Semiconductor device, operational amplifier, and display device

Abstract

To provide a semiconductor device capable of generating current with smaller variation.SOLUTION: A semiconductor device includes: a first transistor including a first gate electrode; and a second transistor including a second gate electrode electrically connected to the first gate electrode, and having a source electrode electrically connected to the second gate electrode electrically connected to the first gate electrode and to a drain electrode of the first transistor. The first transistor has a first channel width and a first gate length. The second transistor has a second channel width and a second gate length. A value obtained by dividing the second channel width by the second gate length is more than or equal to a value obtained by dividing the first channel width by the first gate length.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a semiconductor device, an operational amplifier, and a display device, and more specifically, to a semiconductor device, an operational amplifier including the semiconductor device, and a display device including the operational amplifier. [Background technology]

[0002] Various display devices are implemented in televisions, smartphones, and the like and are in widespread use. A display device includes, for example, a plurality of pixels. A display device may also include an operational amplifier that amplifies a signal that drives the plurality of pixels, or an operational amplifier that generates a power supply voltage used within the display device. By including an operational amplifier, the display device can operate using a signal and a power supply voltage with, for example, little voltage fluctuation or frequency fluctuation.

[0003] For example, Patent Document 1 discloses a liquid crystal display device equipped with an amplifier circuit including an operational amplifier. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-083804 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order for an operational amplifier to generate a signal and a power supply voltage with little voltage fluctuation or frequency fluctuation, for example, a constant current source included in the operational amplifier needs to generate a current with little fluctuation.

[0006] In view of such problems, an object of one embodiment of the present invention is to provide a semiconductor device capable of generating a current with little fluctuation, an operational amplifier including the semiconductor device, and a display device including the operational amplifier. [Means for solving the problem]

[0007] A semiconductor device according to one embodiment of the present invention includes a first transistor including a first gate electrode, and a second transistor having a second gate electrode electrically connected to the first gate electrode and a source electrode electrically connected to a drain electrode of the first transistor, wherein the first transistor has a first channel width and a first gate length, the second transistor has a second channel width and a second gate length, and a value obtained by dividing the second channel width by the second gate length is greater than or equal to a value obtained by dividing the first channel width by the first gate length.

[0008] One embodiment of the present invention is an operational amplifier including a plurality of the semiconductor devices.

[0009] One embodiment of the present invention is a display device including the operational amplifier and a plurality of pixels electrically connected to the operational amplifier. [Brief description of the drawings]

[0010] [Figure 1] 1 is a circuit diagram showing a configuration of a constant current source including a semiconductor device according to a first embodiment of the present invention. [Diagram 2] 3A to 3C are diagrams illustrating examples of voltages applied to terminals of the constant current source according to the first embodiment of the present invention. [Diagram 3] FIG. 4 is a diagram showing an example of electrical characteristics of the constant current source according to the first embodiment of the present invention. [Figure 4] 4 is a graph showing actual measurement results of electrical characteristics of the constant current source according to the first embodiment of the present invention. [Diagram 5] 1 is a diagram showing an example of a layout of a semiconductor device according to an embodiment of the present invention; [Figure 6] 6 is a cross-sectional view showing a cross-sectional structure taken along A1-A2 in FIG. 5. [Figure 7] 1 is a diagram showing an example of a layout of a semiconductor device according to an embodiment of the present invention; [Figure 8]1 is a diagram showing an example of a layout of a semiconductor device according to an embodiment of the present invention; [Figure 9] FIG. 5 is a circuit diagram showing a configuration of an operational amplifier according to a second embodiment of the present invention. [Figure 10] FIG. 11 is a plan view showing a configuration of a display device according to a third embodiment of the present invention. [Figure 11] FIG. 11 is a plan view showing a configuration of a display device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different aspects, and should not be interpreted as being limited to the description of the embodiments exemplified below. In the drawings, the width, thickness, shape, etc. of each part may be shown diagrammatically compared to the actual aspect in order to make the explanation clearer, but it is merely an example and does not limit the interpretation of the present invention. In this specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals (or reference numerals with a, b, etc. added after the numerals) and detailed explanations may be omitted as appropriate. Furthermore, the letters "first" and "second" added to each element are convenient labels used to distinguish each element, and have no further meaning unless otherwise specified.

[0012] In this specification, when a component or region is described as being "on (or under)" another component or region, unless otherwise specified, this includes not only the case where it is directly on (or directly under) the other component or region, but also the case where it is above (or below) the other component or region, i.e., the case where another component is included between the component or region and above (or below) the other component or region.

[0013] In the present specification, the D1 direction intersects with the D2 direction, and the D3 direction intersects with the D1 and D2 directions (D1D2 plane). The D1 direction is called the first direction, the D2 direction is called the second direction, and the D3 direction is called the third direction. For example, the D1, D2, and D3 directions correspond to the X direction (x direction), the Y direction (y direction), and the Z direction (z direction).

[0014] In the present specification, when the terms "same" and "match" are used, the terms "same" and "match" may include a margin of error within the range of design.

[0015] First Embodiment 1 to 8, a constant current source 11 including a semiconductor device 10 will be described. The constant current source 11 is, for example, a power supply circuit that keeps the output current constant regardless of the magnitude of the connected load.

[0016] <1-1. Configuration of semiconductor device 10> 1 and 2, the configurations of a semiconductor device 10 and a constant current source 11 including the semiconductor device 10 will be described. Fig. 1 is a circuit diagram showing the configuration of a constant current source 11 including the semiconductor device 10. Fig. 2 is a diagram for explaining an example of voltages applied to each terminal of the constant current source 11.

[0017] As shown in FIG. 1, the constant current source 11 includes a semiconductor device 10. The semiconductor device 10 includes a first transistor 100 including a gate electrode 102, a source electrode 104, and a drain electrode 106, and a second transistor 110 including a gate electrode 112 electrically connected to the gate electrode 102, a source electrode 114 electrically connected to the drain electrode 106, and a drain electrode 116. The drain electrode 106 and the source electrode 114 are connected to each other via an intermediate electrode MID. The intermediate electrode MID may be referred to as an intermediate node. In this specification and the drawings, the function of each electrode as a source and the function as a drain may be interchanged depending on the voltage supplied (applied) to the source electrode and the drain electrode of the transistor.

[0018] The gate electrode 102 and the gate electrode 112 are electrically connected to an input signal line 12. The source electrode 104 is electrically connected to a first voltage supply wiring 14. The drain electrode 116 is electrically connected to an output signal line 16.

[0019] The names of the terminals do not limit the input and output of the constant current source 11. The input and output to the constant current source 11 may be switched depending on the voltage of the output signal OUT1 and the voltage of the input signal IN1.

[0020] An input signal IN1 is supplied to an input signal line 12, a common voltage VL is supplied to a first voltage supply wiring 14, and an output signal OUT1 is output to an output signal line 16. The common voltage VL may be, for example, a ground voltage, 0 V, VSS, a ground voltage, or a voltage that serves as a reference in a device that uses the common voltage VL.

