Semiconductor device and semiconductor module

Abstract

To provide a semiconductor device that controls the operation of a predetermined first transistor unit by using a bootstrap capacitor.SOLUTION: In a semiconductor module 300, a semiconductor device 100 comprises: a high-side circuit 10 that has a power input terminal VB and controls the operation of a first transistor unit 110; a bootstrap transistor unit 30 that is connected between a power terminal VCC and a bootstrap capacitor 130; and a sense transistor unit 40 that has a first terminal Ts1 functioning as one of a source or drain terminal and connected with the power input terminal, a second terminal Ts2 functioning as the other of the source or drain terminal, and a gate terminal G connected with the power terminal, and that controls on / off of the bootstrap transistor unit. The concentration of impurities in a back gate region of the sense transistor unit is 1E10 cm-3 or more and 1E15 cm-3 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor device and a semiconductor module. [Background technology]

[0002] Patent document 1 discloses a "bootstrap capacitance charging circuit." [Prior art document] [Patent Documents] Patent Document 1: Japanese Patent Application Laid-Open No. 9-65571

[0003] A semiconductor device is provided that charges a bootstrap capacitor while suppressing the substrate bias effect. Summary of the Invention

[0004] In a first aspect of the present invention, there is provided a semiconductor device for controlling the operation of a predetermined first transistor unit using a bootstrap capacitor, the semiconductor device comprising: a high-side circuit having a power supply input terminal electrically connected to the bootstrap capacitor and controlling the operation of the first transistor unit; a bootstrap transistor unit electrically connected between the power supply terminal of the semiconductor device and the bootstrap capacitor; and a sense transistor unit having a first terminal functioning as one of a source terminal or a drain terminal and electrically connected to the power supply input terminal, a second terminal functioning as the other of the source terminal or the drain terminal, and a gate terminal electrically connected to the power supply terminal, for controlling the on / off of the bootstrap transistor unit. An impurity concentration in a back gate region of the sense transistor unit is 1E10 cm -3 Above, 1E15cm -3 It may be the following:

[0005] In a second aspect of the present invention, there is provided a semiconductor module comprising: a semiconductor device according to the first aspect of the present invention; a first transistor section having a gate terminal electrically connected to an output terminal of the high-side circuit; a second transistor section having a gate terminal electrically connected to an output terminal of a low-side circuit; and a bootstrap capacitor having one end electrically connected to the power supply input terminal of the high-side circuit and the other end electrically connected to a connection point between the first transistor section and the second transistor section.

[0006] The above summary of the invention does not list all of the features of the present invention, and subcombinations of these features may also be inventions. [Brief explanation of the drawings]

[0007] [Figure 1] 1 shows an example of a circuit diagram of a semiconductor module 300 according to an embodiment. [Figure 2] 1 shows an example of a cross-sectional view of a transistor portion included in a semiconductor device 100. FIG. [Figure 3] 1 shows an example of a circuit diagram of a semiconductor module 500 as a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0009] 1 shows an example of a circuit diagram of a semiconductor module 300 according to an embodiment. The semiconductor module 300 of this embodiment includes a semiconductor device 100 for controlling a first transistor section 110 and a second transistor section 120.

[0010] The semiconductor device 100 is electrically connected to the bootstrap capacitor 130 and controls the operation of a predetermined transistor to be controlled. The semiconductor device 100 of this example controls the operation of each of the first transistor section 110 and the second transistor section 120. The semiconductor device 100 may function as a gate driver IC (Integrated Circuit) for controlling the driving of the transistors.

[0011] The first transistor unit 110 and the second transistor unit 120 may be switching elements of a power conversion circuit such as an inverter. The first transistor unit 110 and the second transistor unit 120 may be any transistor such as an IGBT or a MOSFET. The first transistor unit 110 and the second transistor unit 120 may each be an N-channel transistor or a P-channel transistor.

[0012] The semiconductor device 100 includes a high-side circuit 10, a low-side circuit 20, a bootstrap transistor section 30, a sense transistor section 40, a comparator 50, and a boost circuit 60.

