation due to the environment. The flexible substrate used for substrate 271 has, for example, a coefficient of thermal expansion of 1 × 10 -3 / K or less, 5 ×10 -5 / K or less, or 1 × 10 -5 Materials with a temperature of / K or less should be used. In particular, A Lamid is suitable as a flexible substrate because it has a low coefficient of thermal expansion.

[0189] <Insulating layer> Insulating layer 272, insulating layer 226, insulating layer 225, insulating layer 228, and insulating layer 229 are made of nitrogen Aluminum oxide, aluminum nitride, aluminum nitride, aluminum oxide, acid Magnesium oxide, silicon nitride, silicon oxide, silicon nitride, silicon oxide nitride, Gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide Choose from neodymium oxide, hafnium oxide, tantalum oxide, aluminum silicate, etc. The materials are used in a single layer or in a laminated form. Also, oxide materials, nitride materials, oxidized nitrides Materials, or nitride oxide materials, may be used, or materials that are mixtures of multiple materials.

[0190] In this specification, nitride oxides refer to compounds in which the nitrogen content is greater than the oxygen content. Furthermore, oxidized nitrides are compounds in which the oxygen content is higher than the nitrogen content. The content can be measured, for example, by the Rutherford backscattering method (RBS). Measurements can be taken using methods such as kscattering (spectrometry). .

[0191] In particular, insulating layers 272 and 229 are formed using insulating materials that are resistant to the permeation of impurities. It is preferable to use boron, carbon, nitrogen, oxygen, fluorine, magnesium, aluminum. Titanium, silicon, phosphorus, chlorine, argon, gallium, germanium, yttrium, Insulating material containing zirconium, lanthanum, neodymium, hafnium, or tantalum, single layer Alternatively, it can be used in a laminated configuration. For example, as an insulating material that does not easily allow impurities to pass through, Aluminum, aluminum nitride, aluminum oxide nitride, aluminum oxide nitride, oxide Gallium, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, acid Examples include neodymium oxide, hafnium oxide, tantalum oxide, and silicon nitride. Furthermore, as the insulating layer 272 or insulating layer 229, a highly insulating indium tin zinc oxide (I You may also use materials such as n-Sn-Zn oxide.

[0192] By using an insulating material that is less permeable to impurities in the insulating layer 272, impurities from the substrate 271 side can be prevented. This suppresses the diffusion of pure substances and improves the reliability of the transistor. By using an insulating material that is difficult for substances to penetrate, the diffusion of impurities from the insulating layer 229 side is suppressed. This can improve the reliability of transistors.

[0193] Insulating layer 272, insulating layer 226, insulating layer 225, insulating layer 228, and insulating layer 229 Multiple insulating layers formed from these materials may be laminated and used. Insulating layer 272, insulating layer The method for forming 226, insulating layer 225, insulating layer 228, and insulating layer 229 is not particularly limited. Sputtering, CVD, MBE or PLD, ALD, spin coating, etc. Any of the various formation methods can be used.

[0194] For example, when depositing aluminum oxide using thermal CVD, the solvent and aluminum A raw material obtained by vaporizing a liquid containing a precursor compound (such as trimethylaluminum (TMA)). Two types of gases are used: a gas and H2O as an oxidizing agent. The chemical formula is Al(CH3)3. Other materials include tris(dimethylamide). ) Aluminum, Triisobutylaluminum, Aluminum Tris(2,2,6,6- Examples include tetramethyl-3,5-heptanedione.

[0195] Furthermore, when an oxide semiconductor is used as the semiconductor layer 242, the hydrogen concentration in the semiconductor layer 242 To prevent an increase, it is preferable to reduce the hydrogen concentration in the insulating layer. In particular, semiconductor layer 24 It is preferable to reduce the hydrogen concentration in the insulating layer that is in contact with 2. Specifically, the hydrogen in the insulating layer The concentration in SIMS is 2 × 10 20 atoms / cm 3 The following is preferably 5 × 10 19 atoms / cm 3 More preferably 1 × 10 19 atoms / cm 3 The following, More preferably 5 × 10 18 atoms / cm 3 The following applies. Also, in semiconductor layer 242 To prevent an increase in nitrogen concentration, it is preferable to reduce the nitrogen concentration in the insulating layer. In particular, semi It is preferable to reduce the nitrogen concentration in the insulating layer in contact with the conductive layer 242. Specifically, the insulating layer The nitrogen concentration in the layer was measured in SIMS at 5 × 10⁻⁶. 19 atoms / cm 3 Less than, preferably is 5 x 10 18 atoms / cm 3 More preferably 1 × 10 18 atoms / cm 3 More preferably 5 × 10 17 atoms / cm 3 The following applies:

[0196] Note that the concentration measured by SIMS analysis may include a variation of plus or minus 40%. There is.