[0021] 2, the semiconductor device 10 and the constant current source 11 including the semiconductor device 10 may be regarded as including one transistor including two gate electrodes (so-called double gate). In the constant current source 11, the output signal line 16 may be regarded as a drain terminal D, the input signal line 12 as a gate terminal G, and the first voltage supply wiring 14 as a source terminal S.

[0022] For example, a voltage Vg is applied to the gate terminal G, the gate electrode 102 and the gate electrode 112, a voltage Vs is applied to the source terminal S and the source electrode 104, a voltage Vd is applied to the drain terminal D and the drain electrode 116, and a voltage Vm is applied to the intermediate electrode MID. The voltage Vs is, for example, 0 V.

[0023] The gate-source voltage Vgs1 applied between the gate electrode 102 and the source electrode 104 of the first transistor 100 is Vg-Vs=Vg-0=Vg. The drain-source voltage Vds1 applied between the drain electrode 106 and the source electrode 104 of the first transistor 100 is Vm-Voltage Vs=Voltage Vm-0=Vm.

[0024] A gate-source voltage Vgs2 applied between the gate electrode 112 and the source electrode 114 of the second transistor 110 is the voltage Vg-voltage Vm. A drain-source voltage Vds2 applied between the drain electrode 116 and the source electrode 114 of the second transistor 110 is the voltage Vd-voltage Vm.

[0025] <1-2. Comparison of electrical characteristics> The electrical characteristics of the constant current source 11 will be described with reference to Figures 3 and 4. Figure 3 is a diagram showing an example of the electrical characteristics of the constant current source 11 including the semiconductor device 10. Figure 4 is a graph showing the actual measurement results of the semiconductor device 10. Note that in Figures 3 and 4, in addition to the electrical characteristics of the constant current source 11, the electrical characteristics of a single-gate constant current source of Comparative Example 1 and the electrical characteristics of a double-gate constant current source of Comparative Example 2 are also shown for reference. Configurations that are the same as or similar to those in Figures 1 and 2 will be described as necessary.

[0026] Table 1 shows the channel widths and gate lengths of the transistors included in the single-gate constant current source of Comparative Example 1, the channel widths and gate lengths of the first and second transistors included in the double-gate constant current source of Comparative Example 2, the channel widths and gate lengths of the first transistor 100 included in the constant current source 11 of this embodiment (embodiment 1), and the channel widths and gate lengths of the second transistor 110 included in the constant current source 11 of this embodiment (embodiment 1).

[0027] [Table 1]

[0028] As shown in Table 1, the channel width and gate length of the transistor of Comparative Example 1 are, for example, channel width W and gate length L. Also, the channel width and gate length of each of the first transistor and the second transistor of Comparative Example 2 are, for example, channel width W and gate length L. On the other hand, the channel width and gate length of the first transistor 100 of the first embodiment are, for example, channel width W1 and gate length L1, and the channel width and gate length of the second transistor 110 of the first embodiment are, for example, channel width W2 and gate length L2. Note that in the first embodiment, the gate length L1 is the same as the gate length L2. The channel width W1 may be called the first channel width, the channel width W2 may be called the second channel width, the gate length L1 may be called the first gate length L1, and the gate length L2 may be called the second gate length.

[0029] Using a numerical value N (N>0) and a reference channel width W3, the channel width W1 is expressed by the following formula (1), and the channel width W2 is expressed by the following formula (2).

[0030]

number

[0031]

number

[0032] When the thin-film transistor operates in the saturation region, a drain current Idss expressed by the following formula (3) flows from the drain terminal to the source terminal of the thin-film transistor. When the thin-film transistor operates in the linear region, a drain current Idsl expressed by the following formula (4) flows from the drain terminal to the source terminal of the thin-film transistor.

[0033]

number

[0034]

number

[0035] In formula (3) and formula (4), the capacitance C ox is the capacitance of the gate insulating film per unit area, the mobility μ is the mobility of electrons, and the threshold voltage V th are the threshold voltage, channel width W, and gate length L of the thin film transistor. Similarly to the constant current source 11 described with reference to FIG. 2, voltage Vgs is the gate-source voltage of the thin film transistor, and voltage Vds is the drain-source voltage of the thin film transistor.

[0036] <1-2-1. Electrical characteristics of Comparative Example 1> Consider the case where the transistor of the single-gate constant current source of Comparative Example 1 operates in the saturation region. In this case, the drain current Idss expressed by the formula (3) flows from the drain terminal to the source terminal of the thin film transistor. That is, the single-gate constant current source can pass the drain current Idss expressed by the formula (3).

[0037] 3 is a diagram showing, for example, the dependency of the drain current ID on the drain voltage VD of the single-gate constant current source of Comparative Example 1. At the boundary between the linear region and the saturated region, the source-drain voltage Vds (VD) is equal to the difference between the voltage Vgs and the threshold voltage Vth, i.e., Vgs-Vth.

[0038] As shown in FIG. 3, the drain current Idss of Comparative Example 1 (Prior Art 1) is ideally a current that does not depend on the drain voltage VD, and is called a so-called saturation current, constant current, or the like.

[0039] Figure 4 shows the result of actual measurement showing the dependency of the drain current ID on the drain voltage VD. The normalized drain current Ids (Ids [au]) shown in Figure 4 is the drain current Ids measured when the gate-source voltage Vgs is 4V normalized by the drain current when the drain-source voltage Vds is 4V.

[0040] 4, in the constant current source of Comparative Example 1 (Prior Art 1) with channel width W / gate length L=9 μm / 6 μm, the drain voltage increases rapidly with an increase in drain voltage Vds, and the kink characteristics are not suppressed. Even when the gate length L is doubled to 12 μm, the kink characteristics are not sufficiently suppressed.

[0041] <1-2-2. Electrical characteristics of Comparative Example 2> Consider the case where the transistor of the double-gate constant current source of Comparative Example 2 operates in the saturation region. In this case, the drain current Idss expressed by the formula (3) flows from the drain terminal to the source terminal of the thin film transistor. In other words, the single-gate constant current source can pass the drain current Idss expressed by the formula (3).

[0042] Consider a case where the double-gate constant current source of Comparative Example 2 operates in the same manner as the transistor of the single-gate constant current source of Comparative Example 1. In this case, the second transistor operates in the saturation region, and a drain current Idss expressed by equation (3) flows from the drain terminal to the source terminal of the second transistor. Also, the first transistor operates in the linear region, and a drain current Idsl expressed by equation (4) flows from the drain terminal to the source terminal of the first transistor.

[0043] 2, the voltage Vs of the double-gate constant current source of Comparative Example 2 is 0V, the voltage Vgs in Equation (3) is the voltage Vg-voltage Vm, and the voltage Vds is the voltage Vd-voltage Vm. Also, the voltage Vgs in Equation (4) is the voltage Vg, and the voltage Vds is the voltage Vm.