[0013] The high-side circuit 10 is electrically connected to the gate terminal of the first transistor section 110 and controls the operation of the first transistor section 110. The high-side circuit 10 has a power supply input terminal VB, a terminal VS, and an output terminal HO. The power supply input terminal VB is electrically connected to the bootstrap capacitor 130. The terminal VS is electrically connected to a connection point 115 between the first transistor section 110 and the second transistor section 120. The output terminal HO is electrically connected to the gate terminal of the first transistor section 110.

[0014] The low-side circuit 20 is electrically connected to the gate terminal of the second transistor section 120 and controls the operation of the second transistor section 120. The low-side circuit 20 is electrically connected to the power supply terminal VCC and operates using the power supply voltage Vcc as a driving voltage. The low-side circuit 20 has an output terminal LO electrically connected to the gate terminal of the second transistor section 120.

[0015] The bootstrap transistor section 30 functions as a rectifying element for charging the bootstrap capacitor 130. The bootstrap transistor section 30 has a first terminal Tb1, a second terminal Tb2, and a gate terminal. The bootstrap transistor section 30 is electrically connected between the bootstrap capacitor 130 and a power supply terminal VCC. The first terminal Tb1 is electrically connected to the power supply input terminal VB and the high-voltage side terminal of the bootstrap capacitor 130. The second terminal Tb2 is electrically connected to the power supply terminal VCC.

[0016] The sense transistor section 40 controls the on / off of the bootstrap transistor section 30. The sense transistor section 40 may be connected in parallel with the bootstrap transistor section 30. The sense transistor section 40 has a first terminal Ts1, a second terminal Ts2, and a gate terminal. The gate terminal of the sense transistor section 40 is electrically connected to a power supply terminal VCC. The first terminal Ts1 is electrically connected to a power supply input terminal VB and the high-voltage side terminal of the bootstrap capacitor 130. The second terminal Ts2 is electrically connected to the comparator 50.

[0017] The first terminal Ts1 functions as either the source terminal or the drain terminal of the sense transistor section 40, and is electrically connected to the power supply input terminal VB. The second terminal Ts2 functions as the other of the source terminal or the drain terminal of the sense transistor section 40. That is, the first terminal Ts1 and the second terminal Ts2 function as either the source terminal or the drain terminal depending on the magnitude of the respective terminal voltages. Of the first terminal Ts1 and the second terminal Ts2, the terminal with the larger terminal voltage may function as the drain terminal, and the terminal with the smaller terminal voltage may function as the source terminal.

[0018] The comparator 50 determines whether to turn on the bootstrap transistor unit 30 based on a comparison between the power supply voltage Vcc and the voltage at the second terminal Ts2. The comparator 50 has a first input terminal and a second input terminal. The first input terminal of the comparator 50 is electrically connected to the power supply terminal VCC. The second input terminal of the comparator 50 is electrically connected to the second terminal Ts2.

[0019] In this example, the comparator 50 operates when the power supply voltage Vcc is lower than the voltage at the second terminal Ts2. expensive On the other hand, the comparator 50 of this example outputs a signal to turn on the bootstrap transistor unit 30 when the power supply voltage Vcc is equal to or lower than the voltage of the second terminal Ts2. below In this case, a signal is output to turn off the bootstrap transistor section 30.

[0020] The boost circuit 60 is electrically connected to the output terminal of the comparator 50 and controls the operation of the bootstrap transistor unit 30. The output terminal of the boost circuit 60 is connected to the gate terminal of the bootstrap transistor unit 30. When the bootstrap transistor unit 30 is turned on, the boost circuit 60 boosts the gate voltage of the bootstrap transistor unit 30 to a voltage higher than the power supply voltage Vcc. In this way, by boosting the gate voltage of the bootstrap transistor unit 30 to a voltage higher than the power supply voltage Vcc, the current capability of the bootstrap transistor unit 30 can be improved.

[0021] The first transistor section 110 and the second transistor section 120 are electrically connected to each other. In this example, the first transistor section 110 and the second transistor section 120 are connected to each other at a connection point 115. The connection point 115 may be electrically connected to a load via an output terminal OUT.

