Semiconductor device and its control circuit

Abstract

To provide a semiconductor device capable of reducing on-resistance and switching loss, and the control circuit thereof.SOLUTION: A semiconductor device 1 includes a switching element SD and a control circuit CC. The control circuit CC is electrically connected to a first terminal DT, a second terminal ST, a control terminal GT, and a third electrode 50 of the switching element, and applies a field plate voltage between a second electrode 30 and the third electrode 50. A first diode D1 and a capacitor CB are connected in series between the first terminal DT and the second terminal ST. An anode of the first diode D1 is connected to the first terminal DT, and a cathode of the first diode D1 is connected to one terminal CBD of the capacitor CB. The other terminal CBS of the capacitor CB is connected to the second terminal ST. A drain of the first transistor Tr1 and a drain of the second transistor Tr2 are electrically connected to the third electrode 50 of the switching element SD.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments relate to a semiconductor device and its control circuit.

Background Art

[0002] Semiconductor devices such as MOS transistors are required to reduce on-resistance (conduction loss) and switching loss.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Embodiments provide a semiconductor device and its control circuit capable of reducing on-resistance and switching loss.

Means for Solving the Problems

[0005] The control circuit according to the embodiment includes a first bias terminal, a second bias terminal, an input terminal, a diode, a capacitor, a first transistor, a second transistor, and an output terminal. The second bias terminal is spaced apart from the first bias terminal, and the input terminal is spaced apart from both the first and second bias terminals. The diode has an anode connected to the first bias terminal, and the capacitor has a first terminal connected to the cathode of the diode and a second terminal connected to the second bias terminal. The first transistor includes a third terminal connected to the first terminal of the capacitor, a fourth terminal, and a first control terminal for controlling the electrical conduction between the third and fourth terminals on and off. The second transistor includes a fifth terminal connected to the fourth terminal of the first transistor, a sixth terminal connected to the second bias terminal, and a second control terminal for controlling the electrical conduction between the fifth and sixth terminals on and off. The output terminal is spaced apart from the first bias terminal, the second bias terminal, and the input terminal, and is connected to the fourth terminal of the first transistor and the fifth terminal of the second transistor. The control circuit is configured to input control signals to the first control terminal and the second control terminal based on the signal input to the input terminal, causing the first transistor and the second transistor to alternately turn on and off.

[0006] The semiconductor device according to the embodiment comprises a control circuit and a switching element connected to the control circuit. The switching element includes a first electrode connected to the first bias terminal of the control circuit, a second electrode connected to the second bias terminal of the control circuit, a third electrode connected to the output terminal of the control circuit, a control electrode connected to the input terminal of the control circuit, and a semiconductor portion electrically connected to the first electrode and the second electrode. The control electrode is configured to control the on / off electrical conduction of the semiconductor portion between the first electrode and the second electrode by the signal input to the input terminal, and the third electrode is provided between the first electrode and the second electrode and faces the semiconductor portion via an insulating film. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing a semiconductor device according to the first embodiment. [Figure 2] This is a circuit diagram showing a semiconductor device according to the first embodiment. [Figure 3] This is a circuit diagram showing the operation of the semiconductor device according to the first embodiment in the off state. [Figure 4] This is a circuit diagram showing the operation of the semiconductor device in the ON state according to the first embodiment. [Figure 5] This is a time chart showing a control method for a semiconductor device according to the first embodiment. [Figure 6] This is a time chart showing the control waveform of a semiconductor device according to the first embodiment. [Figure 7] This is a circuit diagram showing a control circuit according to the first embodiment. [Figure 8] This is a schematic cross-sectional view showing a control method for a semiconductor device according to a comparative example. [Figure 9] This graph shows the switching characteristics of the semiconductor device according to the first embodiment and comparative example. [Figure 10] This graph shows different switching characteristics of the semiconductor device according to the first embodiment and comparative example. [Figure 11]This is a circuit diagram showing a semiconductor device according to a modified example of the first embodiment. [Figure 12] This is a circuit diagram showing a control circuit according to another modified example of the first embodiment. [Figure 13] This is a time chart showing a control method for a semiconductor device according to another modified example of the first embodiment. [Figure 14] This is a schematic cross-sectional view showing a semiconductor device according to the second embodiment. [Figure 15] This is a schematic cross-sectional view showing electrode connections in a semiconductor device according to the second embodiment. [Figure 16] This is a schematic cross-sectional view showing a semiconductor device according to a modified example of the second embodiment. [Figure 17] This is a schematic diagram showing a semiconductor device according to the third embodiment. [Figure 18] This is a schematic diagram showing a semiconductor device according to the fourth embodiment. [Modes for carrying out the invention]

[0008] The embodiments will be described below with reference to the drawings. Identical parts in the drawings will be numbered the same, and detailed explanations of those parts will be omitted as appropriate, while different parts will be described. Note that the drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of sizes between parts, etc., are not necessarily the same as in reality. Furthermore, even when representing the same part, the dimensions and ratios may be depicted differently in different drawings.

[0009] Furthermore, the arrangement and configuration of each part will be explained using the X, Y, and Z axes shown in the diagram. The X, Y, and Z axes are mutually orthogonal and represent the X, Y, and Z directions, respectively. In some cases, the Z direction is described as upward and the opposite direction as downward.

[0010] (First Embodiment) FIG. 1 is a schematic diagram showing a semiconductor device 1 according to the first embodiment. The semiconductor device 1 includes, for example, a switching element SD and a control circuit CC. The switching element SD is, for example, a power MOS transistor having a trench gate structure.

[0011] As shown in FIG. 1, the switching element SD includes, for example, a semiconductor portion 10, a first electrode 20, a second electrode 30, a control electrode 40, and a third electrode 50. The semiconductor portion 10 is located between the first electrode 20 and the second electrode 30. The second electrode 30 faces the first electrode 20 across the semiconductor portion 10, for example.

[0012] The first electrode 20 is provided on the back surface of the semiconductor portion 10, for example. The first electrode 20 is, for example, a drain electrode. The second electrode 30 is provided on the surface opposite to the back surface of the semiconductor portion 10, for example. The second electrode 30 is, for example, a source electrode.

[0013] The semiconductor portion 10 includes a first semiconductor layer 11 of the first conductivity type, a second semiconductor layer 13 of the second conductivity type, a third semiconductor layer 15 of the first conductivity type, a fourth semiconductor layer 17 of the second conductivity type, and a fifth semiconductor layer 19 of the first conductivity type. Hereinafter, the first conductivity type is described as n-type and the second conductivity type is described as p-type, but the embodiment is not limited thereto.

[0014] The first semiconductor layer 11 extends between the first electrode 20 and the second electrode 30. The first semiconductor layer 11 is, for example, an n-type drift layer. The second semiconductor layer 13 is provided between the first semiconductor layer 11 and the second electrode 30. The second semiconductor layer 13 is, for example, a p-type body layer.

