High-voltage cascaded diode with HEMT and monolithically integrated semiconductor diode

• US 9,142,550 B2
• Filed: 06/18/2013
• Issued: 09/22/2015
• Est. Priority Date: 06/18/2013
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Prechtl, Gerhard, Ostermaier, Clemens, Hberlen, Oliver
• Primary Examiner(s): TRAN, MINH LOAN
• Application Number:
  US13/920,621
• Publication Number:
  US 20140367700A1
• Time in Patent Office: 826 Days
• Field of Search: 257/194, 257/195, 257/476, 438/167, 438/172
• US Class Current: 1/1
• CPC Class Codes: H01L 21/8234 MIS technology , i.e. integration processes of field effect transistors of the conductor-insulator-semiconductor type
• CPC Class Codes: H01L 21/8258 the substrate being a semiconductor, using a combination of technologies covered by H01L21/8206, H01L21/8213 , H01L21/822, H01L21/8252, H01L21/8254 or H01L21/8256
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48464 the other connecting portion not on the bonding area also being a ball bond, i.e. ball-to-ball
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 23/481 Internal lead connections, e.g. via connections, feedthrough structures
• 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 29/1075 of field-effect transistors
• CPC Class Codes: H01L 29/1079 with insulated gate
• CPC Class Codes: H01L 29/1608 Silicon carbide
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/4175 for lateral devices where the connection to the source or drain region is done through at least one part of the semiconductor substrate thickness, e.g. with connecting sink or with via-hole
• CPC Class Codes: H01L 29/778 with two-dimensional charge carrier gas channel, e.g. HEMT ; with two-dimensional charge-carrier layer formed at a heterojunction interface H01L29/803 takes precedence
• 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 29/872 Schottky diodes
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

An embodiment of a cascaded diode having a breakdown voltage exceeding 300V includes an HEMT and a Si Schottky diode. The HEMT includes a gate, a drain, a source, and a two-dimensional electron gas channel region connecting the source and the drain and controlled by the gate. The HEMT has a breakdown voltage exceeding 300V. The Si Schottky diode is monolithically integrated with the HEMT. The Si Schottky diode includes a cathode connected to the source of the HEMT and an anode connected to the gate of the HEMT. The Si Schottky diode has a breakdown voltage less than 300V and a forward voltage less than or equal to 0.4V. The anode of the Si Schottky diode forms the anode of the cascaded diode and the drain of the HEMT forms the cathode of the cascaded diode.

Claims

1. A cascaded diode, comprising:

a III-nitride semiconductor body;

an HEMT having a gate, a drain, a source, and a channel connecting the source and the drain, the channel controlled by the gate and formed by a junction between two materials of the III-nitride semiconductor body with different band gaps; and

a semiconductor diode monolithically integrated with the HEMT, the semiconductor diode having a cathode connected to the source of the HEMT and an anode connected to the gate of the HEMT,

wherein the anode of the semiconductor diode forms the anode of the cascaded diode and the drain of the HEMT forms the cathode of the cascaded diode.

2. The cascaded diode of claim 1, wherein the semiconductor diode is a Si Schottky diode or a SiC Schottky diode.

3. The cascaded diode of claim 1, wherein the semiconductor diode is a Si p-n junction diode.

4. The cascaded diode of claim 1, wherein the HEMT is a GaN HEMT and the semiconductor diode is a GaN diode or a MIS-gated diode.

5. The cascaded diode of claim 1, further comprising:

a Si substrate on which the III-nitride semiconductor body is disposed; and

an electrically conductive plug extending through the III-nitride semiconductor body and connecting the source of the HEMT to the Si substrate.

6. The cascaded diode of claim 5, further comprising a metallization disposed on a side of the Si substrate facing away from the III-nitride semiconductor body, wherein the Si substrate is doped n-type, the cathode of the semiconductor diode is formed by the n-type doped Si substrate and the anode of the semiconductor diode is formed by the metallization disposed on the Si substrate.

7. The cascaded diode of claim 6, wherein the concentration of the n-type doping of the Si substrate is lower in a first region of the Si substrate adjacent the metallization and higher in a second region of the Si substrate spaced apart from the metallization by the first region.

8. The cascaded diode of claim 5, wherein the Si substrate is doped p-type, the plug is a metal plug, the cathode of the semiconductor diode is formed by the metal plug and the anode of the semiconductor diode is formed by the p-type doped Si substrate.

9. The cascaded diode of claim 5, wherein the Si substrate is doped p-type, the plug comprises n-doped polysilicon, the cathode of the semiconductor diode is formed by the n-doped polysilicon plug and the anode of the semiconductor diode is formed by the p-type doped Si substrate.