[0022] The first transistor section 110 is provided in the upper arm and may function as a high-side switch element. The first transistor section 110 has a gate terminal electrically connected to the output terminal HO of the high-side circuit 10. In one example, one end of the first transistor section 110 is electrically connected to the DC input power supply Vhv, and the other end is electrically connected to the second transistor section 120 and the output terminal OUT.

[0023] The second transistor section 120 is provided in the lower arm and may function as a low-side switch element. The second transistor section 120 has a gate terminal electrically connected to the output terminal LO of the low-side circuit 20. In one example, one end of the second transistor section 120 is electrically connected to the first transistor section 110 and the output terminal OUT, and the other end is set to a reference potential.

[0024] One end of the bootstrap capacitor 130 is electrically connected to the power supply input terminal VB of the high-side circuit 10. The other end of the bootstrap capacitor 130 is electrically connected to the connection point 115 between the first transistor section 110 and the second transistor section 120. One end of the bootstrap capacitor 130 is a high-voltage side terminal, and the other end is a low-voltage side terminal.

[0025] To turn on the first transistor unit 110, it is necessary to apply a gate voltage exceeding the threshold voltage Vth between the gate and source of the first transistor unit 110. However, because the source voltage rises to the voltage of the DC input power supply Vhv, it is necessary to apply a gate voltage higher than the voltage of the DC input power supply Vhv. The semiconductor device 100 of this example can apply a gate voltage exceeding the threshold voltage Vth to the first transistor unit 110 by charging the bootstrap capacitor 130 using the power supply voltage Vcc.

[0026] Next, the operation of the semiconductor device 100 will be described.

[0027] When the voltage Vb at the power supply input terminal VB is lower than the power supply voltage Vcc (i.e., Vcc>Vb), the bootstrap transistor unit 30 is controlled to be in a conductive state. For example, when Vcc>Vb, the sense transistor unit 40 turns on, and the voltages at the first terminal Ts1 and the second terminal Ts2 become equal. When the voltage at the second terminal Ts2 becomes lower than the power supply voltage Vcc, the comparator 50 outputs an output signal to turn on the bootstrap transistor unit 30. The boost circuit 60 boosts the gate voltage in response to the output signal from the comparator 50, turning on the bootstrap transistor unit 30.

[0028] On the other hand, when the voltage Vb at the power supply input terminal VB is equal to or higher than the power supply voltage Vcc (i.e., Vcc≦Vb), the bootstrap transistor unit 30 is controlled to be in a non-conductive state. For example, when Vcc≦Vb, the sense transistor unit 40 is turned off. When the sense transistor unit 40 is turned off, the comparator 50 outputs an output signal to turn off the bootstrap transistor unit 30.

[0029] In this way, the semiconductor device 100 of this example controls the on / off of the bootstrap transistor unit 30 in accordance with the relationship between the voltage Vb at the power supply input terminal VB and the power supply voltage Vcc, thereby controlling the charging of the bootstrap capacitor 130 and maintaining the voltage Vb at the power supply input terminal VB at the power supply voltage Vcc.

[0030] Although the semiconductor module 300 of this example includes two transistors, the first transistor unit 110 and the second transistor unit 120, it may include three or more transistor units. In one example, the semiconductor module 300 includes six transistor units to function as a three-phase inverter. The semiconductor module 300 may include one gate driver IC as the semiconductor device 100 and control the operation of the six transistor units. The semiconductor module 300 may also include multiple semiconductor devices 100 and control the operation of the six transistor units.

[0031] By using the bootstrap transistor section 30 and the sense transistor section 40, the semiconductor device 100 can suppress a voltage drop in the power supply voltage Vcc due to the forward voltage of the diode and charge the bootstrap capacitor 130 to the power supply voltage Vcc. This makes it easier to maintain the voltage Vb at the power supply input terminal VB at the power supply voltage Vcc, making it easier to ensure a voltage margin for the high-side circuit 10. The semiconductor device 100 of this example does not require high-voltage diodes and can be built into the ICs of the high-side circuit 10 and the low-side circuit 20.