[0015] The third semiconductor layer 15 is provided between the second semiconductor layer 13 and the second electrode 30. The third semiconductor layer 15 is, for example, an n-type source layer. The third semiconductor layer 15 is in contact with and electrically connected to the second electrode 30, for example.

[0016] The fourth semiconductor layer 17 is provided between the second semiconductor layer 13 and the second electrode 30, and at least a portion of it is located within the second semiconductor layer 13. The fourth semiconductor layer 17 is, for example, a p-type contact layer. The fourth semiconductor layer 17 contains a second conductivity type impurity at a higher concentration than the second conductivity type impurity in the second semiconductor layer 13. The second electrode 30 includes, for example, a contact portion 30c that is in contact with and electrically connected to the fourth semiconductor layer 17. The second electrode 30 is electrically connected to the second semiconductor layer 13 via the fourth semiconductor layer 17.

[0017] The fifth semiconductor layer 19 is provided between the first semiconductor layer 11 and the first electrode 20. The fifth semiconductor layer 19 is, for example, an n-type buffer layer. The fifth semiconductor layer 19 contains n-type impurities at a higher concentration than the n-type impurities in the first semiconductor layer 11. The first electrode 20 is, for example, in contact with and electrically connected to the fifth semiconductor layer 19.

[0018] The semiconductor portion 10 has a trench TG provided on its surface side. The control electrode 40 and the third electrode 50 are provided inside the trench TG. The control electrode 40 is located between the second electrode 30 and the third electrode 50. The third electrode 50 is located between the first electrode 20 and the control electrode 40.

[0019] The control electrode 40 is, for example, a gate electrode. The control electrode 40 is positioned to face the second semiconductor layer 13 via a first insulating film 43. The first insulating film 43 is, for example, a gate insulating film. The control electrode 40 is positioned to face the first semiconductor layer 11 via the first insulating film 43. The control electrode 40 also faces the third semiconductor layer 15 via the first insulating film 43. In other words, the first insulating film 43 electrically insulates the control electrode 40 from the semiconductor portion 10.

[0020] Furthermore, a second insulating film 45 is provided between the second electrode 30 and the control electrode 40. The second insulating film 45 is, for example, an interlayer insulating film. The second insulating film 45 electrically insulates the control electrode 40 from the second electrode 30.

[0021] The third electrode 50 is, for example, a field plate. The third electrode 50 is located in the first semiconductor layer 11. 5 0 is provided facing the first semiconductor layer 11 via a third insulating film 53. The third insulating film 53 is, for example, a field plate insulating film (FP insulating film). The third insulating film 53 electrically insulates the third electrode 50 from the first semiconductor layer 11. A fourth insulating film 55 is provided between the control electrode 40 and the third electrode 50. The fourth insulating film 55 electrically insulates the control electrode 40 from the third electrode 50.

[0022] As shown in Figure 1, the semiconductor device 1 further comprises a first terminal DT, a second terminal ST, and a control terminal GT. The first terminal DT, the second terminal ST, and the control terminal GT are connected to the switching element SD and the control circuit CC.

[0023] The first terminal DT is, for example, the drain terminal. The first terminal DT is connected to the first electrode 20 of the switching element SD. The second terminal ST is, for example, the source terminal. The second terminal ST is connected to the second electrode 30 of the switching element SD. The control terminal GT is, for example, the gate terminal. The control terminal GT is electrically connected to the control electrode 40 of the switching element SD, for example. The control terminal GT is electrically connected to the control electrode 40 via, for example, a gate resistor Rg. The gate resistor Rg is, for example, the internal resistance of the control electrode 40.

[0024] The control circuit CC is electrically connected, for example, to the first terminal DT, the second terminal ST, the control terminal GT, and the third electrode 50 of the switching element SD. The control circuit CC applies a field plate voltage VFP between the second electrode 30 and the third electrode 50. Canada It is configured to do so.

[0025] The control circuit CC includes, for example, a first transistor Tr1, a second transistor Tr2, a third transistor Tr3, a first diode D1, a second diode D2, and a capacitor CB. The first transistor Tr1 is, for example, a PMOS transistor. The second transistor Tr2 and the third transistor Tr3 are, for example, NMOS transistors.

[0026] The first diode D1 and capacitor CB are connected in series between the first terminal DT and the second terminal ST. The anode of the first diode D1 is connected to the first terminal DT, and the cathode of the first diode D1 is connected to one terminal CBD of capacitor CB. The other terminal CBS of capacitor CB is connected to the second terminal ST.

[0027] The first transistor Tr1 and the second transistor Tr2 are connected in series, with the drain of the first transistor Tr1 connected to the drain of the second transistor Tr2. The source of the first transistor Tr1 is connected to the cathode of the first diode D1 and terminal CBD of capacitor CB. The source of the second transistor Tr2 is connected to terminal ST.

[0028] The second diode D2 and the third transistor Tr3 are connected in series between the first terminal DT and the second terminal ST. The anode of the second diode D2 is connected to the first terminal DT, and the cathode of the second diode D1 is connected to the drain of the third transistor Tr3. The source of the third transistor is connected to the second terminal ST. The gates of the first transistor Tr1 and the second transistor Tr2 are connected to the cathode of the second diode D2 and the drain of the third transistor Tr3.

[0029] The gate of the third transistor Tr3 is connected to the control terminal GT. Additionally, the drains of the first transistor Tr1 and the second transistor Tr2 are electrically connected to the third electrode 50 of the switching element SD.

[0030] Figure 2 is a circuit diagram showing a semiconductor device 1 according to the first embodiment. As shown in Figure 2, the switching element SD and the control circuit CC are connected to the first terminal DT and the second terminal ST, and a mark is made between the first terminal DT and the second terminal ST. Canada It is biased by the applied voltage Vds (see Figure 5).

[0031] The drain D of the switching element SD is connected to the first terminal DT, and the source S of the switching element SD is connected to the second terminal ST. Furthermore, the gate G of the switching element SD is connected to the control terminal GT.

[0032] The switching element SD is controlled on and off by a control signal Vg (see Figure 5) input to the gate G. The control signal Vg is input to the control terminal GT. The control terminal GT is electrically connected to the gate G of the switching element SD. control The signal Vg is, for example, connected to the control terminal GT and the switch. ッ It is supplied between the source S of the ching element SD.

[0033] The control signal Vg is also input to the gate of the third transistor Tr3 via the control terminal GT. The third transistor Tr3 is switched on and off by the control signal Vg. Furthermore, the first transistor Tr1 and the second transistor Tr2 are switched on and off by the potential on the drain side of the third transistor Tr3.

[0034] For example, when the third transistor Tr3 is in the off state and its drain is at a high potential, the first transistor Tr1 is in the off state and the second transistor Tr2 is in the on state. When the third transistor Tr3 is turned on, its drain becomes low, the first transistor Tr1 transitions from the off state to the on state, and the second transistor Tr2 transitions from the on state to the off state.