[0197] Furthermore, when an oxide semiconductor is used as the semiconductor layer 242, the insulating layer releases oxygen when heated. It is preferable to form it using the resulting insulating layer. In particular, the insulating layer in contact with the semiconductor layer 242 A preferred insulating layer is one that releases oxygen upon heating. For example, a surface temperature of the insulating layer is 100°C. The heat treatment is carried out at a temperature of 700°C or higher, preferably 100°C or higher and 500°C or lower. Thermal Desorption Spectroscopy (TDS) In py), the amount of oxygen removed from the insulating layer, converted to the number of oxygen atoms, is 1.0 × 10⁻⁶. 18 a toms / cm 3 The above is preferable, 1.0 × 10 19 atoms / cm 3 The above is preferred. 1.0 × 10 20 atoms / cm 3 This is even more preferable. Furthermore, the oxygen released by heating is also called "excess oxygen."

[0198] Furthermore, an insulating layer containing excess oxygen can also be formed by adding oxygen to the insulating layer. It is possible. Processes that add oxygen include heat treatment in an oxygen atmosphere, ion implantation equipment, and ionization. This can be done using a doping device or a plasma processing device. As a gas, 16 O2 or 18 Oxygen gas such as O2, nitrous oxide gas, or ozone. Gases and the like can be used. In this specification, the process of adding oxygen is referred to as "oxygen doping." It is also called "processing".

[0199] Furthermore, the insulating layer is formed by sputtering in an oxygen-containing atmosphere. Oxygen can be introduced into the layer.

[0200] Furthermore, generally, capacitive elements have a configuration in which a dielectric is sandwiched between two opposing electrodes, and the dielectric The thinner the material (the shorter the distance between the two opposing electrodes), and the greater the dielectric constant of the dielectric material. The capacitance value increases as the dielectric material is thinned. And, due to the tunneling effect, etc., an unintended current flows between the two electrodes (hereinafter referred to as "Lee") Also called "current." This can easily increase the current, and the dielectric strength of capacitive elements can easily decrease. ru.

[0201] The area where the gate electrode, gate insulating layer, and semiconductor layer of a transistor overlap is a capacitive element. It functions (hereinafter also referred to as "gate capacitance"). Note that the gate insulating layer of the semiconductor layer A channel is formed in the region that overlaps with the gate electrode. That is, the gate electrode and the channel The formed region functions as two electrodes of the capacitive element. In addition, the gate insulating layer acts as an induction of the capacitive element. It functions as an electric body. A larger gate capacitance value is preferable, but increasing the capacitance value... Thinning the gate insulation layer to achieve this results in the aforementioned increase in leakage current and decrease in dielectric strength. This is a problem that is likely to occur.

[0202] Therefore, as a dielectric material, hafnium silicate (HfSi x O y (x>0, y>0), Nitrogen-added hafnium silicate (HfSi x O y N z (x>0, y>0, z>0 )), nitrogen-added hafnium aluminate (HfAl x O y N z (x>0, y>0 Using high-k materials such as z>0, hafnium oxide, or yttrium oxide This makes it possible to ensure sufficient capacitance of the capacitive element even when the dielectric material is thickened.

[0203] For example, if a high-k material with a high dielectric constant is used as the dielectric, even if the dielectric is made thicker... Therefore, since capacitance values ​​equivalent to those when silicon oxide is used as the dielectric can be achieved, the capacitive element This reduces the leakage current that occurs between the two electrodes being formed. A laminated structure of the material and other insulating materials may also be used.

[0204] Furthermore, the insulating layer 275 is an insulating layer having a flat surface. The insulating layer 275 is as described above. In addition to insulating materials, polyimide, acrylic resins, benzocyclobutene resins, poly Heat-resistant organic materials such as mids and epoxy resins can be used. In addition to mechanical materials, we also handle low-dielectric materials (low-k materials), siloxane resins, and PSG (Lingara). Materials such as BPSG (Limboron glass) can be used. Multiple insulating layers may be stacked.

[0205] Siloxane-based resins are formed using siloxane-based materials as starting materials. This corresponds to a resin containing Si bonds. Siloxane resins use organic groups (for example, aluminum) as substituents. You may also use chloroform groups (such as aryl groups) or fluoroform groups. Furthermore, the organic group may have a fluoroform group. It's okay to be there.

[0206] The method for forming the insulating layer 275 is not particularly limited and can be done by sputtering or SOG depending on the material. Spin coating, dipping, spray coating, droplet ejection (inkjet method, etc.), printing You can use methods such as screen printing or offset printing.

[0207] Furthermore, the sample surface may be subjected to CMP treatment. By performing CMP treatment, the sample surface This reduces surface irregularities and improves the coverage of subsequent insulating and conductive layers.

[0208] <Semiconductor layer> The semiconductor layer 242 can be a single-crystal semiconductor, a polycrystalline semiconductor, a microcrystalline semiconductor, or an amorphous semiconductor. These can be used. Examples of semiconductor materials include silicon and germanium. It can also be used. Furthermore, silicon germanium, silicon carbide, gallium arsenide, and acid Compound semiconductors such as hydrocarbon semiconductors and nitride semiconductors, as well as organic semiconductors, can be used. .