[0044] The channel width W and gate length L of the first and second transistors of Comparative Example 2 are the same as the channel width W and gate length L of the transistor of the single-gate constant current source. ox is the capacitance of the gate insulating film per unit area, μ is the electron mobility, Vth are the respective threshold voltages of the first transistor and the second transistor.

[0045] In addition, the currents flowing through the first and second transistors of the double-gate constant current source are the same, and the drain current Idss is the same as the drain current Idsl. If we assume that formulas (3) and (4) are equal and calculate the drain current Idsp2 using formulas (3) and (4), the drain current Idsp2 can be expressed by formula (5). That is, the double-gate constant current source can pass the drain current Idsp2 expressed by formula (5).

[0046]

number

[0047] As shown in FIG. 4, the constant current source of Comparative Example 2 (Prior Art 2) having a first transistor channel width W / gate length L=9 μm / 6 μm and a second transistor channel width W / gate length L=9 μm / 6 μm is able to suppress the kink characteristics more than the constant current source of Comparative Example 1.

[0048] On the other hand, the drain current Idsp2 shown in formula (5) is 1 / 2 (half) of the drain current Idss shown in formula (3). That is, as shown in FIG. 3, the double-gate constant current source of Comparative Example 2 can only pass half the current of the single-gate constant current source of Comparative Example 1.

[0049] <1-2-3. Electrical characteristics of constant current source 11> Based on the formulas (1) and (2), the channel width W2 of the second transistor 110 of the constant current source 11 is N times the channel width W1 of the first transistor 100. By making the channel width W2 of the second transistor 110 larger than the channel width W1 of the first transistor 100, the voltage Vm of the intermediate electrode MID becomes larger than the voltage Vm of the intermediate electrode MID of Comparative Example 2. As a result, the first transistor 100 can operate in a linear region closer to the saturation region.

[0050] As in Comparative Example 2, the voltage Vm and the drain current Idse of the constant current source 11 are calculated assuming that the currents flowing through the first transistor 100 and the second transistor 110 of the constant current source 11 are the same. The voltage Vm can be expressed by formula (6), and the drain current Idse can be expressed by formula (7). That is, the constant current source 11 can pass the drain current Idse expressed by formula (7).

[0051]

number

[0052]

number

[0053] The drain current Idse of the constant current source 11 is N / (1+N) times the drain current Idss shown in equation (3).

[0054] Furthermore, the difference between the drain current Idse and the drain current Idss (change in drain current) associated with an increase in voltage Vm is 1-N / (1+N)=1 / (1+N). If the drain current Idse is adjusted to be the same as the drain current Idss, with channel width W / gate length L as one unit, the effect of the change in drain current is 1 / N. In other words, the change in drain current is 1+1 / N=(1+N) / N.

[0055] This means that, when the numerical value N is one unit of channel width W / gate length L, formula (1) and formula (2) express that the channel width / gate length L of the first transistor 100 and the channel width / gate length L of the second transistor 110 are (1+N) / N:(1+N). That is, the value obtained by dividing the channel width W2 by the second gate length L2 is equal to or greater than the value obtained by dividing the channel width W1 by the first gate length L1. For example, when N=2, the change in the drain current is 1.5 times, and when N=4, the change in the drain current is 1.25 times.

[0056] For example, when N=1, the ratio (W ratio) of the channel width W1 of the first transistor 100 to the channel width W2 of the second transistor 110 is 2:2. When the reference channel width W3 is, for example, 4 μm (W3=4), the channel width W1 of the first transistor 100 is 8 μm, and the channel width W2 of the second transistor 110 is 8 μm. When N=4, the ratio of the channel width W1 of the first transistor 100 to the channel width W2 of the second transistor 110 is 1.25:5. When the reference channel width W3 is, for example, 4 μm (W3=4), the channel width W1 of the first transistor 100 is 5 μm, and the channel width W2 of the second transistor 110 is 20 μm. As an example, when the reference channel width W3 is 4 μm, the W ratio, the channel width W1 of the first transistor 100, and the channel width W2 of the second transistor 110 are shown in Table 2. The channel length L1=L2 is, for example, 6 μm. The reference channel width W3, the channel length L1, and the channel length L2 described here are examples, and the reference channel width W3, the channel length L1, and the channel length L2 are not limited to the values ​​described here. The respective values ​​of the reference channel width W3, the channel length L1, and the channel length L2 may be appropriately set to satisfy the respective formulas according to the application and specifications of the semiconductor device 10 or the constant current source 11 including the semiconductor device 10.

[0057] [Table 2]

[0058] The drain current Idss is an ideal saturation current, and the smaller the change in the drain current is, that is, the larger the value N is, the closer the drain current Idse of the constant current source 11 is to the ideal saturation current. In other words, by adjusting the value N, the drain current Idse of the constant current source 11 can be adjusted to the ideal saturation current.

[0059] For example, when the reference channel width W3 is 3 μm (W3=3) and the value N is 2 (N=2), the channel width W1 of the first transistor 100 is 4.5 μm, and the channel width W2 of the second transistor 110 is 9 μm. As shown in FIG. 4, the constant current source 11 of the embodiment 1 (Embodiment 1 N=2) can suppress the kink characteristics more than the drain current of the constant current source of the comparative example 1 and the constant current source of the comparative example 2.

[0060] Also, for example, when the reference channel width W3 is 3.6 μm (W3=3.6) and the value N is 4 (N=4), the channel width W1 of the first transistor 100 is 4.5 μm, and the channel width W2 of the second transistor 110 is 18 μm. As shown in Fig. 4, the constant current source 11 of embodiment 1 (N=4) can suppress the kink characteristics more than the constant current source 11 when N=2. That is, as the value N becomes larger, the kink characteristics of the constant current source 11 are suppressed.

[0061] When N=4, the drain current Idse shown in formula (7) is 4 / 5 (80%) of the drain current Idss shown in formula (3). That is, as shown in FIG. 3, the constant current source 11 of embodiment 1 (N=4) can pass more current than the double-gate constant current source of comparative example 2.

[0062] The constant current source 11 including the semiconductor device 10 is a double-gate transistor including a first transistor 100 and a second transistor 110. The channel width W2 / gate length L2 of the second transistor 110 is larger than the channel width W1 / gate length L1 of the first transistor 100, and the saturation current characteristics of the constant current source 11 are improved compared to the conventional constant current sources of Comparative Example 1 and Comparative Example 2. Since the constant current source 11 is a circuit capable of suppressing a sudden increase in drain current, the saturation current characteristics can be improved and the circuit including the constant current source 11 can suppress an increase in current consumption.