[0035] Figure 3 is a circuit diagram showing the operation of the semiconductor device 1 in the off state according to the first embodiment. At this time, the control signal Vg (see Figure 5) input to the control terminal GT is "Low". The control signal Vg is applied to the gate G of the switching element SD via an external gate resistor Rge, and the switching element SD is turned off. A voltage Vdd is applied between the first terminal DT and the second terminal ST via a load resistor RL. A drain voltage Vd-off (see Figure 5) is applied between the first terminal DT and the second terminal ST.

[0036] When the control signal Vg is "Low," the third transistor Tr3 of the control circuit CC (see Figure 2) is in the off state, and the potential of the drain side of the third transistor Tr3 is "High." At this time, the first transistor Tr1 is in the off state, and the second transistor Tr2 is in the on state. Capacitor CB is charged by the drain voltage Vd-off. The field plate FP (third electrode 50) of the switching element SD becomes at the same potential as the second terminal ST via the on-state second transistor Tr2. That is, the potential difference VFP between the field plate FP and source S of the switching element SD is 0V (see Figure 5).

[0037] Figure 4 is a circuit diagram showing the operation of the semiconductor device in the ON state according to the first embodiment. At this time, the control signal Vg (see Figure 5) input to the control terminal GT is "High". The gate G of the switching element SD becomes "High", and the switching element SD is turned ON. A drain current Id flows between the first terminal DT and the second terminal ST, and the voltage between the first terminal DT and the second terminal ST drops to the ON voltage Vd-on level (see Figure 5).

[0038] When the control signal Vg is "High," the third transistor Tr3 (see Figure 2) of the control circuit CC is turned ON, and the potential of the drain side of the third transistor Tr3 becomes "Low." At this time, the first transistor Tr1 is turned ON, and the second transistor Tr2 is turned OFF. As a result, the electrical connection between the field plate FP and the second terminal ST of the switching element SD is disconnected, and the terminal CBD of the capacitor CB and the field plate FP are electrically connected via the ON first transistor Tr1. This causes the charge from the capacitor CB to move to the field plate FP, and the field plate FP becomes at the same potential as the terminal CBD of the capacitor CB. That is, the voltage Vc-on between both terminals of the capacitor CB is marked as Vfp-on between the field plate FP and the source S of the switching element SD. Canada (See Figure 5).

[0039] Figure 5 is a time chart showing the control method of the semiconductor device 1 according to the first embodiment. Figure 5 shows the gate input signal Vg-in, the gate output signal Vg-out, the control signal Vg1 of the first transistor Tr1, the control signal Vg2 of the second transistor Tr2, the source-drain voltage Vds, the terminal voltage VCB of the capacitor CB, and the field plate voltage VFP.

[0040] As shown in Figure 5, the gate input signal Vg-in input to the control terminal GT rises from Low to High, for example, at time T1. The gate output signal Vg is output from the control circuit CC. - out is the same as the gate input signal Vg-in, and is a mark between the gate G and source S of the switching element SD. Canada This causes the switching element SD to transition from the off state to the on state (hereinafter referred to as turn-on).

[0041] The gate input signal Vg-in is also input to the gate of the third transistor Tr3, causing the third transistor Tr3 to turn on at time T1. As a result, the potential of the drain side of the third transistor Tr3 changes from High to Low, and the control signals Vg1 of the first transistor Tr1 and Vg2 of the second transistor Tr2 also change from High to Low. Consequently, the first transistor Tr1 turns on, and the second transistor Tr2 transitions from the ON state to the OFF state (hereinafter referred to as Turn Off).

[0042] The source-drain voltage Vds decreases from the off voltage Vd-off to the on voltage Vd-on at time T1. Since the on voltage Vd-on is lower than the voltage Vc-off across capacitor CB when the switching element SD is in the off state, charging of capacitor CB stops at time T1.

[0043] Capacitor CB is electrically connected to the field plate FP of the switching element SD via the first transistor Tr1, which is in the ON state. On the other hand, the electrical connection between the field plate FP and the source S is disconnected when the second transistor Tr2 is turned off. As a result, the charge of capacitor CB moves to the field plate FP via the first transistor Tr1. Consequently, the terminal voltage of capacitor CB drops to the voltage Vc-on, which is the voltage when the switching element SD is in the ON state.

[0044] The parasitic capacitance of the field plate FP in the switching element SD is charged by the charge moving from capacitor CB until the potential difference between the field plate FP and the source S becomes equal to the terminal voltage VCB of capacitor CB. As a result, the field plate voltage VFP rises from 0V to Vfp-on at time T1. Vfp-on is equal to the voltage Vc-on of capacitor CB.

[0045] Furthermore, the gate input signal Vg-in changes from High to Low at time T2. The gate output signal Vg-out also changes from High to Low, and the switching element SD is turned off. The third transistor Tr3 is also turned off. As a result, the potential of the drain side of the third transistor Tr3 changes from Low to High, and the control signals Vg1 of the first transistor Tr1 and Vg2 of the second transistor Tr2 also change from Low to High. Consequently, the first transistor Tr1 is turned off, and the second transistor Tr2 is turned on.

[0046] At time T2, the source-drain voltage Vds rises from the on-voltage Vd-on to the off-voltage Vd-off, and charging of capacitor CB begins. The terminal voltage VCB of capacitor CB rises from Vc-on to Vc-off. The electrical connection between capacitor CB and the field plate FP of the switching element SD is interrupted by the turned-off first transistor Tr1, and the field plate FP and source S are electrically connected via the turned-on second transistor Tr2. As a result, the field plate voltage VFP between the field plate FP and source S becomes 0V.

[0047] Next, the gate input signal Vg-in changes from Low to High at time T3, and the switching element SD and the third transistor Tr3 are turned on. Consequently, the first transistor Tr1 is turned on and the second transistor Tr2 is turned off. As a result, the field plate voltage VFP between the field plate FP and the source S rises from 0V to Vfp-on.

[0048] Figure 6 is a time chart showing the control waveform of the semiconductor device 1 according to the first embodiment. The vertical axis represents voltage, and the horizontal axis represents time. Figure 6 shows the control signal Vg, the source-drain voltage Vds, and the terminal voltage VCB of the capacitor CB.

[0049] As shown in Figure 6, the control signal Vg rises at time T1 and falls at time T2. When the control signal Vg exceeds the gate threshold voltage of the switching element SD, the switching element SD is turned on, and the source-drain voltage Vds drops from the off voltage Vd-off to, for example, an on voltage Vd-on close to 0V. Correspondingly, the terminal voltage VCB of the capacitor CB drops to the level of Vc-on (=Vfp-on). At this time, a mark is formed between the field plate FP and the source S. Canada The applied voltage Vfp-on is preferably greater than the "High" level of the control signal Vg. To apply a voltage Vfp-on of a sufficient level between the field plate FP and the source S, for example, the capacitance value of capacitor CB is preferably greater than the parasitic capacitance between the field plate FP and the drain D.