[0209] Furthermore, when an organic semiconductor is used as the semiconductor layer 242, a low-molecular-weight organic material with an aromatic ring is used. Other types of conductive polymers, such as π-electron conjugated polymers, can be used. For example, rubrene, tetracene Pentacene, perylenediimide, tetracyanoquinodimethane, polythiophene, polya Cetylene, poly(p-phenylene)vinylene, etc., can be used.

[0210] Furthermore, as mentioned above, the band gap of oxide semiconductors is 2eV or more, so semiconductor layer 2 Using an oxide semiconductor in 42 makes it possible to realize a transistor with extremely low off-current. Yes, it is possible. Also, OS transistors have high dielectric strength between the source and drain. Therefore, We can provide reliable transistors. Furthermore, we can provide reliable transistors for display devices and semiconductor devices. We can provide these.

[0211] This embodiment describes the case where an oxide semiconductor is used as the semiconductor layer 242. The oxide semiconductor used in semiconductor layer 242 is, for example, an oxide semiconductor containing indium (In). It is preferable to use a body. Oxide semiconductors, for example, if they contain indium, carrier transfer The mobility (electron mobility) increases. Furthermore, it is preferable for the oxide semiconductor to contain element M.

[0212] Element M is preferably aluminum, gallium, yttrium, or tin. Other elements to which element M can be applied include boron, silicon, titanium, iron, and nickel. Germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium Examples include M, tantalum, tungsten, and magnesium. However, as for element M, as mentioned above... In some cases, it is acceptable to combine multiple elements. Element M, for example, has a bonding energy with oxygen. It is an element with high ghee. Element M, for example, can significantly increase the energy gap of oxide semiconductors. It is an element that has the function of doing so. Furthermore, oxide semiconductors preferably contain zinc. Conductors can sometimes crystallize more easily when they contain zinc.

[0213] However, the oxide semiconductor used in semiconductor layer 242 is not limited to oxides containing indium. Oxide semiconductors include, for example, zinc-tin oxide, gallium-tin oxide, and gallium oxide. These include oxides that do not contain indium, oxides that contain zinc, oxides that contain gallium, and oxides that contain tin. It could be a semiconductor or something similar.

[0214] For example, as semiconductor layer 242, InGaZnO is produced by thermal CVD. X (X>0) Deposition of a film In some cases, trimethylindium (In(CH3)3) and trimethylgallium (Ga(C) H3)3) and dimethylzinc (Zn(CH3)2) are used. Also, combinations of these are used. Not limited to wasabi, triethylgallium (Ga(C2H5)) can be used instead of trimethylgallium. 3) can also be used, and diethylzinc (Zn(C2H5)2) can be used instead of dimethylzinc. It can also be used.

[0215] For example, as semiconductor layer 242, InGaZnO is produced by the ALD method. X (X>0) Deposition of a film In this case, an InO2 layer is formed by sequentially introducing In(CH3)3 gas and O3 gas repeatedly. Subsequently, Ga(CH3)3 gas and O3 gas are repeatedly introduced in sequence to form a GaO layer. Furthermore, Zn(CH3)2 gas and O3 gas are repeatedly introduced sequentially to form a ZnO layer. Note that the order of these layers is not limited to this example. Also, using these gases, InGaO Mixed compound layers such as two layers, two InZnO layers, GaInO layers, ZnInO layers, and GaZnO layers. Alternatively, you can form H by bubbling water with an inert gas such as Ar instead of O3 gas. While 2O gas may be used, it is preferable to use O3 gas that does not contain H. Also, In( Instead of CH3)3 gas, use In(C2H5)3 gas or tris(acetylacetonato)in. Dium may also be used. Note that tris(acetylacetonato)indium is In(ac It is also called ac)3. In addition, Ga(C2H5)3 gas can be used instead of Ga(CH3)3 gas. You may also use tris(acetylacetonato)gallium. Gallium is also called Ga(acac)3. It is also known as Zn(CH3)2 gas and ammonium acetate. Lead may be used. These gas types are not the only ones that may be used.

[0216] When depositing oxide semiconductor films using the sputtering method, in order to reduce the number of particles, It is preferable to use a target containing M. Furthermore, oxide targets with a high atomic ratio of element M are also preferable. When using a target, the conductivity of the target may decrease. (Target containing indium) When using this method, the conductivity of the target can be increased, and DC discharge and AC discharge can be easily performed. This makes it easier to handle large-area substrates. Therefore, it increases the productivity of semiconductor devices. It is possible.

[0217] Furthermore, as mentioned above, when depositing oxide semiconductors using the sputtering method, the target material For example, the ratio of the number of offspring can be In:M:Zn as 3:1:1, 3:1:2, 3:1:4, 1:1:0. If you use .5, 1:1:1, 1:1:2, 1:4:4, 5:1:7, 4:2:4.1, etc. good.