[0032] The semiconductor device 100 of this example uses the bootstrap transistor section 30 and the sense transistor section 40 to charge the bootstrap capacitor 130 regardless of whether the low-side circuit 20 is on or off. This maintains the capacitance of the bootstrap capacitor 130, making it easier to drive the high-side circuit 10 and improving the current characteristics of the semiconductor module 300.

[0033] 2 shows an example of a cross-sectional view of a transistor included in the semiconductor device 100. The semiconductor device 100 of this example includes a semiconductor substrate 200. The semiconductor device 100 may include, above the semiconductor substrate 200, a first wiring unit 216, a second wiring unit 226, a gate electrode 232, and a gate wiring unit 234.

[0034] The transistor in this example may be any transistor provided in the semiconductor device 100. In this example, the transistor section of the sense transistor section 40 will be described, but a similar transistor structure may also be applied to the transistor section of the bootstrap transistor section 30. The transistor structures of the bootstrap transistor section 30 and the sense transistor section 40 may be the same or different.

[0035] The semiconductor substrate 200 may be a P-type semiconductor substrate made of any semiconductor material such as silicon. The conductivity type of the semiconductor substrate 200 may be P-type. The semiconductor substrate 200 may be set to a predetermined reference potential. The semiconductor substrate 200 may be set to a ground potential GND.

[0036] The semiconductor substrate 200 includes a substrate region 202, a first semiconductor region 212, a first contact region 214, a second semiconductor region 222, and a second contact region 224. An element isolation film 240 and an insulating film 242 may be provided on the upper surface of the semiconductor substrate 200. The conductivity type of the first semiconductor region 212 and the second semiconductor region 222 is, for example, N- type. The impurity concentration of the first contact region 214 may be higher than the impurity concentration of the first semiconductor region 212. The impurity concentration of the second contact region 224 may be higher than the impurity concentration of the second semiconductor region 222. The conductivity type of the first contact region 214 and the second contact region 224 is, for example, N+ type.

[0037] The isolation film 240 may be a LOCOS film made of SiO 2. The isolation film 240 may be provided to extend in the depth direction of the semiconductor substrate 200. That is, a portion of the isolation film 240 may be buried in the semiconductor substrate 200.

[0038] The insulating film 242 may be an oxide film such as SiO2. The insulating film 242 may be a thermal oxide film formed by annealing the semiconductor substrate 200. The insulating film 242 may be provided between the gate electrode 232 and the semiconductor substrate 200 and may function as a gate oxide film.

[0039] The first wiring portion 216 may function as a first terminal Ts1 of the sense transistor portion 40. The second wiring portion 226 may function as a second terminal Ts2 of the sense transistor portion 40. The gate wiring portion 234 may function as a gate terminal of the sense transistor portion 40. The material of the gate electrode 232 may be polysilicon. The material of the gate wiring portion 234 may be a metal such as aluminum.

[0040] When the transistor section of this example is the bootstrap transistor section 30, the first wiring section 216 may function as a first terminal Tb1 of the bootstrap transistor section 30. The second wiring section 226 may function as a second terminal Tb2 of the bootstrap transistor section 30. The gate electrode 232 may function as a gate terminal of the bootstrap transistor section 30. The semiconductor device 100 may include a first field plate 218 and a second field plate 238.

[0041] The material of the first field plate 218 and the second field plate 238 may be polysilicon, a metal such as aluminum, a metal silicide such as aluminum silicide (AlSi) or nickel silicide (NiSi), or another conductor. The material of the first field plate 218 and the second field plate 238 may be the same material or different materials. The first field plate 218 and the second field plate 238 may extend from the upper surface of the insulating film 242 to the upper surface of the element isolation film 240. The first field plate 218 and the second field plate 238 may be formed in the same manufacturing process.

[0042] The first field plate 218 may be electrically connected to the first wiring portion 216. The second field plate 238 may be electrically connected to the gate wiring portion 234. The second field plate 238 may be formed integrally with the gate electrode 232 using the same material.