[0063] <1-3. Examples of layout and cross-sectional structure of semiconductor device 10> An example of the layout and cross-sectional structure of the semiconductor device 10 will be described with reference to Fig. 5 to Fig. 8. Fig. 5, Fig. 7 and Fig. 8 are diagrams showing an example of the layout of the semiconductor device 10. Fig. 6 is a cross-sectional view showing the cross-sectional structure taken along A1-A2 in Fig. 5. Configurations that are the same as or similar to those in Fig. 1 to Fig. 4 will be described as necessary.

[0064] Here, an example will be described in which the semiconductor device 10 and the constant current source 11 including the semiconductor device 10 are configured using thin film transistors (Thin Film Transistors (TFTs)). The semiconductor device 10 and the constant current source 11 including the semiconductor device 10 may be configured using transistors other than thin film transistors. For example, the semiconductor device 10 and the constant current source 11 including the semiconductor device 10 may be configured using transistors formed using a Si wafer, an SOI substrate, or the like.

[0065] First, an example of the layout of the semiconductor device 10 when N=4 will be described with reference to FIG. 5. FIG. 5 is a diagram showing an example of the layout of the semiconductor device 10 when N=4, in which the channel width W1 of the first transistor 100 is 1.25×W3 (reference channel width W3), and the channel width W2 of the second transistor 110 is 5×W3. In the example shown in FIG. 5, the gate length L1 of the first transistor 100 is the same as the gate length L2 of the second transistor 110. Note that FIG. 5 is a diagram showing a schematic diagram of the output signal line 16, the input signal line 12, and the first voltage supply wiring 14, as well as an example of the constant current source 11 including the semiconductor device 10.

[0066] As shown in FIG. 5, the first transistor 100 includes a second conductive film 31a, a first opening 39a, a first conductive film 34a, and a semiconductor film 32a. The second conductive film 31a corresponds to the source electrode 104, and the first conductive film 34a corresponds to the gate electrode 102. The semiconductor film 32a includes a portion corresponding to the drain electrode 106. The second transistor 110 includes a second conductive film 31b, a plurality of first openings 39b, 39c, and 39d, a first conductive film 34b, and a semiconductor film 32b. The second conductive film 31b corresponds to the drain electrode 116, and the first conductive film 34b corresponds to the gate electrode 112. The semiconductor film 32b includes a portion corresponding to the source electrode 114. The drain electrode 106 and the source electrode 114 are provided to be located between the first conductive film 34a and the first conductive film 34b.

[0067] The semiconductor film 32a is connected to the semiconductor film 32b to form one pattern (semiconductor film 32). The width of the semiconductor film 32a along the direction in which the first conductive film 34a extends is a channel width W1, and the width of the semiconductor film 32b along the direction in which the first conductive film 34b extends is a channel width W2. That is, the semiconductor film 32 is one pattern having two different channel widths. The channel width W1 of the semiconductor film 32a includes the first end 32aa and the second end 32ab, and the channel width W2 of the semiconductor film 32b includes the first end 32ba and the second end 32bb. The first end 32aa and the first end 32ba are arranged to be located on the same straight line, and the second end 32ab and the second end 32bb are arranged to be located on different straight lines. Also, a part of the first end 32aa, a part of the first end 32ba, a part of the second end 32ab, and a part of the second end 32bb are disposed so as to be located between the first conductive film 34a and the first conductive film 34b. Note that the semiconductor film 32 includes channels that become current paths of the first transistor 100 and the second transistor 110, and may be called an active layer.

[0068] For example, the semiconductor device 10 and the constant current source 11 including the semiconductor device 10 include one transistor including two gate electrodes: a gate electrode 102 (first gate electrode) having a gate length L1 (first gate length) overlapping with a semiconductor film 32a (first active layer) having a channel width W1 (first channel width W1), and a gate electrode 112 (second gate electrode) having a gate length L2 (second gate length) overlapping with a semiconductor film 32b (second active layer) formed continuously with the semiconductor film 32a having the channel width W1.

[0069] Furthermore, the constant current source 11 including the semiconductor device 10 includes, for example, a first voltage supply wiring 14 connected to the second conductive film 31a, an input signal line 12 connected to the first conductive films 34a and 34b, and an output signal line 16 connected to the second conductive film 31b.

[0070] For example, when N=4 and the reference channel width W3 is 4 μm, the channel width W1 / gate length L1 of the first transistor 100 of the constant current source 11 including the semiconductor device 10 is 5 μm / 6 μm, and the channel width W2 / gate length L2 of the second transistor 110 is 20 μm / 6 μm. It is considered that the electrical characteristics of the constant current source 11 including the semiconductor device 10 when N=4 and the reference channel width W3 is 4 μm are approximately the same as the electrical characteristics of the single-gate constant current source of Comparative Example 1 when the channel length W / gate length L is 20 μm / 30 μm. However, it is considered that the layout area of ​​the single-gate constant current source of Comparative Example 1 in this case is larger than the layout area of ​​the constant current source 11 including the semiconductor device 10 by, for example, about 30%.

[0071] Therefore, the constant current source 11 including the semiconductor device 10 can reduce the layout area as compared to the constant current source of the first comparative example.

[0072] Next, a cross-sectional structure of the semiconductor device 10 will be described with reference to Fig. 6. Fig. 6 is a diagram showing an example in which the semiconductor device 10 is included in a display device 300. The display device 300 shown in Fig. 6 is, for example, a liquid crystal display device.

[0073] The display device 300 includes, for example, a first substrate 120, a TFT array layer 30, a wiring layer 40, an electrode layer 48, a first alignment film 50, a liquid crystal layer 60, a second alignment film 70, an overcoat layer 150, a color filter layer 80, and a second substrate 90.

[0074] On the first substrate 120, a TFT array layer 30 and a wiring layer 40 are provided.

[0075] The TFT array layer 30 includes an undercoat film 160, a semiconductor film 32, a gate insulating film 33, first conductive films 34a and 34b, an insulating film 35, second conductive films 31a and 31b, first openings 39a, 39b, 39c and 39d, and an organic film 38.

[0076] The base film 160 is provided on the first substrate 120. The semiconductor film 32 is provided on the base film 160. The semiconductor film 32 includes a semiconductor film 32a of the first transistor 100 and a semiconductor film 32b of the second transistor 110. The semiconductor films of the thin film transistors included in the display device 300 are provided in the same layer as the semiconductor film 32. The display device 300 includes an n-type thin film transistor and a p-type thin film transistor, and the first transistor 100 and the second transistor 110 are, for example, n-type thin film transistors. The material forming the semiconductor film 32 is, for example, polysilicon.

[0077] The gate insulating film 33 is provided so as to cover the semiconductor film 32. The first conductive film 34a, the first conductive film 34b, and the input signal line 12 are provided on the gate insulating film 33. The first conductive film 34a is the gate electrode 102 of the first transistor 100, and the first conductive film 34b is the gate electrode 112 of the second transistor 110. The first conductive film 34a, the first conductive film 34b, and the input signal line 12 are a first conductive film. The material forming the first conductive film is, for example, a metal such as titanium (Ti), aluminum (Al), copper (Cu), tungsten (W), or tantalum (Ta), or an alloy thereof.