[0218] Furthermore, when oxide semiconductors are deposited using the sputtering method, the atomic ratio deviates from that of the target. In some cases, oxide semiconductors with atomic ratios can be deposited. In particular, zinc is a target with atomic ratios. In some cases, the atomic ratio of the deposited film may be smaller than that. Specifically, the target contains In cases where the atomic ratio of zinc is between 40 atomic% and approximately 90 atomic% be.

[0219] Furthermore, in order to impart stable electrical characteristics to the OS transistor, the oxide semiconductor layer is necessary. By reducing the amount of pure material and oxygen deficiencies, the semiconductor layer 242 is made highly pure and intrinsic, and substantially It is preferable to use an oxide semiconductor layer that can be considered to be of high purity and intrinsic. Also, at least a semiconductor The channel-forming region in layer 242 is an oxide that can be considered to be of high purity intrinsic or substantially high purity intrinsic. It is preferable to use a semiconductor layer.

[0220] Furthermore, when an oxide semiconductor is used for semiconductor layer 242, CAAC-OS(C Axis Aligned Crystalline Oxide Semiconductor) It is preferable to use CAAC-OS. CAAC-OS is an oxide having multiple c-axis oriented crystalline parts. It is a type of semiconductor.

[0221] Furthermore, the oxide semiconductor layer used in semiconductor layer 242 has a region that is not CAAC that is the oxide semiconductor layer. It is preferable that it accounts for less than 20% of the total body layer.

[0222] CAAC-OS has dielectric anisotropy. Specifically, CAAC-OS has dielectric anisotropy in the a-axis direction and The dielectric constant in the c-axis direction is greater than the dielectric constant in the b-axis direction. A transistor using CAAC-OS with the gate electrode positioned in the c-axis direction is c-axis direction Because of its high dielectric constant, the electric field generated from the gate electrode easily reaches the entire CAAC-OS. This allows for a reduction in the subthreshold swing value (S value). Also, semiconductors Transistors using CAAC-OS in the layer are less susceptible to an increase in S value due to miniaturization.

[0223] Furthermore, because CAAC-OS has low dielectric constants in the a-axis and b-axis directions, the source and dray The effects of the electric field generated between channels are mitigated. Therefore, channel length modulation effects and short channel effects are reduced. This reduces the likelihood of such problems occurring, thereby improving the reliability of the transistor.

[0224] Here, the channel length modulation effect refers to the effect that occurs when the drain voltage is higher than the threshold voltage. This refers to the phenomenon where the depletion layer expands from the input side, shortening the effective channel length. The channel length reduction effect refers to the deterioration of electrical characteristics, such as a decrease in threshold voltage, that occurs when the channel length is shortened. This refers to the phenomenon in which degradation occurs. The smaller the transistor, the greater the degradation of its electrical characteristics due to these phenomena. It is likely to occur.

[0225] After forming the oxide semiconductor layer, oxygen doping may be performed. To further reduce impurities such as water or hydrogen and to increase the purity of the oxide semiconductor layer It is preferable to perform a heat treatment.

[0226] For example, under a reduced pressure atmosphere, under an inert atmosphere such as nitrogen or a noble gas, under an oxidizing atmosphere, or in an ultra-dry atmosphere. Dry air (measured using a CRDS (Cavity Ring-Down Laser Spectroscopy) type dew point meter) In that case, the moisture content is 20 ppm or less (dew point equivalent to -55°C), preferably 1 ppm or less. Preferably, the oxide semiconductor layer is subjected to heat treatment in an atmosphere of 10 ppb or less (air). An oxidizing atmosphere is defined as an atmosphere containing oxidizing gases such as oxygen, ozone, or oxygen nitride at a concentration of 10 ppm or more. This refers to the atmosphere that is present. Furthermore, an inert atmosphere is one in which the aforementioned oxidizing gas is present at a concentration of less than 10 ppm. This also refers to an atmosphere filled with nitrogen or other noble gases.

[0227] Furthermore, by performing the heat treatment, impurities are released, and at the same time, oxygen contained in the insulating layer 226 is removed. By diffusing it into the oxide semiconductor layer, the oxygen vacancies contained in the oxide semiconductor layer can be reduced. Yes, it is possible. Furthermore, after heat treatment in an inert atmosphere, an oxidizing gas is used to replenish the desorbed oxygen. Heat treatment may be carried out in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of the substance. Oh, the heat treatment can be performed at any time after the oxide semiconductor layer has been formed.

[0228] There are no special limitations on the heating equipment used for the heat treatment, and heat conduction from heat sources such as resistance heating elements is also possible. Alternatively, it may be a device that heats the object to be processed by thermal radiation. For example, an electric furnace or an LR TA (Lamp Rapid Thermal Anneal) equipment, GRTA (Gas Rapid Thermal Annealing (RTA) devices, etc. A mal Anneal) device can be used. The LRTA device uses a halogen lamp, Metal halide lamps, xenon arc lamps, carbon arc lamps, high-pressure sodium The light (electromagnetic waves) emitted from lamps such as lamps and high-pressure mercury lamps can cause the treated material to be affected by radiation. It is a heating device. A GRTA device is a device that performs heat treatment using high-temperature gas.