[0043] The back gate region 204 is provided on the upper surface side of the semiconductor substrate 200, facing the gate electrode 232. In this example, the back gate region 204 is provided on the upper surface side of the semiconductor substrate 200, between the first semiconductor region 212 and the second semiconductor region 222. When the transistor section is an N-channel, the conductivity type of the back gate region 204 may be P-type. The back gate region 204 is a region that faces the region in which the gate electrode 232 is provided, with the insulating film 242 sandwiched therebetween. In other words, the back gate region 204 may be a region in which an N-type inversion layer is formed by application of a gate voltage.

[0044] The impurity concentration of the back gate region 204 is 1E10 cm -3 Above, 1E15cm -3 The impurity concentration of the back gate region 204 may be 1E13 cm -3 Above, 1E15cm -3 The impurity concentration of the back gate region 204 may be 1E10 cm -3 By setting the impurity concentration of the back gate region 204 to 1E15 cm or more, a sufficient potential barrier is formed at the PN junction between the back gate region 204 and the first semiconductor region 212 when reverse bias is applied, allowing the transistor section to function as a rectifying element. -3 By setting the threshold voltage to the value below, it is possible to lower the threshold voltage and control the on / off of the transistor section even when the voltage Vb at the power supply input terminal VB approaches the power supply voltage Vcc.

[0045] The impurity concentration of the back gate region 204 may be the substrate concentration of the semiconductor substrate 200 in which the transistor portion is provided. The impurity concentration of the back gate region 204 may be higher than the substrate concentration of the semiconductor substrate 200. The substrate concentration of the semiconductor substrate 200 may be the impurity concentration of a region of the semiconductor substrate 200 that is not ion-implanted. The composition of the back gate region 204 may be the same as the composition of the substrate region 202.

[0046] The conditions for the back gate region 204 in this example may be applied to both the bootstrap transistor section 30 and the sense transistor section 40. The impurity concentration of the back gate region 204 of the sense transistor section 40 may be the substrate concentration of the semiconductor substrate 200 in which the sense transistor section 40 is provided. The impurity concentration of the back gate region 204 of the bootstrap transistor section 30 may be the substrate concentration of the semiconductor substrate 200 in which the bootstrap transistor section 30 is provided.

[0047] The channel length of the transistor portion may be 10 μm or more and 60 μm or less. The channel length of the transistor portion is the distance between the source region and the drain region formed in the semiconductor substrate 200. The channel length of the transistor portion may be the distance between the first contact region 214 and the second contact region 224. The channel length of the transistor portion may be the distance between the electrode in contact with the first contact region 214 and the electrode in contact with the second contact region 224 on the upper surface of the semiconductor substrate 200.

[0048] The semiconductor device 100 may be a monolithic gate driver IC. The bootstrap transistor section 30 and the sense transistor section 40 may be provided on the same semiconductor substrate 200. The high-side circuit 10, the low-side circuit 20, the bootstrap transistor section 30, and the sense transistor section 40 may be provided on the same semiconductor substrate 200.

[0049] In the semiconductor device 100 of this example, the impurity concentration of the back gate region 204 is set to 1E10 cm -3 Above, 1E15cm -3 By setting the following, it is possible to suppress an increase in the threshold voltage Vth due to the substrate bias effect, and thus it is possible to maintain the charge of the bootstrap capacitor 130 and improve the charging efficiency even when the voltage Vb at the power supply input terminal VB approaches the power supply voltage Vcc.

[0050] 3 shows an example of a circuit diagram of a semiconductor module 500, which is a comparative example. The semiconductor module 500 includes a bootstrap diode 530 electrically connected to the high-voltage terminal of the bootstrap capacitor 130, and controls charging of the bootstrap capacitor 130. A semiconductor device 550 of the semiconductor module 500 includes a high-side circuit 510 and a low-side circuit 520.

[0051] When the first transistor unit 110 is off and the second transistor unit 120 is on, the bootstrap diode 530 is forward biased and passes current from the power supply terminal VCC toward the bootstrap capacitor 130. On the other hand, when the first transistor unit 110 is on and the second transistor unit 120 is off, the bootstrap diode 530 is reverse biased and prevents a reverse current flow.