[0050] When the control signal Vg drops below the gate threshold voltage of the switching element SD, the switching element SD is turned off, and the source-drain voltage Vds rises from the on voltage Vd-on to the off voltage Vd-off. This initiates charging of the capacitor CB, and the terminal voltage VCB rises to Vc-off.

[0051] Figure 7 is a circuit diagram showing a control circuit CC according to the first embodiment. The control circuit CC includes, for example, bias terminals TB1 and TB2, an input terminal TI, and output terminals TO1 and TO2. The terminals are spaced apart from each other.

[0052] The bias terminal TB1 is connected to, for example, the first terminal DT, and the bias terminal TB2 is connected to, for example, the second terminal ST. The input terminal TI corresponds to the control terminal GT. The output terminal TO1 is connected to the drain of the first transistor Tr1 and the second transistor Tr2 It is connected to the drain. The output terminal TO2 is connected to the input terminal TI, and the signal input to the input terminal TI is output directly from the output terminal TO2.

[0053] The input terminal TI is the third transistor. Tr3 It is also connected to the gate of the third transistor. Tr3 It is controlled on / off by a signal input to the input terminal TI.

[0054] When the switching element SD to be driven is in the off state, the first transistor Tr1 of the control circuit CC is in the off state, and the second transistor Tr2 is in the on state. Therefore, a voltage approximately equivalent to the voltage between the drain and source of the switching element SD is applied across the drain and source of the first transistor Tr1. Consequently, it is preferable that the withstand voltage between the drain and source of the first transistor Tr1 is greater than or equal to the withstand voltage between the drain and source of the switching element SD.

[0055] Furthermore, when the switching element SD is in the off state, the third transistor Tr3 is also in the off state. Therefore, the third transistor Tr3 A voltage approximately equivalent to the voltage between the drain and source of the switching element SD is applied between the drain and source of the third transistor Tr3. Therefore, it is preferable that the withstand voltage between the drain and source of the third transistor Tr3 is greater than or equal to the withstand voltage between the drain and source of the switching element SD.

[0056] The input capacitance Ciss, output capacitance Coss, and feedback capacitance Crss of the first to third transistors Tr1, Tr2, and Tr3 are preferably smaller than the parasitic capacitances of the switching element SD in order to reduce gate drive losses and switching losses. In other words, it is desirable that the gate drive losses and switching losses in the control circuit CC be negligible when compared with the switching losses of the switching element SD.

[0057] Figures 8(a) and (b) are schematic cross-sectional views showing a control method for semiconductor device 1 according to a comparative example. Figures 8(a) and (b) show a control method for the third electrode 50 of the switching element SD.

[0058] In the example shown in Figure 8(a), the third electrode 50 is electrically connected to the second electrode 30 so that it is at the same potential as the second electrode 30. In other words, the field plate FP is connected to the source S.

[0059] In the example shown in Figure 8(b), the third electrode 50 is connected to the control terminal GT. That is, the field plate FP is at the same potential as the gate G. For example, when a "High" level control signal Vg is applied to the control electrode 40 from the control terminal GT and the switching element SD is turned on, an n-type storage layer AL is induced in the first semiconductor layer 11 facing the third electrode 50 (field plate FP). This reduces the electrical resistance of the first semiconductor layer 11 between adjacent trenches TG, thereby reducing the on-resistance of the switching element SD.

[0060] Figures 9(a) to 9(c) are graphs showing the switching characteristics of the semiconductor device 1 according to the first embodiment and comparative example. Figures 9(a) to 9(c) show the voltage waveform and current waveform when the semiconductor device 1 is turned on. The horizontal axis represents time.

[0061] Figure 9(a) shows the turn-on characteristics when the field plate FP is connected to the source S. At time T1, when the control signal Vg rises and exceeds the gate threshold voltage of the switching element SD, the drain current Id begins to flow and rises to the level of the on current Id-on. Meanwhile, the source-drain voltage Vds decreases from the off voltage Vd-off to the on voltage Vd-on. During this time, the voltage VFP between the field plate FP and the source S is 0V.

[0062] Figure 9(b) shows the turn-on characteristics when the field plate FP is connected to the gate G. At time T1, when the control signal Vg rises and exceeds the gate threshold voltage of the switching element SD, the drain current Id begins to flow. Since the control signal Vg is also supplied to the field plate FP, an n-type storage layer AL is induced in the first semiconductor layer 11 facing the field plate FP, thereby reducing the on-resistance. However, the parasitic capacitance between the gate and drain increases, delaying the rise of the control signal Vg. As a result, the time it takes for the drain current Id to reach the Id-on level and the time it takes for the source-drain voltage Vds to decrease to Vd-on are delayed, increasing the turn-on time ΔTon. In other words, while it is possible to reduce the on-resistance when the field plate FP is connected to the gate G, the turn-on time ΔTon becomes longer.

[0063] Figure 9(c) shows the turn-on characteristics in the control method according to the embodiment. At time T1, when the control signal Vg rises and exceeds the gate threshold voltage of the switching element SD, the drain current Id begins to flow. Meanwhile, the source-drain voltage Vds decreases from the off voltage Vd-off to the on voltage Vd-on. During this time, the voltage VFP between the field plate FP and the source S rises from 0V to Vfp-on. Vfp-on is higher than the control signal Vg, and the field plate FP is biased to a potential higher than the control signal Vg. As a result, a higher density n-type storage layer is induced in the first semiconductor layer 11, which can further reduce the on-resistance.

[0064] In this case, the terminal voltage VCB of capacitor CB is applied to the field plate FP, and the capacitance between the field plate FP and the drain is isolated from the gate-drain capacitance. This prevents the parasitic capacitance between the gate and drain from becoming large. As a result, the turn-on time ΔTon can be shortened compared to when the field plate FP is connected to the gate G. The turn-on time ΔTon in the control method according to this embodiment is equivalent to the turn-on time ΔTon when the field plate FP is connected to the source S.

[0065] Figures 10(a) to 10(c) are graphs showing different switching characteristics of the semiconductor device 1 according to the first embodiment and comparative example. Figures 10(a) to 10(c) show the voltage waveform and current waveform when the semiconductor device 1 is turned off. The horizontal axis represents time.

[0066] Figure 10(a) shows the turn-off characteristics when the field plate FP is connected to the source S. At time T2, as the control signal Vg falls and approaches the gate threshold voltage of the switching element SD, the drain current Id begins to decrease and drops to 0 level. Meanwhile, the source-drain voltage Vds rises from the on voltage Vd-on to the off voltage Vd-off. During this time, the voltage VFP between the field plate FP and the source S is 0V.

[0067] Figure 10(b) shows the turn-off characteristics when the field plate FP is connected to the gate G. At time T2, as the control signal Vg falls and approaches the gate threshold voltage of the switching element SD, the drain current Id begins to decrease and falls to 0 level. The n-type storage layer AL induced in the first semiconductor layer 11 disappears as the control signal Vg decreases. In this case as well, the falling of the control signal Vg is delayed due to the large parasitic capacitance between the gate and drain. As a result, the time it takes for the drain current Id to reach 0 level from Id-on, and the time it takes for the source-drain voltage Vds to rise from Vd-on to Vd-off are delayed, and the turn-off time ΔToff becomes longer.