[0229] The heat treatment should be carried out at a temperature of 250°C to 650°C, preferably 300°C to 500°C. Good. The processing time should be within 24 hours. Heating for more than 24 hours will lead to a decrease in productivity. Therefore, it is undesirable.

[0230] <Electrode> Electrode 246, Electrode 223, Electrode 244a, Electrode 244b, Electrode 287, Electrode 297, Electrode 289a, electrode 289b, electrode 292a, electrode 292b are conductive materials used to form electrode 289a, electrode 289b, electrode 292a, and electrode 292b. For example, aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum Den, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium Materials containing one or more metallic elements selected from conium, beryllium, etc. can be used. Furthermore, polycrystalline silicon containing impurity elements such as phosphorus has high electrical conductivity. High semiconductor properties, such as nickel silicide, may be used. Formed from these materials. Multiple conductive layers may be stacked and used.

[0231] Also, electrodes 246, 223, 244a, 244b, 287, and 297 conductive material for forming electrodes 289a, 289b, 292a, and 292b The material contains indium tin oxide (ITO), tungsten oxide Indium oxide containing tungsten, indium zinc oxide containing tungsten oxide, and tungsten oxide. Indium oxide containing tungsten, indium tin oxide containing titanium oxide, indium zinc oxide Acids such as zinc oxide, indium gallium zinc oxide, and silicon-added indium tin oxide. Apply conductive materials containing nitrogen, such as titanium nitride and tantalum nitride. It is also possible to combine the aforementioned metal element-containing material with an oxygen-containing conductive material. It can also be made into a laminated structure. In addition, the material containing the aforementioned metal element and the nitrogen-containing conductive material can be used. It is also possible to create a laminated structure by combining electrolytic materials. The laminated structure combines a conductive material containing oxygen and a conductive material containing nitrogen. It is also possible. The method of forming the conductive material is not particularly limited and includes vapor deposition, CVD, sputtering, etc. Various forming methods, such as the molding method, can be used.

[0232] <Contact plug> Contact plug 288a, contact plug 288b, contact plug 288c, For example, the contact plug 298a and contact plug 298b are made of tungsten. Highly embedding conductive materials such as tene and polysilicon can be used. The sides and bottom of the material are protected by a barrier layer consisting of a titanium layer, a titanium nitride layer, or a laminate thereof. It may be covered with a (diffusion prevention layer). In this case, the contact plug is also considered to include the barrier layer. There is a match.

[0233] According to one aspect of the present invention, a transistor with good electrical characteristics can be realized. According to one aspect of the present invention, a semiconductor device with a high degree of integration can be realized.

[0234] This embodiment can be implemented in appropriate combination with the configurations described in other embodiments. That is the case.

[0235] (Embodiment 3) In this embodiment, an example is given in which the semiconductor device described in the above embodiment is applied to an electronic component, Examples of electronic devices equipped with the said electronic components will be explained using Figures 21 and 22. Electronic components are also called semiconductor packages or IC packages. Depending on the direction of output and the shape of the terminals, multiple standards and names exist. In this section, an example of an electronic component will be described.

[0236] In the assembly process (downstream process), the electronic component is the semiconductor device shown in the above embodiment and The semiconductor device is completed by assembling components other than semiconductor devices.

[0237] The subsequent process will be explained using the flowchart shown in Figure 21(A). After the element substrate having the semiconductor device shown in the above embodiment is completed, the back surface of the element substrate ( The "backside grinding process" is performed to grind the surface (where semiconductor devices, etc., are not formed) (step S1). By thinning the element substrate through grinding, warping of the element substrate is reduced, and electronic components This allows for miniaturization.

[0238] Next, a "dicing process" is performed to separate the element substrate into multiple chips (step S2). Then, the separated chips are individually picked up and bonded onto the lead frame in a process called "Die Bonding". The "die bonding process" is performed (step S3). The tip and lead in the die bonding process. The connection to the frame can be made using resin bonding, tape bonding, or other methods appropriate to the product. Select the method. Note that instead of a lead frame, the chip is bonded to the interposer substrate. You may do so.

[0239] Next, the leads of the lead frame and the electrodes on the chip are electrically connected using a thin metal wire. A "wire bonding process" is performed to connect the wires (step S4). For the thin metal wires, Silver or gold wire can be used. Also, wire bonding is a type of ball bonding. Alternatively, wedge bonding can be used.

[0240] The wire-bonded chips undergo a "sealing process" where they are sealed with epoxy resin or the like. The "sealing process" is performed (step S5). The sealing process seals the inside of the electronic component with resin. It is filled with a mechanical material that encloses the circuitry within the chip and the wires connecting the chip to the leads. It can be protected from external forces and reduces the degradation of its properties (reduction in reliability) due to moisture and dust. It is possible.

[0241] Next, the "lead plating process" is performed to plate the leads of the lead frame (ste (S6). Plating prevents lead rust, and when later mounted on a printed circuit board... This allows for more reliable soldering. Next, the leads are cut and shaped. The "shaping process" is performed (step S7).