[0052] When the bootstrap diode 530 is used, a voltage drop equivalent to the forward voltage occurs, making it impossible to raise the voltage Vb at the power supply input terminal VB of the high-side circuit 510 to the power supply voltage Vcc. Furthermore, measures must be taken to prevent parasitic current flowing into the semiconductor substrate when the bootstrap diode 530 operates in the forward direction, making it difficult to incorporate the bootstrap diode 530 into the semiconductor device 550, which is a gate driver IC. Therefore, the bootstrap diode 530 is provided externally to the semiconductor device 550, which is a gate driver IC.

[0053] In contrast, the semiconductor device 100 of the embodiment can incorporate the bootstrap transistor section 30, the sense transistor section 40, the comparator 50, the boost circuit 60, and the like into a single gate driver IC, eliminating the need to attach an external rectifier circuit for charging the bootstrap capacitor 130 to the outside of the semiconductor device 100, thereby reducing the mounting area.

[0054] Here, if the bootstrap diode 530 is simply replaced with a transistor, the gate of the transistor may not be able to be turned on unless there is a power supply with a voltage equal to or higher than the power supply voltage Vcc. On the other hand, the semiconductor device 100 of the embodiment uses the boost circuit 60, so that the operation of the bootstrap transistor unit 30 can be controlled without separately providing a power supply voltage higher than the power supply voltage Vcc. Therefore, the charging efficiency of the bootstrap capacitor 130 can be improved compared to when the bootstrap diode 530 is simply replaced with a transistor.

[0055] (Appendix 1) A semiconductor device for controlling an operation of a predetermined first transistor portion using a bootstrap capacitor, a high-side circuit having a power supply input terminal electrically connected to the bootstrap capacitor and controlling an operation of the first transistor unit; a bootstrap transistor section electrically connected between a power supply terminal of the semiconductor device and the bootstrap capacitor; a sense transistor section for controlling on / off of the bootstrap transistor section, the sense transistor section having a first terminal that functions as one of a source terminal or a drain terminal and is electrically connected to the power supply input terminal, a second terminal that functions as the other of the source terminal or the drain terminal, and a gate terminal that is electrically connected to the power supply terminal; Equipped with The impurity concentration of the back gate region of the sense transistor section is 1E10 cm -3 Above, 1E15cm -3 is Semiconductor device.

[0056] (Appendix 2) The impurity concentration of the back gate region of the sense transistor section is the substrate concentration of the semiconductor substrate on which the sense transistor section is provided. 2. The semiconductor device according to claim 1.

[0057] (Appendix 3) The channel length of the sense transistor portion is 10 μm or more and 60 μm or less. 3. The semiconductor device according to claim 1 or 2.

[0058] (Appendix 4) The bootstrap transistor section and the sense transistor section are provided on the same semiconductor substrate. 4. The semiconductor device according to claim 1.

[0059] (Appendix 5) The semiconductor substrate is set to a predetermined reference potential. 5. The semiconductor device according to claim 4.

[0060] (Appendix 6) The impurity concentration of the back gate region of the bootstrap transistor section is the substrate concentration of the semiconductor substrate on which the bootstrap transistor section is provided. 6. The semiconductor device according to any one of claims 1 to 5.

[0061] (Appendix 7) a comparator having a first input terminal electrically connected to the power supply terminal and a second input terminal electrically connected to the second terminal; 7. The semiconductor device according to any one of claims 1 to 6.

[0062] (Appendix 8) a booster circuit electrically connected to the output terminal of the comparator, for boosting the gate voltage of the bootstrap transistor unit to a voltage higher than the power supply voltage of the power supply terminal; 8. The semiconductor device according to claim 7.

[0063] (Appendix 9) a low-side circuit for controlling the operation of a second transistor section electrically connected to the first transistor section; 9. The semiconductor device according to any one of claims 1 to 8.

[0064] (Appendix 10) The high-side circuit, the low-side circuit, the bootstrap transistor section, and the sense transistor section are provided on the same semiconductor substrate. 10. The semiconductor device according to claim 9.

