FORMING AN ELECTRONIC DEVICE, SUCH AS A JBS OR MPS DIODE, BASED ON 3C-SIC, AND 3C-SIC ELECTRONIC DEVICE

Abstract

Method for manufacturing an electronic device, comprising the steps of: forming, at a front side of a solid body of 4H-SiC having a first electrical conductivity, at least one implanted region having a second electrical conductivity opposite to the first electrical conductivity; forming, on the front side, a 3C-SiC layer; and forming, in the 3C-SiC layer, an ohmic contact region which extends through the entire thickness of the 3C-SiC layer, up to reaching the implanted region. A silicon layer may be present on the 3C-SiC layer; in this case, the ohmic contact also extends through the silicon layer.

Description

Claims

1. A method for manufacturing an electronic device, the method comprising: forming, at a front side of a solid body of 4H-SiC having a first electrical conductivity, at least one implanted region having a second electrical conductivity opposite to the first electrical conductivity;forming, on the front side, a 3C-SiC layer; andforming, in the 3C-SiC layer, an ohmic contact region extending through an entire thickness of the 3C-SiC layer, up to reaching the implanted region.

2. The method according to claim 1, wherein forming the 3C-SiC layer includes growing 3C-SiC by a vapor-liquid-sold technique or a sublimation epitaxy technique.

3. The method according to claim 1, wherein forming the 3C-SiC layer includes: heating, through a LASER beam, at least one portion of the front side of the solid body, at least up to a melting temperature of the 4H-SiC material; andallowing the cooling and crystallization of the melted portion of the solid body, forming a stack of superimposed layers including: the 3C-SiC layer in contact with the solid body, a silicon layer on the 3C-SiC layer, and a carbon-rich layer on the silicon layer.

4. The method according to claim 3, further comprising completely removing the carbon-rich layer and the silicon layer, exposing the 3C-SiC layer.

5. The method according to claim 4, wherein completely removing the carbon-rich layer and the silicon layer includes oxidating the silicon layer and the carbon-rich layer, and subsequently etching the oxidized silicon layer and the oxidized carbon-rich layer.

6. The method according to claim 3, further comprising completely removing the carbon-rich layer exposing the silicon layer.

7. The method according to claim 6, wherein completely removing the carbon-rich layer includes performing a selective etching for removing the carbon-rich layer preserving the silicon layer.

8. The method according to claim 6, further comprising forming the ohmic contact region also through the entirety of the thickness of the silicon layer, up to reaching the implanted region.

9. The method according to claim 1, further comprising forming, on the 3C-SiC layer and on the ohmic contact region, a metal layer, thus forming a Schottky diode between the metal layer and the 3C-SiC layer and, simultaneously, a junction-barrier, JB, diode between the metal layer and the ohmic contact region.

10. The method according to claim 9, further comprising: forming, at the metal layer, a first electrical terminal common to the JB diode and Schottky diode; andforming, at a rear side opposite to the front side of the solid body, a second electrical terminal common to the JB diode and Schottky diode.

11. The method according to claim 1, wherein the electronic device is one of: a Merged-PiN-Schottky, MPS, device; a Junction Barrier Schottky, JBS, device; a MOSFET; an IGBT; a JFET; a DMOS.

12. An electronic device, comprising: a solid body of 4H-SiC having a first electrical conductivity;at least one implanted region having a second electrical conductivity opposite to the first electrical conductivity extending at a front side of the solid body;a 3C-SiC layer on the front side; andan ohmic contact region through an entire thickness of the 3C-SiC layer, up to reaching the implanted region.

13. The device according to claim 12, further comprising a silicon layer on the 3C-SiC layer, the ohmic contact region also extending through the entire thickness of the silicon layer, up to reaching the implanted region.

14. The device according to claim 12, wherein the solid body includes: a substrate of 4H-SiC; andan epitaxial layer of 4H-SiC on the substrate, wherein the epitaxial layer is a drift layer of the electronic device.

15. The device according to claim 12, wherein the first electrical conductivity is of N-type, and the second electrical conductivity is of P-type.

16. The device according to claim 11, further comprising a metal layer on the 3C-SiC layer and on the ohmic contact region, thus forming a Schottky diode between the metal layer and the 3C-SiC layer and a junction-barrier, JB, diode between the metal layer and the ohmic contact region.

17. The device according to claim 15, further comprising: a first electrical terminal common to the JB diode and Schottky diode at the metal layer; anda second electrical terminal common to the JB diode and Schottky diode at a rear side opposite to the front side of the solid body.

18. The device according to claim 11, wherein the electronic device is one of: a Merged-PiN-Schottky, MPS, device; a Junction Barrier Schottky, JBS, device; a MOSFET; an IGBT; a JFET; a DMOS.

19. An electronic device, comprising: a body of 4H-SiC having a first conductivity type;an implanted region of a second conductivity type in the body extending from a top surface of the body;a layer of 3C-SiC on the top surface of the body;a layer of silicon on the layer of 3C-SiC;an ohmic contact extending through layer of 3C-SiC and the layer of silicon and contacting the implanted region;an anode metalization on the ohmic contact and corresponding to an anode of a Schottky diode; anda cathode metalization below the body and corresponding to a cathode of the Schottky diode.

20. The electronic device of claim 19, comprising a protection ring of the second conductivity type extending downward from the top surface of the body and laterally surrounding the implanted region.