[0242] Next, the "marking process" is performed, in which printing (marking) is applied to the surface of the package. (Step S8). Then, the "inspection process" to check the quality of the external shape and whether there are any malfunctions. After step S9), the electronic component is completed.

[0243] The electronic components described above include the transistor described in the above embodiment. This allows for reduced malfunctions in high-temperature environments and lower manufacturing costs. This enables the realization of electronic components having a semiconductor device. This electronic component can be used in high-temperature environments. This includes a semiconductor device in which malfunctions in the following areas are reduced and manufacturing costs are suppressed, These are electronic components that have been miniaturized and have relaxed restrictions on their operating environment.

[0244] Furthermore, a schematic perspective view of the completed electronic component is shown in Figure 21(B). In Figure 21(B), the electronic part As an example of a product, a schematic diagram of a QFP (Quad Flat Package) is shown. The electronic component 700 shown in Figure 21(B) includes a lead 705 and a semiconductor device 703. The semiconductor device 703 is the semiconductor device shown in the above embodiment. It is possible.

[0245] The electronic component 700 shown in Figure 21(B) is mounted on a printed circuit board 702, for example. Multiple electronic components 700 are combined, and each is electrically connected on the printed circuit board 702. The connection completes the circuit board (mounted board 704) with the electronic components mounted on it. The circuit board 704 is used in electronic devices and the like.

[0246] Next, referring to Figure 22, the following are provided for vehicles (bicycles, etc.) that are powered by a fixed power source. Examples of applications include applying the aforementioned electronic components to drive circuits that drive inverters, motors, etc. I will explain about this.

[0247] Figure 22(A) shows an electric bicycle 1010 as an application example. This system obtains power by passing an electric current through the motor 1011. Also, electric bicycles... 1010 is a power storage device 1012 for supplying current to the motor 1011, and It has a drive circuit 1013 for driving the motor. Note that in Figure 22(A), the pedal is Although illustrated, it is not necessary.

[0248] The drive circuit 1013 is provided with an electronic component having the semiconductor device shown in the previous embodiment. A mounting board is installed. Therefore, electric bicycles equipped with miniaturized electronic components This can be achieved. Furthermore, it will be possible to create electric bicycles with low power consumption and long range. This makes it possible to create highly reliable electric bicycles.

[0249] Figure 22(B) shows another application example, the electric vehicle 1020. 20 obtains power by passing electric current through motor 1021. The electric locomotive 1020 has a power storage device 1022 for supplying current to the motor 1021, and It has a drive circuit 1023 for driving a motor.

[0250] The drive circuit 1023 is provided with an electronic component having the semiconductor device shown in the previous embodiment. A mounting board is installed. Therefore, electric vehicles equipped with miniaturized electronic components This can be achieved. Furthermore, it will enable the creation of electric vehicles with low power consumption and long driving range. This makes it possible to create highly reliable electric vehicles.

[0251] Furthermore, the electronic component having the semiconductor device shown in the above embodiment is not limited to electric vehicles (EVs). It is not used in hybrid electric vehicles (HEVs) or plug-in hybrid electric vehicles (PHEVs). It is also possible.

[0252] As described above, the electronic device shown in this embodiment has a semiconductor device according to the previous embodiment. A mounting board with electronic components is installed. Therefore, miniaturized electronics It is possible to realize electronic devices equipped with components. Furthermore, it is possible to realize electronic devices with low power consumption. This is possible. Furthermore, it is possible to create highly reliable electronic devices.

[0253] This embodiment can be implemented in appropriate combination with the configurations described in other embodiments. That is the case.

[0254] (Embodiment 4) A semiconductor device according to one aspect of the present invention can be used in the control circuits of various electronic devices. Figure 23 shows a specific example of an electronic device using a semiconductor device according to one aspect of the present invention.

[0255] Electronic devices using a semiconductor device according to one aspect of the present invention include display devices such as televisions and monitors. Lighting equipment, desktop or notebook personal computers, word processors The data is stored on recording media such as DVDs (Digital Versatile Discs). Image playback devices that play back still images or videos, portable CD players, radios, tapes Recorder, headphone stereo, stereo, desk clock, wall clock, cordless phone handset transceivers, mobile phones, car phones, portable game consoles, tablet devices, pachinko Large game consoles such as machines, calculators, personal digital assistants, electronic organizers, e-readers, electronic translators, sound High frequency input devices such as voice input devices, video cameras, digital still cameras, electric shavers, and microwave ovens. Wave heating device, electric rice cooker, electric washing machine, electric vacuum cleaner, water heater, electric fan, hair dryer, air Air conditioning equipment such as conditioners, humidifiers, and dehumidifiers, dishwashers, dish dryers, and clothes dryers. Dishes, futon dryers, electric refrigerators, electric freezers, electric refrigerator-freezers, DNA storage freezers, pockets Examples include electric lights, tools such as chainsaws, smoke detectors, and medical equipment such as dialysis machines. Furthermore, guide lights, traffic lights, conveyor belts, elevators, escalators, and industrial robots. Industrial equipment such as power storage systems, energy leveling systems, and energy storage devices for smart grids. These are some examples.

