Field-effect semiconductor device having a heterojunction contact

• US 10,461,074 B2
• Filed: 06/28/2018
• Issued: 10/29/2019
• Est. Priority Date: 09/04/2012
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Werner, Wolfgang
• Primary Examiner(s): Pizarro, Marcos D.
• Assistant Examiner(s): Brasfield, Quinton A
• Application Number:
  US16/022,263
• Publication Number:
  US 20180323189A1
• Time in Patent Office: 488 Days
• CPC Class Codes: H01L 27/0629 in combination with diodes, or resistors, or capacitors
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• CPC Class Codes: H01L 29/1095 Body region, i.e. base region, of DMOS transistors or IGBTs cell layout H01L29/0696
• CPC Class Codes: H01L 29/1604 Amorphous materials
• CPC Class Codes: H01L 29/1608 Silicon carbide
• CPC Class Codes: H01L 29/165 in different semiconductor regions , e.g. heterojunctions
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/267 in different semiconductor regions , e.g. heterojunctions H01L29/263 takes precedence
• CPC Class Codes: H01L 29/66068 the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
• CPC Class Codes: H01L 29/66431 with a heterojunction interface channel or gate, e.g. HFET, HIGFET, SISFET, HJFET, HEMT with an active layer made of a group 13/15 material H01L29/66462
• CPC Class Codes: H01L 29/66734 with a step of recessing the gate electrode, e.g. to form a trench gate electrode
• CPC Class Codes: H01L 29/66893 with a PN junction gate, i.e. JFET
• CPC Class Codes: H01L 29/66909 Vertical transistors, e.g. tecnetrons
• CPC Class Codes: H01L 29/66924 with an active layer made of a group 13/15 material H01L29/66446 takes precedence
• CPC Class Codes: H01L 29/7395 Vertical transistors, e.g. vertical IGBT
• CPC Class Codes: H01L 29/78 with field effect produced by an insulated gate H01L29/7725, H01L29/775, H01L29/778 take precedence
• CPC Class Codes: H01L 29/7805 in antiparallel, e.g. freewheel diode
• CPC Class Codes: H01L 29/7806 the other device being a Schottky barrier diode
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236
• CPC Class Codes: H01L 29/8083 Vertical transistors SIT H01L29/7722
• CPC Class Codes: H01L 29/8611 : Planar PN junction diodes
• CPC Class Codes: H01L 29/872 : Schottky diodes
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

According to an embodiment of a semiconductor device, the semiconductor device includes a semiconductor body having a main surface, the semiconductor body including a drift region of monocrystalline SiC, the drift region being of a first conductivity type, and a metallization arranged at the main surface. In a cross-section which is substantially orthogonal to the main surface, the semiconductor body further includes a contact region of the monocrystalline SiC directly adjoining the drift region and the metallization, and an anode region of a semiconductor material having a lower band-gap than the monocrystalline SiC. The contact region is of a second conductivity type. The anode region is in ohmic contact with the metallization and forms a heterojunction with the drift region.

Claims

1. A semiconductor device, comprising:

a semiconductor body having a main surface, the semiconductor body comprising a drift region of monocrystalline SiC, the drift region being of a first conductivity type; and

a metallization arranged at the main surface,

wherein in a cross-section which is substantially orthogonal to the main surface, the semiconductor body further comprises;

a contact region of the monocrystalline SiC directly adjoining the drift region and the metallization, the contact region being of a second conductivity type; and

an anode region of a semiconductor material having a lower band-gap than the monocrystalline SiC, the anode region being in ohmic contact with the metallization and forming a heterojunction with the drift region.

2. The semiconductor device of claim 1, wherein the anode region directly adjoins the contact region.

3. The semiconductor device of claim 1, wherein the contact region directly adjoins the metallization at the main surface.

4. The semiconductor device of claim 1, further comprising in the vertical cross-section, a further contact region of the monocrystalline SiC directly adjoining the drift region and the metallization, the further contact region being of the second conductivity type, wherein the heterojunction extends from the contact region to the further contact region.

5. The semiconductor device of claim 1, wherein an extension of the contact region in a vertical direction perpendicular to the main surface is larger than an extension of the anode region in the vertical direction.

6. The semiconductor device of claim 1, wherein the semiconductor material of the anode region is a non-crystalline band-gap material.

7. The semiconductor device of claim 1, wherein a maximum doping concentration of the anode region is at least three orders of magnitude higher than a maximum doping concentration of the drift region.

8. The semiconductor device of claim 1, wherein the anode region and the drift region form a diode.

9. The semiconductor device of claim 1, further comprising a source region of the monocrystalline SiC in ohmic contact with the metallization, the source region being of the first conductivity type and having a higher maximum doping concentration than the drift region, wherein the heterojunction and the source region do not overlap in a projection onto the main surface.

10. The semiconductor device of claim 9, further comprising a gate electrode arranged in a vertical trench extending from the main surface at least partly in the drift region, the gate electrode being insulated from the source region and the drift region by a gate dielectric region.

11. The semiconductor device of claim 1, further comprising a body region of the monocrystalline SiC, the body region being of the second conductivity type and having a lower doping concentration than the contact region, the contact region being arranged between the body region and the anode region and between the body region and the metallization.

12. The semiconductor device of claim 11, further comprising a gate electrode arranged in a vertical trench extending from the main surface at least partly in the drift region, the gate electrode being insulated from the drift region and the body region by a gate dielectric region.

13. The semiconductor device of claim 1, wherein the anode region is of the second conductivity type.

14. The semiconductor device of claim 1, wherein the semiconductor material of the anode region is silicon or germanium.

15. The semiconductor device of claim 1, further comprising a gate electrode arranged in a vertical trench extending from the main surface at least partly in the drift region, the gate electrode being insulated from the monocrystalline SiC by a gate dielectric region.