[0068] Figure 10(c) shows the turn-on characteristics in the control method according to the embodiment. At time T2, as the control signal Vg falls and approaches the gate threshold voltage of the switching element SD, the drain current Id begins to decrease. The source-drain voltage Vds also rises from the on voltage Vd-on to the off voltage Vd-off. During this time, the voltage VFP decreases from Vfp-on to 0V. As a result, the n-type storage layer induced in the first semiconductor layer 11 disappears.

[0069] In the control method according to this embodiment, when the switching element SD is turned off, the electrical connection between the field plate FP and the capacitor CB is interrupted, and the field plate FP is connected to the source S. As a result, charge is discharged from the field plate FP to the source S, and the field plate voltage VFP drops from Vfp-on to 0V. Therefore, the discharge of charge from the field plate FP does not affect the turn-off of the switching element SD, and the turn-off time ΔToff can be shortened.

[0070] Thus, in semiconductor device 1, a so-called bootstrap circuit including capacitor CB is provided in the control circuit CC to control the voltage VFP between the field plate FP and the source S. Capacitor CB is charged from the drain side when the switching element SD is turned off, and charges the field plate FP when it is turned on. That is, since the potential of the field plate FP is controlled independently of the gate electrode, it is possible to shorten the turn-on time and turn-off time, and furthermore, gate driver losses can be avoided. Also, by biasing the field plate FP to a potential higher than the gate electrode potential, it is possible to increase the density of the n-type storage layer AL and further reduce the on-resistance.

[0071] Figure 11 is a circuit diagram showing a modified semiconductor device 2 according to the first embodiment. The semiconductor device 2 includes a switching element SD and a control circuit CC2.

[0072] In this example, the control circuit CC2 has a configuration in which the second diode D2 (see Figure 2) between the first terminal DT and the third transistor Tr3 is replaced with a resistor R1. That is, if the switching speed of the first to third transistors Tr1, Tr2, and Tr3 in the control circuit CC2 is sufficiently faster than the switching speed of the switching element SD, the circuit can be simplified and costs reduced by using a resistor R1 instead of the second diode D2.

[0073] Figure 12 is a circuit diagram showing a control circuit CC3 according to another modification of the first embodiment. In this example, the gate of the first transistor Tr1 and the third transistor Tr 3 Between the drain and the gate of the second transistor Tr2 and the third transistor Tr 3 A delay circuit DE is provided between the drain and the other component.

[0074] Figure 13 is a time chart showing a control method for semiconductor device 1 according to another modification of the first embodiment. Figure 13 shows the control signal Vg, source-drain voltage Vds, drain current Id, and voltage VFP between the field plate FP and source S.

[0075] As shown in Figure 13, the control signal Vg input to the control terminal GT rises from Low to High, for example, at time T1. The control signal Vg is applied between the gate G and source S of the switching element SD. Canada This occurs (see Figure 2). As a result, the switching element SD turns on, and the drain current Id increases from 0 level to on current Id-on. Consequently, the source-drain voltage Vds decreases from off voltage Vd-off to on voltage Vd-on.

[0076] Furthermore, at time T2, which is later than time T1, the control signal Vg is reduced from High to Low. As a result, the switching element SD turns off, and the drain current Id decreases from the on current Id-on to level 0. Consequently, the source-drain voltage Vds rises from the on voltage Vd-on to the off voltage Vd-off.

[0077] On the other hand, the voltage VFP between the field plate FP and the source S is controlled to rise from 0 level to Vfp-on at time T3, which is after time T1 and before time T2. This rise control is performed in the control circuit CC3. That is, the delay between time T1 and time T3 is controlled by the delay circuit DE.

[0078] For example, if the drain-source voltage remains at the off voltage Vd-off, and the first transistor Tr1 turns on due to noise from the control signal Vg, then Vfp-on is marked on the field plate FP. Canada This can lead to dielectric breakdown between the field plate FP and the gate G. Therefore, it is preferable to raise the field plate voltage VFP to Vfp-on after the timing of turning on the switching element SD. For example, a Schmitt trigger circuit can be used as the delay circuit DE that delays the rise of the field plate voltage VFP.

[0079] (Second Embodiment) Figure 14 is a schematic cross-sectional view showing a semiconductor device 3 according to the second embodiment. The semiconductor device 3 has a monolithic integrated structure of a switching element SD and a capacitor CB. The switching element SD has the same structure as the MOS transistor shown in Figure 1.

[0080] As shown in Figure 14, the semiconductor portion 10 includes a switching region SDR and a capacitor region CBR between the first electrode 20 and the second electrode 30. The switching region SDR and the capacitor region CBR are aligned in a direction along the back surface of the semiconductor portion 10. The second electrode 30 is provided on the surface of the semiconductor portion 10 in the capacitor region CBR, for example, via an interlayer insulating film 45.

[0081] A first trench TG1 is provided in the switching region SDR, and a second trench TG2 is provided in the capacitor region CBR. The first trench TG1 includes a control electrode 40 and a third electrode 50. The second trench TG2 includes a fourth electrode 60. The fourth electrode 60 faces the semiconductor portion 10 via a dielectric film 63. The fourth electrode 60 is electrically insulated from the semiconductor portion 10 by the dielectric film 63. The dielectric film 63 is an insulating film having a predetermined dielectric constant.

[0082] In the capacitor region CBR, the semiconductor portion 10 includes, for example, a first semiconductor layer 11, a fifth semiconductor layer 19, and a sixth semiconductor layer 21 of the second conductivity type. The first semiconductor layer 11 extends between the first electrode 20 and the second electrode 30. The fifth semiconductor layer 19 is provided between the first electrode 20 and the first semiconductor layer 11. The sixth semiconductor layer 21 is provided within the first semiconductor layer 11. The first semiconductor layer 11 extends between the sixth semiconductor layer 21 and the second electrode 30. Furthermore, a portion of the first semiconductor layer 11 is interposed between the fifth semiconductor layer 19 and the sixth semiconductor layer 21.

[0083] The second trench TG2 is located from the surface of the semiconductor part 10 on the side of the second electrode 30. 1 It extends within the semiconductor layer 11. The bottom of the second trench TG2 is located within the sixth semiconductor layer 21. The fourth electrode 60 is provided between the first electrode 20 and the second electrode 30 and faces the sixth semiconductor layer 21 via the dielectric film 63. The fourth electrode 60 is also connected to the second electrode 30 on the opening side of the second trench TG2. The second electrode 30 is connected to the fourth electrode through a contact hole provided in the interlayer insulating film 45. 60 It is electrically connected to it.

[0084] The sixth semiconductor layer 21 is electrically connected to the first electrode 20, for example. In other words, the sixth semiconductor layer 21 is electrically connected to the first electrode 20 without the intervening PN junction.