[0256] Furthermore, mobile devices propelled by electric motors using electricity from energy storage devices also fall under the category of electronic equipment. This shall be included in the above-mentioned mobile devices, for example, electric vehicles (EVs), internal combustion engines and electric vehicles. Hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) that combine the two motives, Tracked vehicles that replace these tire wheels with tracks, and motorized vehicles including electric assist bicycles. Bicycles, motorcycles, electric wheelchairs, golf carts, small or large vessels, submarines, helicopters Examples include aircraft, rockets, satellites, space probes and planetary probes, and spacecraft. .

[0257] Figure 23 shows an example of an electronic device. In Figure 23, the display device 8000 is an embodiment of the present invention. This is an example of an electronic device using semiconductor device 8004 related to the above. Specifically, display device 800 0 corresponds to a display device for receiving TV broadcasts, and consists of a housing 8001, a display unit 8002, and a speaker unit. It includes 8003, semiconductor device 8004, energy storage device 8005, etc. According to one aspect of the present invention The semiconductor device 8004 is located inside the housing 8001. This involves controlling the operation of the cooling fan inside the display device 8000 and adjusting the brightness of the light emission. It can do that. Also, the display device 8000 can receive power from the commercial power supply. Alternatively, the power stored in the energy storage device 8005 can be used.

[0258] The display unit 8002 has light-emitting elements such as liquid crystal display devices and organic EL elements in each pixel. Equipment, electrophoresis display device, DMD (Digital Micromirror Display) ce), PDP (Plasma Display Panel), FED (Field Display devices such as Emission Displays can be used.

[0259] In addition to being used for receiving TV broadcasts, display devices are also used for personal computers, advertising displays, and more. This includes all information display devices.

[0260] In Figure 23, the fixed lighting device 8100 is a semiconductor device 8 according to one aspect of the present invention. This is an example of an electronic device using 103. Specifically, the lighting device 8100 has a housing 8101, It includes a light source 8102, a semiconductor device 8103, an energy storage device 8105, etc. Figure 23 shows the semiconductor The main unit 8103 is located inside the ceiling 8104 on which the housing 8101 and light source 8102 are installed. The example shows the case where it is located in the housing 8101, but the semiconductor device 8103 is located inside the housing 8101. It may be provided. The semiconductor device 8103 controls the luminescence brightness of the light source 8102. It is possible. Furthermore, the lighting device 8100 can also receive power from the commercial power supply. Yes, it's possible, and it's also possible to use the electricity stored in the energy storage device.

[0261] Note that Figure 23 illustrates a fixed lighting device 8100 installed on the ceiling 8104. However, the semiconductor device according to one aspect of the present invention has, in addition to the ceiling 8104, for example, a side wall 8405, a floor It can also be used in fixed lighting fixtures installed in windows such as 8406 and 8407, It can also be used in tabletop lighting devices and the like.

[0262] Furthermore, the light source 8102 can be an artificial light source that uses electricity to artificially produce light. Specifically, this includes incandescent light bulbs, discharge lamps such as fluorescent lamps, and light-emitting elements such as LEDs and organic EL elements. The element is an example of the artificial light source mentioned above.

[0263] In Figure 23, the air conditioner having an indoor unit 8200 and an outdoor unit 8204 is, This is an example of an electronic device using a semiconductor device 8203 according to one aspect of the present invention. Specifically, the room The internal unit 8200 consists of a housing 8201, an air outlet 8202, a semiconductor device 8203, and a power storage device 820. It has 5, etc. In Figure 23, the semiconductor device 8203 is installed in the indoor unit 8200. Although this is an example, the semiconductor device 8203 may also be installed on the outdoor unit 8204. Alternatively, the semiconductor device 8203 is provided on both the indoor unit 8200 and the outdoor unit 8204. It is also acceptable. The semiconductor device 8203 is used in the compressor of an air conditioner. It can control the operation of the motor. Also, the air conditioner is powered by commercial power. It can also receive power from the power supply, or it can use the power stored in the energy storage device 8205. It's also possible.

[0264] Note that Figure 23 shows a separate-type air conditioner consisting of an indoor unit and an outdoor unit. As an example, an integrated air conditioner has both the indoor and outdoor unit functions in a single housing. A semiconductor device according to one aspect of the present invention can also be used as the conditioner.

[0265] In Figure 23, the electric refrigerator 8300 is a semiconductor device 8304 according to one aspect of the present invention. This is an example of an electronic device using [a specific component]. Specifically, the electric refrigerator 8300 has a casing 8301, Refrigerator door 8302, freezer door 8303, semiconductor device 8304, energy storage device 8305, etc. It has. In Figure 23, the semiconductor device 8304 provided inside the housing 8301 This allows for the control of the motor used in the compressor of the 8300 electric refrigerator / freezer. Yes, it is possible. Furthermore, the 8300 electric refrigerator / freezer can also receive power from the commercial power supply. Furthermore, the power stored in the energy storage device 8305 can also be used.