[0078] The insulating film 35 is provided so as to cover the first conductive film 34a, the first conductive film 34b, and the input signal line 12. The material forming the insulating film 35 is an inorganic insulator such as silicon nitride (SiN), silicon oxide (SiO2), or silicon oxynitride (SiON).

[0079] The first opening 39a opens the gate insulating film 33 and the insulating film 35, and electrically connects the semiconductor film 32a and the second conductive film 31a. The first openings 39b, 39c, and 39d are openings for opening the gate insulating film 33 and the insulating film 35, for example, and electrically connecting the semiconductor film 32b and the second conductive film 31b.

[0080] Although not shown, the TFT array layer 30 includes a second opening. The second opening is an opening for opening the insulating film 35 and electrically connecting the first conductive film and the second conductive film.

[0081] The second conductive films 31a and 31b are provided on the upper surface of the insulating film 35, and on the side and bottom surfaces of the first opening (side surfaces of the insulating film 35 and side surfaces of the gate insulating film 33). The first voltage supply wiring 14 and the output signal line 16 are also provided in the same layer as the second conductive films 31a and 31b. The second conductive film can be made of the same material as the first conductive film.

[0082] The organic film 38 is provided so as to cover the second conductive film. The material for forming the organic film 38 is, for example, a polyimide-based or acrylic resin. The organic film 38 using the polyimide-based or acrylic resin can reduce unevenness that occurs when films, wiring, transistors, and the like in layers below the organic film 38 are formed.

[0083] The method for forming the TFT array layer 30, the structure of the transistors, and the respective films, layers, and members may employ methods and members commonly used in the technical field of the present invention.

[0084] The wiring layer 40 is provided on the organic film 38. The wiring layer 40 includes a third conductive film (not shown) and an insulating film 49. The insulating film 49 is provided so as to cover the third conductive film. The third conductive film is, for example, a film that forms a capacitance wiring that supplies a voltage to the capacitance of a plurality of pixels included in the display device 300. The third conductive film can be made of the same material as the first conductive film, and the insulating film 49 can be made of the same material as the insulating film 35 or can be made of the same material as the organic film 38.

[0085] An electrode layer 48 is provided on the insulating film 49. The electrode layer 48 includes, for example, a fourth conductive film (not shown) and an insulating film 45. The insulating film 45 is provided so as to cover the fourth conductive film. The fourth conductive film is, for example, a film that forms the capacitance wiring, each electrode, a power supply line, wiring that connects the wirings to each other, and the like. The material that forms the fourth conductive film can be a transparent conductive film, a thin film of a conductive metal material, or the like. The transparent conductive film is, for example, ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). The thin film of the conductive metal material is, for example, a thin film made of aluminum (Al), titanium (Ti), tungsten (W), or the like. The material that forms the insulating film 45 can be the same as the material that forms the insulating film 35 and the organic film 38.

[0086] Further, pixel electrodes (not shown) included in each of the plurality of pixels are provided on the insulating film 45. The pixel electrodes are electrically connected to a second conductive film (not shown) forming a drain electrode of a transistor included in the pixel, for example, through an opening (not shown) that opens the insulating film 45, the insulating film 49, and the organic film 38. The opening that opens the insulating film 45, the insulating film 49, and the organic film 38 may open the fourth conductive film and the third conductive film. A first alignment film 50 is applied so as to cover the plurality of pixel electrodes. The first alignment film 50 is formed of a material that exhibits horizontal alignment properties, and is disposed on the surface of the first substrate 120 that faces the liquid crystal layer 60. The material that forms the pixel electrodes can be, for example, a transparent conductive film similar to the material that forms the fourth conductive film. The material that forms the first alignment film 50 can be, for example, a resin such as a polyimide resin.

[0087] For example, the first substrate 120 side of the liquid crystal layer 60 of the display device 300 is called the TFT array side substrate, and the second substrate 90 side is called the opposing substrate. The opposing substrate includes a second alignment film 70, an overcoat layer 150, a color filter layer 80, and a second substrate 90. The color filter layer 80, the overcoat layer 150, and the second alignment film 70 are provided on the second substrate 90 in this order. The color filter layer 80 includes, for example, a color filter layer that emits red, a color filter layer that emits green, and a color filter layer that emits blue. The second alignment film 70 faces the first alignment film 50 with the liquid crystal layer 60 sandwiched therebetween. The material for forming the second alignment film 70 can be, for example, a polyimide-based resin similar to that of the first alignment film 50. The overcoat layer 150 can be, for example, an organic resin.

[0088] Next, an example of the layout of the semiconductor device 10 when N=4 will be described with reference to Fig. 7. The layout shown in Fig. 7 differs from the layout shown in Fig. 5 in the arrangement of the semiconductor film 32a and the semiconductor film 32b in the semiconductor film 32. Other points of the layout shown in Fig. 7 are the same as the layout shown in Fig. 5. Therefore, in the description of the layout shown in Fig. 7, the same contents as those of the layout shown in Fig. 5 will be described as necessary.

[0089] 7, the first end 32aa and the first end 32ba are disposed so as to be located on different straight lines, and the second end 32ab and the second end 32bb are disposed so as to be located on different straight lines. In addition, a part of the first end 32aa, a part of the first end 32ba, a part of the second end 32ab, and a part of the second end 32bb are disposed so as to be located between the first conductive film 34a and the first conductive film 34b.

[0090] Next, an example of the layout of the semiconductor device 10 when N=1 will be described with reference to Fig. 8. The layout shown in Fig. 8 differs from the layout shown in Fig. 5 in that N=1 and in the arrangement of the semiconductor films 32a and 32b in the semiconductor film 32. Other points of the layout shown in Fig. 8 are the same as those of the layout shown in Fig. 5. Therefore, in the description of the layout shown in Fig. 8, the same contents as those of the layout shown in Fig. 5 will be described as necessary.

[0091] 8, the channel width W1 of the first transistor 100 and the channel width W2 of the second transistor 110 are 2×W3 (reference channel width W3). In the semiconductor device 10 shown in FIG 8, the gate length L1 of the first transistor 100 is the same as the gate length L2 of the second transistor 110, similar to the layout shown in FIG 5.

[0092] 8, the first end 32aa and the first end 32ba are arranged to be located on the same straight line, and the second end 32ab and the second end 32bb are arranged to be located on the same straight line. Also, a part of the first end 32aa, a part of the first end 32ba, a part of the second end 32ab, and a part of the second end 32bb are arranged to be located between the first conductive film 34a and the first conductive film 34b.

[0093] As described above, the semiconductor device 10 according to the first embodiment and the constant current source 11 including the semiconductor device 10 are capable of improving saturation current characteristics, suppressing an increase in current consumption, and reducing the layout area.