[0085] In this example, the capacitor CB is provided, for example, between the first semiconductor layer 11 and the fourth electrode 60. The dielectric film 63 is provided so that the capacitor CB has a predetermined capacitance value. Furthermore, the first semiconductor layer 11 and the sixth semiconductor layer 21 constitute the first diode D1 (see Figure 2). The sixth semiconductor layer 21 is the anode of the first diode D1 and is electrically connected to the first electrode 20. The first semiconductor layer 11 serves as both the cathode of the first diode D1 and the terminal CBD of the capacitor CB (see Figure 2).

[0086] The first electrode 20 is the drain electrode of the switching element SD and is connected to the anode of the first diode D1 (see Figure 2). The second electrode 30 is the source electrode of the switching element SD and also serves as the terminal CBS of the capacitor CB (see Figure 2).

[0087] The semiconductor device 3 further includes a diode terminal TD1. Diode terminal TD1 is the cathode terminal of the first diode D1 and is electrically connected to the first semiconductor layer 11. Diode terminal TD1 is connected, for example, to the source of the first transistor Tr1 (see Figure 2).

[0088] Figures 15(a) and (b) are schematic cross-sectional views showing electrode connections in the semiconductor device 3 according to the second embodiment. Figure 15(a) illustrates the connection structure between the first electrode 20 and the sixth semiconductor layer 21. Figure 15(b) illustrates the connection structure between the diode terminal TD1 and the first semiconductor layer 11.

[0089] As shown in Figure 15(a), the first electrode 20 has a contact portion 20p that extends into the contact trench BT provided on the back side of the semiconductor portion 10. BT It is provided to have a depth that penetrates the fifth semiconductor layer 19 and the first semiconductor layer 11 and reaches the sixth semiconductor layer 21. 1 electrode 2 0 is connected to the sixth semiconductor layer 21 in the contact portion 20p that extends into the interior of the contact trench BT.

[0090] As shown in Figure 15(b), the diode terminal TD1 is provided on the first semiconductor layer 11 via a second insulating film 45. The diode terminal TD1 is provided on the second insulating film 45 spaced apart from the second electrode 30. The diode terminal TD1 has a portion that extends into a contact hole 45ch provided in the second insulating film 45. That is, the diode terminal TD1 is connected to the first semiconductor layer 11 through the contact hole 45ch.

[0091] Figure 16 is a schematic cross-sectional view showing a modified semiconductor device 4 according to the second embodiment. In this example as well, the semiconductor device 4 has a monolithic integrated structure of a switching element SD and a capacitor CB. The switching element SD has the same structure as the MOS transistor shown in Figure 1.

[0092] The semiconductor device 4 includes a first electrode 20, a second electrode 30, a control electrode 40, a third electrode 50, a fourth electrode 60, and a fifth electrode 70. The semiconductor portion 10 is located between the first electrode 20 and the second electrode 30, and between the first electrode 20 and the fifth electrode 70, and includes a switching region SDR and a capacitor region CBR. The fifth electrode 70 is provided on the interlayer insulating film 45 on the surface side of the capacitor region CBR. The second electrode 30 and the fifth electrode 70 are provided spaced apart from each other on the interlayer insulating film 45.

[0093] The control electrode 40 and the third electrode 50 are located inside the first trench TG1 in the switching region SDR. The fourth electrode 60 is located inside the second trench TG2 in the capacitor region CBR. The fourth electrode 60 is connected to the second electrode 30, for example, through a contact hole provided in the interlayer insulating film 45.

[0094] The semiconductor section 10 includes a first semiconductor layer 11, a fifth semiconductor layer 19, a sixth semiconductor layer 21, a seventh semiconductor layer 22 of the second conductivity type, and an eighth semiconductor layer 23 of the first conductivity type in the capacitor region CBR. The fifth semiconductor layer 19 is provided between the first semiconductor layer 11 and the first electrode 20.

[0095] The sixth semiconductor layer 21 is provided in the first semiconductor layer 11 between the first electrode 20 and the second electrode 30, and between the first electrode 20 and the fifth electrode 70. The first semiconductor layer 11 extends between the sixth semiconductor layer 21 and the second electrode 30. In addition, a portion of the first semiconductor layer 11 is interposed between the fifth semiconductor layer 19 and the sixth semiconductor layer 21.

[0096] The sixth semiconductor layer 21 is drawn out to the surface side of the semiconductor portion 10 between the first electrode 20 and the fifth electrode 70. On the surface side of the semiconductor portion 10, the sixth semiconductor layer 21 is electrically connected to the fifth electrode 70 via the seventh semiconductor layer 22. The seventh semiconductor layer 22 is provided between the sixth semiconductor layer 21 and the fifth electrode 70 and contains a second conductivity type impurity at a higher concentration than the second conductivity type impurity in the sixth semiconductor layer 21. The fifth electrode 70 is connected to the seventh semiconductor layer 22 through a contact hole provided in the interlayer insulating film 45.

[0097] The eighth semiconductor layer 23 is provided between the first semiconductor layer 11 and the fifth electrode 70. The eighth semiconductor layer 23 is provided, for example, in the first semiconductor layer 11 on the surface side of the semiconductor portion 10. The eighth semiconductor layer 23 contains a first conductivity type impurity at a higher concentration than the first conductivity type impurity in the first semiconductor layer 11. The fifth electrode 70 is connected to the eighth semiconductor layer 23 through another contact hole provided in the interlayer insulating film 45. The fifth electrode 70 is electrically connected to the first semiconductor layer 11 via the eighth semiconductor layer 23.

[0098] In this example as well, the first electrode 20 is the drain electrode of the switching element SD. The second electrode 30 is the source electrode of the switching element SD and also serves as the source terminal CBS of the capacitor CB.

[0099] The first semiconductor layer 11 and the sixth semiconductor layer 21 constitute the first diode D1 (see Figure 2). The fifth electrode 70 is the anode electrode of the first diode D1 and is electrically connected to the first electrode 20 via the eighth semiconductor layer 23, the first semiconductor layer 11, and the fifth semiconductor layer 19.

[0100] Capacitor CB is provided between the first semiconductor layer 11 and the fourth electrode 60. The first semiconductor layer 11 serves as both the cathode of the first diode D1 and the terminal CBD of capacitor CB (see Figure 2). Diode terminal TD1 is electrically connected to the first semiconductor layer 11. Diode terminal TD1 is the cathode terminal of the first diode D1 and is connected, for example, to the source of the first transistor Tr1.

[0101] (Third embodiment) Figure 17 is a schematic diagram showing a semiconductor device 5 according to the third embodiment. The semiconductor device 5 includes a switching element SD2 and a control circuit CC. The switching element SD2 is, for example, a power MOS transistor having a planar gate structure. The semiconductor device 5 is a hybrid device comprising, for example, a switching element SD2 and a control chip including a control circuit CC.

[0102] The switching element SD2 includes, for example, a semiconductor portion 10, a third electrode (hereinafter referred to as gate electrode 40), and a fourth electrode (hereinafter referred to as field plate 50). In the following description, the source electrode will be referred to as source S, the drain electrode as drain D, the gate terminal as gate G, and the field plate terminal as FP terminal.

