Semiconductor devices with heterojunction barrier regions and methods of fabricating same

• US 9,595,618 B2
• Filed: 09/29/2014
• Issued: 03/14/2017
• Est. Priority Date: 03/08/2010
• Status: Active Grant

• Current Assignee: Wolfspeed, Inc.
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Zhang, Qingchun
• Primary Examiner(s): Kraig, William F
• Assistant Examiner(s): Kim, Sun M
• Application Number:
  US14/499,390
• Publication Number:
  US 20150076522A1
• Time in Patent Office: 897 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 29/0619 with a supplementary region doped oppositely to or in rectifying contact with the semiconductor containing or contacting region, e.g. guard rings with PN or Schottky junction
• 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 29/47 Schottky barrier electrodes H01L29/435 takes precedence
• CPC Class Codes: H01L 29/6606 the devices being controllable only by variation of the electric current supplied or the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched, e.g. two-terminal devices
• 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 29/861 Diodes
• CPC Class Codes: H01L 29/872 Schottky diodes

Abstract

An electronic device includes a silicon carbide layer including an n-type drift region therein, a contact forming a junction, such as a Schottky junction, with the drift region, and a p-type junction barrier region on the silicon carbide layer. The p-type junction barrier region includes a p-type polysilicon region forming a P-N heterojunction with the drift region, and the p-type junction barrier region is electrically connected to the contact. Related methods are also disclosed.

Claims

1. A Schottky diode comprising:

a drift layer having a first surface associated with an active region and an edge termination region substantially laterally adjacent the active region, wherein the drift layer comprises silicon carbide and is doped with a doping material of a first conductivity type and the edge termination region has an edge termination recess extending into the drift layer from the first surface;

a Schottky layer over the active region of the first surface to form a Schottky junction;

an edge termination structure formed in a bottom surface of the edge termination recess, wherein the edge termination structure comprises;

a first guard ring; and

a second guard ring;

an array of junction barrier elements formed below the Schottky junction and in the drift layer; and

an implanted region, wherein one of the first and second guard rings is only partially disposed within the implanted region and the other of the first and second guard rings is completely disposed within the implanted region.

2. The Schottky diode of claim 1 wherein the first surface of the drift layer comprises a plurality of junction barrier element recesses in the active region such that at least certain junction barrier elements of the array of junction barrier elements are doped regions that extend into the drift layer about corresponding ones of the plurality of junction barrier element recesses, and the doped regions are doped with a doping material of a second conductivity type, which is opposite the first conductivity type.

3. The Schottky diode of claim 1 wherein the edge termination recess extends substantially about the active region.

4. The Schottky diode of claim 1 wherein the Schottky layer is formed from a low barrier height capable metal that comprises at least one of a group consisting of titanium, chromium, and aluminum.

5. The Schottky diode of claim 1 wherein each junction barrier element of the array of junction barrier elements is substantially the same as others of the array of junction barrier elements.

6. The Schottky diode of claim 1 wherein at least a first junction barrier element of the array of junction barrier elements is substantially different in size or shape than at least a second junction barrier element of the array of junction barrier elements.

7. The Schottky diode of claim 1 wherein at least certain junction barrier elements in the array of junction barrier elements are elongated stripes.

8. The Schottky diode of claim 1 wherein at least certain junction barrier elements in the array of junction barrier elements are substantially around the first surface.