10. The cascaded diode of claim 5, wherein the plug comprises an n-doped polysilicon region contacting the source of the HEMT and a p-doped polysilicon region spaced apart from the source of the HEMT by the n-doped polysilicon region, the cathode of the semiconductor diode is formed by the n-doped polysilicon region of the plug and the anode of the semiconductor diode is formed by the p-type doped polysilicon region of the plug.

11. The cascaded diode of claim 1, wherein the semiconductor diode is disposed on the III-nitride semiconductor body and comprises:

a heavily n-doped polysilicon region disposed on the side of the III-nitride semiconductor body with the gate of the HEMT;

a lightly n-doped polysilicon region adjacent the heavily n-doped polysilicon region;

an ohmic contact on the heavily n-doped polysilicon region; and

a Schottky contact on the lightly n-doped polysilicon region,

wherein the source of the HEMT is connected to the ohmic contact and the gate of the HEMT is connected to the Schottky contact.

12. The cascaded diode of claim 1, wherein the semiconductor diode is disposed on the III-nitride semiconductor body and comprises:

a heavily p-doped polysilicon region disposed on the side of the III-nitride semiconductor body with the gate of the HEMT;

a lightly p-doped polysilicon region adjacent the heavily n-doped polysilicon region;

an ohmic contact on the heavily p-doped polysilicon region; and

a Schottky contact on the lightly p-doped polysilicon region,

wherein the source of the HEMT is connected to the Schottky contact and the gate of the HEMT is connected to the ohmic contact.

13. The cascaded diode of claim 1, further comprising an electrically conductive plug extending through the III-nitride semiconductor body for connecting the gate of the HEMT to the anode of the semiconductor diode, the electrically conductive plug having insulated sidewalls.

14. A cascaded diode having a breakdown voltage exceeding 300V, comprising:

an HEMT including a gate, a drain, a source, and a two-dimensional electron gas channel region connecting the source and the drain and controlled by the gate, the HEMT having a breakdown voltage exceeding 300V; and

a Si Schottky diode monolithically integrated with the HEMT, the Si Schottky diode including a cathode connected to the source of the HEMT and an anode connected to the gate of the HEMT, the Si Schottky diode having a breakdown voltage less than 300V and a forward voltage less than or equal to 0.4V,

wherein the anode of the Si Schottky diode forms the anode of the cascaded diode and the drain of the HEMT forms the cathode of the cascaded diode.

15. The cascaded diode of claim 14, further comprising:

a Si substrate on which the HEMT is disposed; and

an electrically conductive plug connecting the source of the HEMT to the Si substrate.

16. The cascaded diode of claim 15, further comprising a metallization disposed on a side of the Si substrate facing away from the gate of the HEMT, wherein the Si substrate is doped n-type, the cathode of the Si Schottky diode is formed by the n-type doped Si substrate and the anode of the Si Schottky diode is formed by the metallization disposed on the Si substrate.

17. The cascaded diode of claim 15, wherein the Si substrate is doped p-type, the plug is a metal plug, the cathode of the Si Schottky diode is formed by the metal plug and the anode of the Si Schottky diode is formed by the p-type doped Si substrate.

18. The cascaded diode of claim 14, wherein the Si Schottky diode is disposed on a side of a III-nitride semiconductor body with the gate of the HEMT and the Si Schottky diode comprises:

a heavily n-doped polysilicon region disposed on the side of the III-nitride semiconductor body with the gate of the HEMT;

a lightly n-doped polysilicon region adjacent the heavily n-doped polysilicon region;

an ohmic contact on the heavily n-doped polysilicon region; and

a Schottky contact on the lightly n-doped polysilicon region,

wherein the source of the HEMT is connected to the ohmic contact and the gate of the HEMT is connected to the Schottky contact.

19. The cascaded diode of claim 14, wherein the Si Schottky diode is disposed on a side of a III-nitride semiconductor body with the gate of the HEMT and the Si Schottky diode comprises:

a heavily p-doped polysilicon region disposed on the side of the III-nitride semiconductor body with the gate of the HEMT;

a lightly p-doped polysilicon region adjacent the heavily n-doped polysilicon region;

an ohmic contact on the heavily p-doped polysilicon region; and

a Schottky contact on the lightly p-doped polysilicon region,

wherein the source of the HEMT is connected to the Schottky contact and the gate of the HEMT is connected to the ohmic contact.

20. A method of manufacturing a cascaded diode, the method comprising:

forming an HEMT in a III-nitride semiconductor body, the HEMT having a gate, a drain, a source, and a channel connecting the source and the drain, the channel controlled by the gate and formed by a junction between two materials of the III-nitride semiconductor body with different band gaps;

monolithically integrating a semiconductor diode with the HEMT, the semiconductor diode having a cathode connected to the source of the HEMT and an anode connected to the gate of the HEMT;

connecting an anode terminal of the cascaded diode to the anode of the semiconductor diode; and

connecting a cathode terminal of the cascaded diode to the drain of the HEMT.