[0103] As shown in Figure 17, the semiconductor portion 10 includes an n-type drift layer 11, a p-type body layer 13, an n-type source layer 15, a p-type contact layer 17, an n-type buffer layer 19, a p-type well 25, and an n-type contact layer 26.

[0104] The p-type well 25 contains p-type impurities at a lower concentration than the p-type impurities in the p-type body layer 13. The n-type drift layer 11 and the p-type body layer 13 are aligned on the p-type well 25. The n-type drift layer 11 and the p-type body layer 13 are aligned in a direction along the surface of the semiconductor portion 10, for example, in the X direction. The n-type buffer layer 19 is partially provided on the n-type drift layer 11. The n-type contact layer 26 is provided on the n-type buffer layer 19. The n-type contact layer 26 contains n-type impurities at a higher concentration than the n-type impurities in the n-type buffer layer 19.

[0105] The n-type source layer 15 and the p-type contact layer 17 are aligned, for example, in the X direction on the p-type body layer 13. The n-type source layer 15 is located, for example, between the n-type drift layer 11 and the p-type contact layer 17. The p-type body layer 13 extends between the n-type drift layer 11 and the n-type source layer 15.

[0106] The thickness of the n-type drift layer 11 in the Z direction is, for example, greater than the thickness of the p-type body layer 13 in the Z direction. On the surface side of the semiconductor portion 10, a Shallow Trench Isolation (STI) is partially provided on the n-type drift layer 11. The STI is provided between the portion of the n-type drift layer 11 facing the p-type body layer 13 and the n-type contact layer 26.

[0107] The gate electrode 40 is provided on the surface of the semiconductor portion 10 via a gate insulating film 43. The gate electrode 40 faces the p-type body layer 13 between the n-type drift layer 11 and the n-type source layer 15 via the gate insulating film 43. The field plate 50 is provided on the surface of the semiconductor portion 10 via an FP insulating film 53. The field plate 50 faces the n-type drift layer 11 via the FP insulating film 53. The gate electrode 40 and the field plate 50 are provided adjacent to each other and spaced apart from each other. The field plate 50 also extends on the STI.

[0108] The switching element SD2 further includes an interlayer insulating film 45. The interlayer insulating film 45 is provided on the surface side of the semiconductor portion 10 and covers the gate electrode 40 and the field plate 50. The source S, drain D, gate G and FP terminals are provided on the interlayer insulating film 45.

[0109] The drain D is connected to the n-type contact layer 26 through a contact hole provided in the interlayer insulating film 45. The source S is connected to the n-type source layer 15 and the p-type contact layer 17 through another contact hole provided in the interlayer insulating film 45. The gate G and FP terminals are connected to the gate electrode 40 and the field plate 50, respectively, through other contact holes provided in the interlayer insulating film 45.

[0110] Drain D is connected to the first terminal DT. Source S is connected to the second terminal ST. Gate G is connected to the control terminal GT.

[0111] The control circuit CC includes a capacitor CB, a first transistor Tr1, a second transistor Tr2, and a third transistor Tr3, and has the same configuration as the control circuit CC shown in Figure 2. The FP terminal of the switching element SD2 is connected to the drains of the first transistor Tr1 and the second transistor Tr2. The control terminal GT is also connected to the gate of the third transistor Tr3.

[0112] (Fourth Embodiment) Figure 18 is a schematic diagram showing a semiconductor device 6 according to the fourth embodiment. The semiconductor device 6 comprises a monolithically integrated switching element SD2 (see Figure 17), a first transistor Tr1, a second transistor Tr2, a third transistor Tr3, a first diode D1, a second diode D2, and a capacitor CB. Each element has an SOI (silicon on insulator) structure, for example, provided on a semiconductor substrate SS via an insulating layer 65. The first to third transistors Tr1 to Tr3 are, for example, MOS transistors having a planar gate structure.

[0113] The drain D of switching element SD2 is connected to the first terminal DT. Additionally, the anode A of the first diode D1 and the anode of the second diode D2 are also connected to the first terminal DT.

[0114] The sources S of the switching element SD2, the second transistor Tr2, and the third transistor Tr3 are connected to the second terminal ST. In addition, one terminal CBS of the capacitor CB (see Figure 2) is also connected to the second terminal ST.

[0115] The source S of the first transistor Tr1 is connected to the cathode of the first diode D1 and the other terminal CBD of the capacitor CB (see Figure 2). The drain D of the first transistor Tr1 is connected to the drain D of the second transistor Tr2 and the FP terminal of the switching element SD2.

[0116] The gate G of switching element SD2 is connected to the control terminal GT. The gate G of the first transistor Tr1 and the gate G of the second transistor Tr2 are connected to the drain D of the third transistor Tr3 and the cathode K of the second diode D2. The gate G of the third transistor Tr3 is connected to the control terminal GT.

[0117] In the semiconductor devices 5 and 6 according to this embodiment, the switching element SD2 is operated by the control method shown in Figure 2, making it possible to reduce on-resistance and switching loss.

[0118] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0119] (Note 1) First bias terminal and A second bias terminal spaced apart from the first bias terminal, An input terminal spaced apart from the first bias terminal and the second bias terminal, A diode having an anode connected to the first bias terminal, A capacitor having a first terminal connected to the cathode of the diode and a second terminal electrically connected to the second bias terminal, A first transistor including a third terminal connected to the first terminal of the capacitor, a fourth terminal, and a first control terminal for controlling the electrical conduction between the third terminal and the fourth terminal on and off, A second transistor including a fifth terminal connected to the fourth terminal of the first transistor, a sixth terminal connected to the second bias terminal, and a second control terminal for controlling the electrical conduction between the fifth terminal and the sixth terminal on and off, The output terminal is spaced apart from the first bias terminal, the second bias terminal and the input terminal, and is connected to the fourth terminal of the first transistor and the fifth terminal of the second transistor, Equipped with, A control circuit configured to input control signals based on signals input to the input terminals to the first and second control terminals, thereby causing the first and second transistors to alternately turn on and off. (Note 2) The control circuit according to Appendix 1, further comprising a second output terminal spaced apart from the first bias terminal, the second bias terminal, the input terminal, and the output terminal, which directly outputs the signal input to the input terminal. (Note 3) The control circuit according to Appendix 1 or 2, wherein the fourth terminal is the drain terminal of the first transistor, and the fifth terminal is the drain terminal of the second transistor. (Note 4) A second diode having an anode connected to the first bias terminal, A third transistor including a seventh terminal connected to the cathode of the second diode, an eighth terminal connected to the second bias terminal, and a third control terminal for switching the electrical conduction between the seventh terminal and the eighth terminal on and off, Furthermore, The first control terminal of the first transistor and the second control terminal of the second transistor are connected to the seventh terminal of the third transistor. The third control terminal of the third transistor is connected to the input terminal, and is a control circuit according to any one of appendices 1 to 3. (Note 5) A third transistor including a seventh terminal connected to the first bias terminal via a resistor, an eighth terminal connected to the second bias terminal, and a third control terminal for switching the electrical conduction between the seventh and eighth terminals on and off, Furthermore, The first control terminal of the first transistor and the second control terminal of the second transistor are connected to the seventh terminal of the third transistor. The third control terminal of the third transistor is connected to the input terminal, and is a control circuit according to any one of appendices 1 to 3. (Note 6) A control circuit described in any one of the appendices 1 to 5, A switching element connected to the control circuit, Equipped with, The switching element includes a first electrode connected to the first bias terminal of the control circuit, a second electrode connected to the second bias terminal of the control circuit, a third electrode connected to the output terminal of the control circuit, a control electrode connected to the input terminal of the control circuit, and a semiconductor portion electrically connected to the first electrode and the second electrode. The control electrode is configured to control the on / off state of electrical conductivity in the semiconductor portion between the first electrode and the second electrode based on the signal input to the input terminal. The third electrode is provided between the first electrode and the second electrode and faces the semiconductor portion via an insulating film, in a semiconductor device. (Note 7) The semiconductor device according to Appendix 6, wherein the capacitor of the control circuit has a capacitance value greater than the parasitic capacitance between the third electrode and the first electrode. (Note 8) The capacitor of the control circuit is a semiconductor device as described in Appendix 7, which is integrated on the semiconductor part. (Note 9) The control circuit is a semiconductor device as described in any one of appendices 6 to 8, which is integrated on the semiconductor portion. (Note 10) The semiconductor device according to any one of appendices 6 to 8, wherein the control circuit is configured to increase the potential of the third electrode after the switching element is turned on. [Explanation of symbols]

