Semiconductor Device Having a Bidirectional Switch and Discharge Circuit

• US 20190326280A1
• Filed: 04/23/2018
• Published: 10/24/2019
• Est. Priority Date: 04/23/2018
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Imam, Mohamed, Kim, Hyeongnam, Leong, Kennith Kin, Pandya, Bhargav, Prechtl, Gerhard
• Granted Patent: US 11,862,630 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 21/823885 with a particular manufacturing method of vertical transistor structures, i.e. with channel vertical to the substrate surface with a current flow parallel to the substrate surface H01L21/823821
• CPC Class Codes: H01L 21/8252 the substrate being a semiconductor, using III-V technology H01L21/8258 takes precedence
• CPC Class Codes: H01L 27/0605 integrated circuits made of compound material, e.g. AIIIBV
• CPC Class Codes: H01L 27/0629 in combination with diodes, or resistors, or capacitors
• CPC Class Codes: H01L 27/0727 in combination with diodes, or capacitors or resistors
• CPC Class Codes: H01L 27/0814 Diodes only
• CPC Class Codes: H01L 27/088 the components being field-effect transistors with insulated gate
• CPC Class Codes: H01L 29/1066 Gate region of field-effect devices with PN junction gate
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/205 in different semiconductor regions , e.g. heterojunctions
• CPC Class Codes: H01L 29/42316 for field-effect transistors
• CPC Class Codes: H01L 29/7786 with direct single heterostructure, i.e. with wide bandgap layer formed on top of active layer, e.g. direct single heterostructure MIS-like HEMT
• CPC Class Codes: H01L 29/7787 with wide bandgap charge-carrier supplying layer, e.g. direct single heterostructure MODFET
• CPC Class Codes: H01L 29/861 Diodes
• CPC Class Codes: H03K 17/6871 the output circuit comprising more than one controlled field-effect transistor
• CPC Class Codes: H03K 17/6874 in a symmetrical configuration
• CPC Class Codes: H03K 2217/0009 AC switches, i.e. delivering AC power to a load
• CPC Class Codes: H03K 2217/0018 Special modifications or use of the back gate voltage of a FET

Abstract

A semiconductor device includes a main bi-directional switch formed on a semiconductor substrate and having first and second gates, a first source electrically connected to a first voltage terminal, a second source electrically connected to a second voltage terminal, and a common drain. The semiconductor device further includes a discharge circuit having a plurality of individual transistors or an auxiliary bi-directional switch monolithically integrated with the main bi-directional switch and connected in a common source configuration to the semiconductor substrate. The plurality of individual transistors or the auxiliary bi-directional switch includes a first drain connected to the first source of the main bi-directional switch, a second drain connected to the second source of the main bi-directional switch, and first and second gates each decoupled from gate drive circuitry so that the first and the second gates are controlled at least passively and based on a state of the main bi-directional switch.

Claims

1. A semiconductor device, comprising:

a main bi-directional switch formed on a semiconductor substrate and comprising first and second gates, a first source electrically connected to a first voltage terminal, a second source electrically connected to a second voltage terminal, and a common drain; and

a discharge circuit comprising a plurality of individual transistors or an auxiliary bi-directional switch monolithically integrated with the main bi-directional switch and connected in a common source configuration to the semiconductor substrate, the plurality of individual transistors or the auxiliary bi-directional switch comprising a first drain connected to the first source of the main bi-directional switch, a second drain connected to the second source of the main bi-directional switch, and first and second gates each decoupled from gate drive circuitry so that the first and the second gates are controlled at least passively and based on a state of the main bi-directional switch.

2. The semiconductor device of claim 1,

wherein the main bi-directional switch has four primary operational states:

OFF/OFF in which both gates of the main bi-directional switch are off;

ON/ON in which both gates of the main bi-directional switch are on;

ON/OFF in which the first gate of the main bi-directional switch is on and the second gate of the main bi-directional switch is off; and

OFF/ON in which the first gate of the main bi-directional switch is off and the second gate of the main bi-directional switch is on,

wherein the discharge circuit is configured to automatically discharge the semiconductor substrate to the first voltage terminal and/or the second voltage terminal responsive to the main bi-directional switch transitioning from the ON/OFF state or the OFF/ON state to the ON/ON state.