[0094] <2. Second embodiment> An overview of an operational amplifier 21 according to the second embodiment will be described with reference to Fig. 9. Configurations that are the same as or similar to those in Figs. 1 to 8 will be described as necessary.

[0095] 9 is a circuit diagram showing a configuration of the operational amplifier 21. The operational amplifier 21 includes a first amplifier circuit 202 and a second amplifier circuit 204. The first amplifier circuit 202 may be called an input stage of the operational amplifier 21, and the second amplifier circuit 204 may be called an output stage of the operational amplifier 21. Note that the operational amplifier 21 includes a two-stage amplifier circuit as an example, but the amplifier circuit is not limited to two stages. The operational amplifier 21 may include, for example, three or more stages of amplifier circuits. The number of stages of the amplifier circuit of the operational amplifier 21 may be set appropriately depending on the application and specifications of the operational amplifier 21.

[0096] The first amplifier circuit 202 includes the semiconductor device 10A, a differential amplifier section 212, and a current mirror section 214. The second amplifier circuit 204 includes the semiconductor device 10B, and a source-grounded amplifier section 222. Although details will be described later, the semiconductor device 10A and the semiconductor device 10B have the same configuration as the semiconductor device 10 described in the "first embodiment." That is, the operational amplifier 21 includes a plurality of semiconductor devices 10. The semiconductor device 10A may be called the first semiconductor device, and the semiconductor device 10B may be called the second semiconductor device. The configurations of the semiconductor device 10A and the semiconductor device 10B will be described as necessary.

[0097] The semiconductor device 10A includes a first transistor 100A and a second transistor 110A. The first transistor 100A and the second transistor 110A are n-type transistors. The semiconductor device 10A is a single transistor having a double gate. As in the semiconductor device 10, the first transistor 100A and the second thin film transistor 110A are, for example, n-type thin film transistors. The semiconductor device 10A is electrically connected between the first voltage supply wiring 14 and the output signal line 16A, and the gate electrode of the semiconductor device 10A is electrically connected to the input signal line 12. An input signal IN1 is supplied to the input signal line 12, a common voltage VL is supplied to the first voltage supply wiring 14, and an output signal OUT1 is supplied to the output signal line 16A.

[0098] The differential amplifier 212 includes a first transistor 20A and a second transistor 20B. The first transistor 20A includes a first transistor 200A and a second transistor 210A that share a gate electrode and are electrically connected to each other. That is, the first transistor 20A is a single transistor having a double gate. The second transistor 20B includes a first transistor 200B and a second transistor 210B that share a gate electrode and are electrically connected to each other, similar to the first transistor 20A. That is, the second transistor 20B is a single transistor having a double gate. The first transistor 200A, the second transistor 210A, the first transistor 200B, and the second transistor 210B are n-type thin film transistors.

[0099] The first transistor 20A is electrically connected between the output signal line 16A and a first node 24, and the gate electrode of the first transistor 20A is electrically connected to the first input signal line 18. An output signal OUT1 is provided to the output signal line 16A, a first input signal S1 is provided to the first input signal line 18, and an output signal OUT2 is provided to the first node 24.

[0100] The second transistor 20B is electrically connected between the output signal line 16A and a second node 26, and the gate electrode of the second transistor 20B is electrically connected to a second input signal line 22. An output signal OUT1 is supplied to the output signal line 16A, a second input signal S2 is supplied to the second input signal line 22, and an output signal OUT3 is supplied to the second node 26.

[0101] The current mirror section 214 includes a third transistor 25A and a fourth transistor 25B. The third transistor 25A includes a first transistor 250A and a second transistor 260A that share a gate electrode and are electrically connected to each other, similar to the first transistor 20A. That is, the third transistor 25A is one transistor having a double gate. The fourth transistor 25B includes a first transistor 250B and a second transistor 260B that share a gate electrode and are electrically connected to each other, similar to the first transistor 20A. That is, the fourth transistor 25B is one transistor having a double gate. The first transistor 250A, the second transistor 260A, the first transistor 250B, and the second transistor 260B are p-type thin film transistors.

[0102] The third transistor 25A is electrically connected between the first node 24 and the second voltage supply wiring 28, and the gate electrode of the third transistor 25A is electrically connected to the first node 24. The output signal OUT2 is supplied to the first node 24, and the power supply voltage VH is supplied to the second voltage supply wiring 28. The power supply voltage VH is, for example, a voltage VDD. The voltage VDD is higher than the common voltage VL, and may be, for example, 3 V, 3.3 V, 5 V, 12 V, or 15 V. The power supply voltage VH may be set appropriately depending on the application and specifications of the operational amplifier 21.

[0103] The fourth transistor 25B is electrically connected between the second node 26 and the second voltage supply wiring 28, and the gate electrode of the fourth transistor 25B is electrically connected to the first node 24. An output signal OUT2 is supplied to the first node 24, a power supply voltage VH is supplied to the second voltage supply wiring 28, and an output signal OUT3 is supplied to the second node 26.

[0104] When the third transistor 25A is formed, for example, with the same channel width and gate length as the fourth transistor 25B, the current flowing through the first node 24 flows to the second node 26, and an output signal OUT3 corresponding to the output signal OUT2 is output to the second node 26.

[0105] The semiconductor device 10B includes a first transistor 100B and a second transistor 110B. The first transistor 100B and the second transistor 110B are n-type transistors. The semiconductor device 10B is a single transistor having a double gate. The semiconductor device 10B is electrically connected between a first voltage supply wiring 14 and an output signal line 16B, and the gate electrode of the semiconductor device 10B is electrically connected to an input signal line 12. An input signal IN1 is supplied to the input signal line 12, a common voltage VL is supplied to the first voltage supply wiring 14, and an output signal OUT4 is supplied to the output signal line 16B.

[0106] The common-source amplifier 222 includes a fifth transistor 25C. Like the fourth transistor 25B, the fifth transistor 25C includes a first transistor 250C and a second transistor 260C that share a gate electrode and are electrically connected to each other. That is, the fifth transistor 25C is a single transistor having a double gate. The first transistor 250C and the second transistor 260C are p-type thin film transistors.

[0107] The fifth transistor 25C is electrically connected between the output signal line 16B and the second voltage supply wiring 28, and the gate electrode of the fifth transistor 25C is electrically connected to the second node 26. An output signal OUT3 is supplied to the second node 26, a power supply voltage VH is supplied to the second voltage supply wiring 28, and an output signal OUT4 is supplied to the output signal line 16B.

[0108] When the third transistor 25A is formed with, for example, the same channel width and gate length as the fourth transistor 25B, the current flowing through the first node 24 flows to the second node 26, and an output signal OUT3 corresponding to the output signal OUT2 is output to the second node 26. That is, the first amplifier circuit 202 outputs an output signal OUT3 corresponding to the output signal OUT2 to the second amplifier circuit 204. In addition, the second amplifier circuit 204 outputs an output signal OUT4 corresponding to the output signal OUT3.