[0065] (Appendix 11) A semiconductor device according to any one of Supplementary Notes 1 to 10; a first transistor unit having a gate terminal electrically connected to an output terminal of the high-side circuit; a second transistor unit having a gate terminal electrically connected to the output terminal of the low-side circuit; a bootstrap capacitor having one end electrically connected to the power supply input terminal of the high-side circuit and the other end electrically connected to the connection point of the first transistor unit and the second transistor unit; Semiconductor module.

[0066] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0067] It should be noted that the execution order of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order. [Explanation of symbols]

[0068] 10 High-side circuit, 20 Low-side circuit, 30 Bootstrap transistor section, 40 Sense transistor section, 50 Comparator, 60 Boost circuit, 110 First transistor section, 115 Connection point, 120 Second transistor section, 130 Bootstrap capacitor, 100 Semiconductor device, 200 Semiconductor substrate, 202 Substrate region, 204 Backgate region, 212 First semiconductor region, 214 First contact region region, 216...first wiring portion, 218...first field plate, 222...second semiconductor region, 224...second contact region, 226...second wiring portion, 232...gate electrode, 234...gate wiring portion, 238...second field plate, 240...element isolation film, 242...insulating film, 300...semiconductor module, 500...semiconductor module, 510...high side circuit, 520...low side circuit, 530...bootstrap diode, 550...semiconductor device

Claims

1. A semiconductor device for controlling an operation of a predetermined first transistor portion using a bootstrap capacitor, a high-side circuit having a power supply input terminal electrically connected to the bootstrap capacitor and controlling an operation of the first transistor unit; a bootstrap transistor section electrically connected between a power supply terminal of the semiconductor device and the bootstrap capacitor; a sense transistor section for controlling on / off of the bootstrap transistor section, the sense transistor section having a first terminal that functions as one of a source terminal or a drain terminal and is electrically connected to the power supply input terminal, a second terminal that functions as the other of the source terminal or the drain terminal, and a gate terminal that is electrically connected to the power supply terminal; Equipped with The impurity concentration of the back gate region of the bootstrap transistor section and the impurity concentration of the back gate region of the sense transistor section are 1E10 cm －３ Above, 1E15cm －３ is Semiconductor device.

2. The impurity concentration of the back gate region of the sense transistor section is the substrate concentration of the semiconductor substrate on which the sense transistor section is provided. The semiconductor device according to claim 1 .

3. The channel length of the sense transistor portion is 10 μm or more and 60 μm or less. The semiconductor device according to claim 1 .

4. The bootstrap transistor section and the sense transistor section are provided on the same semiconductor substrate. The semiconductor device according to claim 1 .

5. The semiconductor substrate is set to a predetermined reference potential. The semiconductor device according to claim 4 .

6. The impurity concentration of the back gate region of the bootstrap transistor section is the substrate concentration of the semiconductor substrate on which the bootstrap transistor section is provided. The semiconductor device according to claim 1 .

7. a comparator having a first input terminal electrically connected to the power supply terminal and a second input terminal electrically connected to the second terminal; The semiconductor device according to claim 1 .

8. a booster circuit electrically connected to the output terminal of the comparator, for boosting the gate voltage of the bootstrap transistor unit to a voltage higher than the power supply voltage of the power supply terminal; The semiconductor device according to claim 7 .

9. a low-side circuit for controlling the operation of a second transistor section electrically connected to the first transistor section; The semiconductor device according to claim 1 .

10. The high-side circuit, the low-side circuit, the bootstrap transistor section, and the sense transistor section are provided on the same semiconductor substrate. The semiconductor device according to claim 9 .

11. The conductivity type of the back gate region of the bootstrap transistor section and the back gate region of the sense transistor section is P type. The semiconductor device according to claim 1 .

12. A semiconductor device according to any one of claims 1 to 11; a first transistor unit having a gate terminal electrically connected to an output terminal of the high-side circuit; a second transistor unit having a gate terminal electrically connected to an output terminal of the low-side circuit; a bootstrap capacitor having one end electrically connected to the power supply input terminal of the high-side circuit and the other end electrically connected to the connection point of the first transistor unit and the second transistor unit; Semiconductor module.

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