[0120] 1-6...Semiconductor device, 10...Semiconductor part, 11...First semiconductor layer (n-type drift layer), 13...Second semiconductor layer (p-type body layer), 15...Third semiconductor layer (n-type source layer), 17...Fourth semiconductor layer (p-type contact layer), 19...Fifth semiconductor layer (n-type buffer layer), 21...Sixth semiconductor layer, 22...Seventh semiconductor layer, 23...Eighth semiconductor layer, 25...p-type well, 26...n-type contact layer, 20...First electrode, 30...Second electrode, 30c...Contact part, 40...Control electrode (gate electrode), 43...First insulating film (gate insulating film), 45...Second insulating film (interlayer insulating film), 50...Third electrode (field plate), 53...Third insulating film (FP insulating film), 63...Dielectric film, 65...Insulating layer, A...Anode, K...Cathode, S...Source, D...Drain, G...Gate, AL...n-type storage layer CB…Capacitor, CBD, CBS…Terminal, CBR…Capacitor region, CC, CC2, CC3…Control circuit, DE…Delay circuit, FP…Field plate, GT…Control terminal, Id…Drain current, R1…Resistor, RL…Load resistor, Rg, Rge…Gate resistor, SD, SD2…Switching element, SDR…Switching region, SS…Semiconductor substrate, TB1, TB2…Bias terminal, TD1…Diode terminal, TG, TG1, TG2…Trench, TI…Input terminal, TO1, TO2…Output terminal, VCB…Voltage between terminals, VFP…Field plate voltage, Vds…Source-drain voltage, Vg, Vg1, Vg2…Control signal, Vg-in…Gate input signal, Vg-out…Gate output signal, ΔToff…Turn-off time, ΔTon…Turn-on time

Claims

1. The invention comprises a first electrode, a second electrode, a third electrode, a control electrode, and a semiconductor portion electrically connected to the first electrode and the second electrode, The control electrode is configured to control the on / off state of electrical conductivity in the semiconductor portion between the first electrode and the second electrode. The third electrode is provided between the first electrode and the second electrode, and faces the semiconductor portion with an insulating film in between. A control circuit for controlling a switching element, A first bias terminal connected to the first electrode, A second bias terminal is spaced apart from the first bias terminal and connected to the second electrode, An input terminal spaced apart from the first bias terminal and the second bias terminal, A diode having an anode connected to the first bias terminal, A capacitor having a first terminal connected to the cathode of the diode and a second terminal connected to the second bias terminal, A first transistor including a third terminal connected to the first terminal of the capacitor, a fourth terminal, and a first control terminal for controlling the electrical conduction between the third terminal and the fourth terminal on and off, A second transistor including a fifth terminal connected to the fourth terminal of the first transistor, a sixth terminal connected to the second bias terminal, and a second control terminal for controlling the electrical conduction between the fifth terminal and the sixth terminal on and off, The output terminal is spaced apart from the first bias terminal, the second bias terminal and the input terminal, connected to the fourth terminal of the first transistor and the fifth terminal of the second transistor, and connected to the third electrode. A second output terminal is located spaced apart from the first bias terminal, the second bias terminal, the input terminal, and the output terminal, and directly outputs the signal input to the input terminal, and is connected to the control electrode. Equipped with, A control signal based on the signal input to the input terminal is input to the first control terminal and the second control terminal, and the first transistor and the second transistor are configured to turn on and off alternately. When the switching element is in the ON state, the first transistor is in the ON state and the second transistor is in the OFF state. When the switching element is in the off state, the first transistor is in the off state and the second transistor is in the on state. Control circuit.

2. The control circuit according to claim 1, wherein the fourth terminal is the drain terminal of the first transistor, and the fifth terminal is the drain terminal of the second transistor.

3. A second diode having an anode connected to the first bias terminal, A third transistor including a seventh terminal connected to the cathode of the second diode, an eighth terminal connected to the second bias terminal, and a third control terminal for switching the electrical conduction between the seventh terminal and the eighth terminal on and off, Furthermore, The first control terminal of the first transistor and the second control terminal of the second transistor are connected to the seventh terminal of the third transistor. The control circuit according to claim 1, wherein the third control terminal of the third transistor is connected to the input terminal.

4. A third transistor including a seventh terminal connected to the first bias terminal via a resistor, an eighth terminal connected to the second bias terminal, and a third control terminal for controlling the electrical conduction between the seventh terminal and the eighth terminal on and off, Furthermore, The first control terminal of the first transistor and the second control terminal of the second transistor are connected to the seventh terminal of the third transistor. The control circuit according to claim 1, wherein the third control terminal of the third transistor is connected to the input terminal.

5. The switching element, A control circuit according to any one of claims 1 to 4, A semiconductor device equipped with the following features.

6. The semiconductor device according to claim 5, wherein the capacitor of the control circuit has a capacitance value greater than the parasitic capacitance between the third electrode and the first electrode.

7. The semiconductor device according to claim 6, wherein the capacitor of the control circuit is integrated on the semiconductor portion.

8. The semiconductor device according to claim 6, wherein the control circuit is integrated on the semiconductor portion.

9. The semiconductor device according to claim 5, wherein the control circuit is configured to increase the potential of the third electrode after the switching element has been turned on.

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