[0266] Of the electronic devices mentioned above, high-frequency heating devices such as microwave ovens and electric rice cookers are included. Sub-devices require high power for short periods of time. They also need to control high power stably over a certain period. It is necessary. By using a semiconductor device according to one aspect of the present invention, power control can be performed stably. This makes it possible to create highly reliable electronic devices.

[0267] This embodiment can be implemented in appropriate combination with other embodiments. [Explanation of symbols]

[0268] 100 Semiconductor Devices 101 terminals 102 terminals 103 terminals 104 terminals 105 terminals 106 terminals 110 Semiconductor Equipment 111 transistors 112 transistors 113 Transistors 114 transistors 117 Capacitive elements 120 Semiconductor Equipment 121 Wiring 122 Wiring 123 Wiring 124 Wiring 125 Wiring 130 Semiconductor Equipment 131 nodes 132 nodes 133 nodes 151 period 152 period 214 layers 223 Electrode 225 Insulating layer 226 Insulating layer 227 Insulating layer 228 Insulating layer 229 Insulating layer 242 Semiconductor layer 243 Electrode 246 Electrode 255 Impurities 269 ​​areas 271 circuit boards 272 Insulating layer 273 Insulating layer 274 Oxide semiconductor layer 275 Insulating layer 276 Insulating layer 277 Insulating layer 281 Insulating layer 282 Insulating layer 287 Electrode 297 Electrode 382 Ec 386 Ec 387 Ec 390 Trap Level 410 transistors 411 transistors 420 transistors 421 Transistors 422 transistors 425 transistors 426 transistors 430 transistors 431 transistors 440 transistors 441 transistors 442 transistors 443 transistors 444 transistors 445 transistors 446 transistors 447 transistors 448 transistors 450 transistors 451 transistors 452 transistors 473 transistors 474 transistors 700 Electronic Components 702 Printed circuit board 703 Semiconductor Equipment 704 Mounted circuit board 705 Lead 1010 Electric Bicycle 1011 Motor 1012 Energy storage device 1013 Drive Circuit 1020 Electric Vehicles 1021 Motor 1022 Energy storage device 1023 Drive Circuit 8000 display device 8001 enclosure 8002 Display section 8003 Speaker section 8004 Semiconductor Equipment 8005 Energy Storage Device 8100 Lighting device 8101 enclosure 8102 Light source 8103 Semiconductor Equipment 8104 Ceiling 8105 Energy Storage Device 8200 indoor unit 8201 enclosure 8202 Air outlet 8203 Semiconductor Equipment 8204 Outdoor unit 8205 Energy Storage Device 8300 Electric Refrigerator / Freezer 8301 enclosure 8302 Refrigerator door 8303 Freezer door 8304 Semiconductor Equipment 8305 Energy Storage Device 8405 Side wall 8406 floors 8407 Window 100a Semiconductor 100b Semiconductor equipment 100c Semiconductor device 110a Semiconductor 110b Semiconductor equipment 110c Semiconductor device 120a Semiconductor 130a Semiconductor 242a Semiconductor layer 242b Semiconductor layer 242c semiconductor layer 242i semiconductor layer 242t semiconductor layer 242u semiconductor layer 244a electrode 244b electrode 247a aperture 247b aperture 247c aperture 247d aperture 288a Contact Plug 288b Contact Plug 288c Contact Plug 289a electrode 289b Electrode 289c electrode 292a electrode 292b Electrode 298a Contact Plug 298b Contact Plug 383a Ec 383b Ec 383c Ec

Claims

[Claim 1] It has first to fourth transistors and capacitive elements, Each of the first to fourth transistors has a first gate and a second gate, The first gate of the first transistor is electrically connected to the first wiring, The second gate of the first transistor is electrically connected to the first wiring, Either the source or the drain of the first transistor is electrically connected to the first wiring, The source or drain of the first transistor is electrically connected to the source or drain of the second transistor. The source or drain of the second transistor, the other of which is electrically connected to the second wiring, The first gate of the second transistor is electrically connected to the second gate of the second transistor. Either the source or drain of the third transistor is electrically connected to the first wiring. The first gate of the third transistor is electrically connected to the other of the source or drain of the first transistor. The second gate of the third transistor is electrically connected to the other of the source or drain of the third transistor. One of the source or drain of the fourth transistor is electrically connected to the other of the source or drain of the third transistor. The source or drain of the fourth transistor, the other of which is electrically connected to the second wiring, The first gate of the fourth transistor is electrically connected to the second gate of the fourth transistor. The first gate of the fourth transistor is electrically connected to the first gate of the second transistor. One electrode of the capacitive element is electrically connected to the first gate of the third transistor. The other electrode of the capacitive element is electrically connected to the other source or drain of the third transistor in a semiconductor device.

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