3. The semiconductor device of claim 1, further comprising:

a first diode and a second diode monolithically integrated with the main bi-directional switch,

wherein the anode of the first diode and the anode of the second diode are connected to the semiconductor substrate,

wherein the cathode of the first diode is connected to the first source of the main bi-directional switch,

wherein the cathode of the second diode is connected to the second source of the main bi-directional switch.

4. The semiconductor device of claim 3, wherein the first and the second gates of the plurality of individual transistors or the auxiliary bi-directional switch of the discharge circuit are connected together and floating.

5. The semiconductor device of claim 3, wherein the first and the second gates of the plurality of individual transistors or the auxiliary bi-directional switch of the discharge circuit are disconnected from one another and each floating.

6. The semiconductor device of claim 3, wherein the first diode and the second diode are each a GaN diode comprising a p-doped region and a first electrode as the anode, and a two-dimensional electron gas and a second electrode as the cathode.

7. The semiconductor device of claim 3, wherein the first diode and the second diode are each a GaN transistor having a gate connected to a source or a drain.

8. The semiconductor device of claim 1, further comprising:

a first diode and a second diode monolithically integrated with the main bi-directional switch,

wherein the anode of the first diode is connected to the first gate of the plurality of individual transistors or the auxiliary bi-directional switch of the discharge circuit,

wherein the cathode of the first diode is connected to the first source of the main bi-directional switch,

wherein the anode of the second diode is connected to the second gate of the plurality of individual transistors or the auxiliary bi-directional switch of the discharge circuit,

wherein the cathode of the second diode is connected to the second source of the main bi-directional switch.

9. The semiconductor device of claim 8, wherein the first diode and the second diode are each a GaN diode comprising a p-doped region and a first electrode as the anode, and a two-dimensional electron gas and a second electrode as the cathode.

10. The semiconductor device of claim 8, wherein the first diode and the second diode are each a GaN transistor having gate connected to a source or a drain.

11. The semiconductor device of claim 8, further comprising:

a third diode and a fourth diode monolithically integrated with the main bi-directional switch,

wherein the anode of the third diode and the anode of the fourth diode are connected to the semiconductor substrate,

wherein the cathode of the third diode is connected to the first source of the main bi-directional switch,

wherein the cathode of the fourth diode is connected to the second source of the main bi-directional switch.

12. The semiconductor device of claim 1, further comprising:

a first diode and a second diode monolithically integrated with the main bi-directional switch,

wherein the anode of the first diode is connected to the second gate of the plurality of individual transistors or the auxiliary bi-directional switch of the discharge circuit,

wherein the cathode of the first diode is connected to the first source of the main bi-directional switch,

wherein the anode of the second diode is connected to the first gate of the plurality of individual transistors or the auxiliary bi-directional switch of the discharge circuit,

wherein the cathode of the second diode is connected to the second source of the main bi-directional switch.

13. The semiconductor device of claim 12, wherein the first diode and the second diode are each a GaN diode comprising a p-doped region and a first electrode as the anode, and a two-dimensional electron gas and a second electrode as the cathode.

14. The semiconductor device of claim 12, wherein the first diode and the second diode are each a GaN transistor having a gate connected to a source or a drain.

15. The semiconductor device of claim 12, further comprising:

a third diode and a fourth diode monolithically integrated with the main bi-directional switch,

wherein the anode of the third diode and the anode of the fourth diode are connected to the semiconductor substrate,

wherein the cathode of the third diode is connected to the first source of the main bi-directional switch,

wherein the cathode of the fourth diode is connected to the second source of the main bi-directional switch.

16. The semiconductor device of claim 12, wherein the semiconductor device is devoid of diode connections between the first source of the main bi-directional switch and the semiconductor substrate, and between the second source of the main bi-directional switch and the semiconductor substrate.

17. The semiconductor device of claim 1, wherein the main bi-directional switch and the plurality of individual transistors or the auxiliary bi-directional switch are each GaN devices.

18. The semiconductor device of claim 1, wherein the plurality of individual transistors or the auxiliary bi-directional switch has an Rdson greater than 1 Ohm, and/or wherein the plurality of individual transistors or the auxiliary bi-directional switch is between 1/50 and 1/100 the size of the main bi-directional switch.

19. The semiconductor device of claim 1, wherein the plurality of individual transistors comprises a plurality of individual HEMT devices connected in a common source configuration so that a first drain provides source functionally in a first direction and a second drain provides the source functionality in a second direction opposite the first direction.

20. A power circuit comprising the semiconductor device of claim 1, wherein the main bi-directional switch is configured to enable bi-directional current flow within the power circuit.