[0109] In addition, a configuration similar to that of the semiconductor device 10 may be applied to each of the first transistor 20A, the second transistor 20B, the third transistor 25A, the fourth transistor 25B, and the fifth transistor 25C, or to a part of the first transistor 20A, the second transistor 20B, the third transistor 25A, the fourth transistor 25B, and the fifth transistor 25C.

[0110] The operational amplifier 21 includes the semiconductor device 10A, and can cause a stable current to flow to the second node 26 of the first amplifier circuit 202. Moreover, the operational amplifier 21 includes the semiconductor device 10B, and can cause a stable current to flow to the output signal line 16B of the second amplifier circuit 204, and can output a stable output signal OUT4 corresponding to the output signal OUT3. Moreover, an increase in the current consumption of the operational amplifier 21 can be suppressed, and the layout area of ​​the operational amplifier 21 can be reduced.

[0111] <3. Third embodiment> An overview of the display device 300 will be described with reference to Figures 10 and 11. Configurations that are the same as or similar to those in Figures 1 to 9 will be described as necessary.

[0112] 10 and 11 are top views showing the configuration of the display device 300. The display device 300 has a configuration similar to that of the display device 300 described in "1-3. Examples of layout and cross-sectional structure of the semiconductor device 10" and is, for example, a liquid crystal display device. Although details will be described later, the same configuration and function as the operational amplifier 21 including the semiconductor device 10 are included in, for example, a control circuit 330 and a second drive circuit 320. In addition, the same configuration and function as the operational amplifier 21 including the semiconductor device 10 may be included in a first drive circuit 310 or an IC chip 370.

[0113] 10, the display device 300 includes a first substrate 120, a seal portion 340, a second substrate 90, a flexible printed circuit board 360 (FPC360), and an IC chip 370. The first substrate 120 and the second substrate 90 are bonded together by the seal portion 340. In a display region 322 surrounded by the seal portion 340, a plurality of pixels 380 are arranged in a matrix in the directions D1 and D2. The display region 322 is an area that overlaps with the liquid crystal layer 60 (FIG. 6) in a plan view.

[0114] The peripheral region 321 includes a seal region 324 and a terminal region 326. The peripheral region 321 is a region around the display region 322 and surrounds the display region 322. The seal region 324 is a region around the display region 322 that overlaps with the seal portion 340 in a plan view. The terminal region 326 is a region where the first substrate 120 is exposed from the second substrate 90, and is provided outside the seal region 324. Note that the outside of the seal region 324 means the outside of the region surrounded by the seal portion 340. The FPC 360 is provided in the terminal region 326. The IC chip 370 is provided on the FPC 360, for example. The IC chip 370 supplies control signals for driving each pixel 380.

[0115] 11, a first driving circuit 310 is provided parallel to the direction D1 of the display area 322. Also, a second driving circuit 320 is provided parallel to the direction D2 of the display area 322. The first driving circuit 310 and the second driving circuit 320 are provided in the sealing area 324 (FIG. 10).

[0116] The first drive circuit 310 is, for example, a source driver and may include a multiplexer circuit that selects a data signal. The second drive circuit 320 is, for example, a gate driver circuit.

[0117] The pixels 380 are arranged, for example, in a stripe array. Each of the pixels 380 may correspond to, for example, a sub-pixel R, a sub-pixel G, or a sub-pixel B. One pixel may be formed of three sub-pixels. The pixel 380 is the smallest unit constituting a part of an image reproduced in the display region 322. Each of the pixels 380 is provided with one display element (not shown). In the example shown in FIG. 10, the display element is a liquid crystal element. The color corresponding to the sub-pixel is determined by the characteristics of the liquid crystal element or a color filter (not shown) provided in the sub-pixel.

[0118] In addition, in the stripe arrangement, the sub-pixels R, G, and B can be configured to give different colors from one another. For example, the sub-pixels R, G, and B can be provided with color filters (not shown) that emit the three primary colors of red, green, and blue, respectively. For example, the sub-pixel R may be provided with a red color filter that emits red color, the sub-pixel G may be provided with a green color filter that emits green color, and the sub-pixel B may be provided with a blue color filter that emits blue color. An arbitrary voltage or current is supplied to each of the three sub-pixels, and the display device 300 can display an image.

[0119] A plurality of data signal lines including a data signal line 331 extend from the first drive circuit 310 in the D2 direction and are connected to a plurality of pixels 380 arranged in the D2 direction. A plurality of scanning signal lines including a scanning signal line 329 extend from the second drive circuit 320 in the D1 direction and are connected to a plurality of pixels 380 arranged in the D1 direction.

[0120] A terminal section 350 is provided in the terminal region 326. The terminal section 350 and the first drive circuit 310 are connected by a connection wiring 341. Similarly, the terminal section 350 and the second drive circuit 320 are connected by a connection wiring 341. By connecting the FPC 360 to the terminal section 350, an external device to which the FPC 360 is connected is connected to the display device 300, and a signal from the external device is supplied to, for example, the IC chip 370, the first drive circuit 310, the second drive circuit 320, the control circuit 330, and each pixel 380. The display device 300 drives each pixel 380 provided in the display device 300 using the signal from the external device and the control signal generated by the IC chip 370, the first drive circuit 310, and the second drive circuit 320.

[0121] For example, the control circuit 330 includes an operational amplifier 21B including the semiconductor device 10. The control circuit 330 can shape a signal from an external device based on the operational amplifier 21B, and generate a stable voltage. As a result, the control circuit 330 can supply the shaped signal and the stable voltage to, for example, the first drive circuit 310 and the second drive circuit 320.

[0122] Also, for example, the second drive circuit 320 includes an operational amplifier 21A including the semiconductor device 10. The second drive circuit 320 can shape a signal from an external device based on the operational amplifier 21A and generate a stable voltage. As a result, the second drive circuit 320 can supply the shaped signal and stable voltage to a circuit inside the second drive circuit 320, and can operate stably using the shaped signal and stable voltage. Also, the second drive circuit 320 can supply a shaped control signal to, for example, a scanning signal line 329. In other words, the operational amplifier 21A is electrically connected to the scanning signal line 329 and can supply the shaped control signal to the scanning signal line 329 and a plurality of pixels 380 electrically connected to the scanning signal line 329.

[0123] Also, for example, the first drive circuit 310 may include a constant current source 11 (FIG. 2) including the semiconductor device 10. The first drive circuit 310 can shape the data signal and the control signal supplied from the IC chip 370 based on the constant current source 11. As a result, the first drive circuit 310 can supply the shaped control signal to a circuit inside the first drive circuit 310, and can operate stably using the shaped control signal. Also, the first drive circuit 310 can supply the shaped data signal to, for example, a data signal line 331.

[0124] Each of the pixels 380 includes, for example, a transistor (not shown), a liquid crystal element (not shown), and a capacitance element (not shown). The liquid crystal element and the capacitance element are electrically connected to the transistor. The transistor is electrically connected to a scanning signal line 329 and a data signal line 331. The capacitance element is electrically connected, for example, between a pixel electrode and a capacitance wiring 346. The liquid crystal element includes, for example, a pixel electrode (not shown), a common electrode (not shown), and liquid crystal molecules included in the liquid crystal layer 60. The common electrode is electrically connected to a common wiring 345. For example, the pixel electrode is provided on the organic film 45 (FIG. 6). The wiring layer 40 (FIG. 6) includes the capacitance wiring 346, and the electrode layer 48 (FIG. 6) includes the common electrode and the common wiring.

[0125] For example, the control circuit 330 supplies a common voltage to the capacitance wiring 346 and the common wiring 345. The common voltage may be, for example, a voltage between the voltage of the positive voltage amplitude of the data signal and the voltage of the negative voltage amplitude of the data signal, a voltage that is a reference voltage for the voltage amplitude, 0V, a ground voltage, or a ground voltage. The common wiring 345 is electrically connected to the common electrode via a plurality of connection parts 343, so that the liquid crystal element is electrically connected to the common electrode. The first driving circuit 310, the second driving circuit 320, and the control circuit 330 can change the alignment state of the liquid crystal molecules by supplying a current or a voltage to each of the pixel electrode and the common electrode. As a result, the display device 300 can display an image.

[0126] As described above, the display device 300 includes a constant current source including the semiconductor device 10, and can perform stable operation using the constant current source including the semiconductor device 10.

[0127] Various configurations of the semiconductor device, the constant current source including the semiconductor device, the operational amplifier including the semiconductor device, and the display device including the operational amplifier exemplified as one embodiment of the present invention can be appropriately combined as long as they are not mutually contradictory. In addition, various configurations of the semiconductor device, the constant current source including the semiconductor device, the operational amplifier including the semiconductor device, and the display device including the operational amplifier exemplified as one embodiment of the present invention can be appropriately replaced as long as they are not mutually contradictory. Based on the semiconductor device, the constant current source including the semiconductor device, the operational amplifier including the semiconductor device, and the display device including the semiconductor device disclosed in this specification and the drawings, those in which a person skilled in the art appropriately adds, deletes, or changes the design, or adds, omits, or changes the conditions of a process are also included in the scope of the present invention as long as they include the gist of the present invention.

[0128] Even if there are other effects and advantages different from those brought about by the aspects of the embodiments disclosed in this specification, those that are clear from the description in this specification or that can be easily predicted by a person skilled in the art are naturally understood to be brought about by the present invention. [Explanation of symbols]

[0129] 10: semiconductor device, 10A: semiconductor device, 10B: semiconductor device, 11: constant current source, 12: input signal line, 14: first voltage supply wiring, 16: output signal line, 16A: output signal line, 16B: output signal line, 18: first input signal line, 20A: first transistor, 20B: second transistor, 21: operational amplifier, 21A: operational amplifier, 21B: operational amplifier, 22: second input signal line, 24: first node, 25A: third transistor, 25B: fourth transistor, 25C: fifth transistor, 26: second node, 28: second voltage supply wiring, 30: A layer, 31a: second conductive film, 31b: second conductive film, 32: semiconductor film, 32a: semiconductor film, 32aa: first end portion, 32ab: second end portion, 32b: semiconductor film, 32ba: first end portion, 32bb: second end portion, 33: gate insulating film, 34a: first conductive film, 34b: first conductive film, 35: insulating film, 38: organic film, 40: wiring layer, 45: insulating film, 48: electrode layer, 49: insulating film, 50: first alignment film, 60: liquid crystal layer, 70: second alignment film, 80: color filter layer, 90: second substrate, 100: first transistor, 100A: first transistor, 100B: second No. 1 transistor, 102: gate electrode, 104: source electrode, 106: drain electrode, 110: second transistor, 110A: second transistor, 110B: second transistor, 112: gate electrode, 114: source electrode, 116: drain electrode, 120: first substrate, 150: overcoat layer, 160: undercoat film, 200A: first transistor, 200B: first transistor, 202: first amplifier circuit, 204: second amplifier circuit, 210A: second transistor, 210B: second transistor, 212: differential amplifier section, 214: current Mirror section, 222: source ground amplifier section, 250A: first transistor, 250B: first transistor, 250C: first transistor, 260A: second transistor, 260B: second transistor, 260C: second transistor, 300: display device, 310: first drive circuit, 321: peripheral area, 322: display area, 324: seal area, 326: terminal area, 329: scanning signal line, 330: control circuit, 331: data signal line, 340: seal section, 341: connection wiring, 343: connection section, 345: common wiring, 346: capacitance wiring, 350: terminal section,360: FPC, 370: IC chip, 380: pixel, IN1: input signal, MID: intermediate electrode, OUT1: output signal, OUT2: output signal, S1: first signal, S2: second signal, VL: common voltage, VH: power supply voltage,

Claims

1. a first transistor including a first gate electrode; a second transistor having a second gate electrode electrically connected to the first gate electrode and a source electrode electrically connected to a drain electrode of the first transistor; Including, the first transistor has a first channel width and a first gate length; the second transistor has a second channel width and a second gate length; a value obtained by dividing the second channel width by the second gate length is equal to or greater than a value obtained by dividing the first channel width by the first gate length; Semiconductor device.

2. the first gate length is the same as the second gate length; The semiconductor device according to claim 1 .

3. The second channel width is N times the first channel width. The semiconductor device according to claim 2 .

4. The semiconductor device includes an active layer, the active layer includes a pattern having the first channel width and the second channel width; The semiconductor device according to claim 1 .

5. The active layer includes polysilicon. The semiconductor device according to claim 4.

6. a source electrode of the first transistor is electrically connected to a voltage supply line and receives a ground voltage from the voltage supply line; The semiconductor device according to claim 1 .

7. A semiconductor device comprising a plurality of the semiconductor devices according to any one of claims 1 to 5. Operational amplifier.

8. the plurality of semiconductor devices includes a first semiconductor device to which a first signal is input, a first amplifier circuit including the first semiconductor device, a differential amplifier section electrically connected to the first semiconductor device, and a current mirror section electrically connected to the differential amplifier section; 8. The operational amplifier of claim 7.

9. the plurality of semiconductor devices include a second semiconductor device to which the first signal is input and which is different from the first semiconductor device; a second amplifier circuit electrically connected to the first amplifier circuit, the second amplifier circuit including the second semiconductor device and a source ground amplifier unit electrically connected to the second semiconductor device; 9. The operational amplifier of claim 8.

10. A display device comprising: the operational amplifier according to claim 9; and a plurality of pixels electrically connected to the operational amplifier.

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