Schottky diode with reduced forward voltage

• US 9,859,383 B2
• Filed: 11/20/2014
• Issued: 01/02/2018
• Est. Priority Date: 11/26/2013
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Konrath, Jens Peter, Rupp, Roland, Schulze, Hans-Joachim
• Primary Examiner(s): Toledo, Fernando L
• Assistant Examiner(s): PRASAD, NEIL R
• Application Number:
  US14/548,709
• Publication Number:
  US 20150144966A1
• Time in Patent Office: 1,139 Days
• CPC Class Codes: H01L 29/1608 Silicon carbide
• CPC Class Codes: H01L 29/36 characterised by the concentration or distribution of impurities in the bulk material within semiconductor regions H01L29/06
• CPC Class Codes: H01L 29/66143 Schottky diodes
• CPC Class Codes: H01L 29/872 Schottky diodes

Abstract

A semiconductor component includes a semiconductor body of a first conduction type and a metal layer on the semiconductor body, wherein the metal layer forms with the semiconductor body a Schottky contact along a contact surface. A doping concentration of the first conduction type on the contact surface varies along a direction of the contact surface.

Claims

1. A semiconductor component, comprising:

a semiconductor body of a first conduction type that comprises a drift zone; and

a metal layer on the semiconductor body, wherein the metal layer forms with the semiconductor body a Schottky contact along a contact surface,

wherein a doping concentration of the first conduction type on the contact surface varies along a direction of the contact surface in such a way as to define a multiplicity of more heavily doped regions spaced apart from one another along the contact surface by a plurality of more weakly doped regions, wherein the multiplicity of more heavily doped regions have heavier doping than the drift zone of the semiconductor component and the plurality of more weakly doped regions, wherein both the more weakly doped regions and the more heavily doped regions have an excess of free charge carriers of the first conduction type.

2. The semiconductor component as claimed in claim 1, wherein the doping concentration of the first conduction type on the contact surface varies stepwise along a direction of the contact surface.

3. The semiconductor component as claimed in claim 1, wherein the doping concentration of the first conduction type on the contact surface varies continuously along a direction of the contact surface.

4. The semiconductor component as claimed in claim 2, wherein between at least two of the more heavily doped regions the contact surface has a doping concentration which corresponds to a doping concentration of the drift zone of the semiconductor body.

5. The semiconductor component as claimed in claim 1, wherein the at least one more heavily doped region has a depth of approximately 1 μ

m or less in a direction perpendicular to the contact surface.

6. The semiconductor component as claimed in claim 1, wherein the semiconductor body comprises silicon carbide (SiC), and wherein the at least one more heavily doped region has a depth of approximately 100 nm or less in a direction perpendicular to the contact surface.

7. The semiconductor component as claimed in claim 1, furthermore comprising at least one region of a second conduction type on the contact surface.

8. The semiconductor component as claimed in claim 7, wherein the region of the second conduction type has a greater depth in a direction perpendicular to the contact surface than the at least one more heavily doped region has.

9. The semiconductor component as claimed in claim 7, wherein the at least one more heavily doped region is arranged in an intermediate space between two regions of the second conduction type, and the lateral extent of the at least one more heavily doped region comprises less than ⅓

of the intermediate space.

10. The semiconductor component as claimed in claim 1, furthermore comprising at least one buried region of a second conduction type, which is buried in the semiconductor body.

11. The semiconductor component as claimed in claim 1, wherein the metal layer for forming the Schottky contact comprises at least one of Au, Pt, Cu, Ni, Ti, TiW, Mo, Ti_xN_y, Mo_xN_y, Pd, Mn, Al, Ag.

12. A semiconductor component, comprising:

a semiconductor body of a first conduction type;

a metal layer on the semiconductor body, wherein the metal layer forms with the semiconductor body a Schottky contact along a contact surface;

at least one region of a second conduction type on the contact surface, and

a plurality of regions with increased doping concentration of the first conduction type spaced apart from one another along the contact surface by a plurality of regions with decreased doping concentration, in which the doping concentration of the plurality of regions with increased doping concentration is greater than a doping concentration of the semiconductor body and a doping concentration of the regions with decreased doping concentration, wherein both the plurality of regions with increased doping concentration and the plurality of regions with decreased doping concentration have an excess of free charge carriers of the first conduction type.

13. The semiconductor component as claimed in claim 12, wherein the region of the second conduction type and the region on the contact surface, in which the doping concentration of the first conduction type is greater than a doping concentration of the semiconductor body, are arranged on the contact surface.

14. The semiconductor component as claimed in claim 13, wherein the doping concentration of the first conduction type on the contact surface varies stepwise along a direction of the contact surface to define the plurality of regions.

15. The semiconductor component as claimed in claim 13, wherein the doping concentration of the first conduction type on the contact surface varies continuously along a direction of the contact surface to define the plurality of regions.

16. The semiconductor component as claimed in claim 13, wherein the metal layer for forming the Schottky contact comprises at least one of Au, Pt, Cu, Ni, Ti, TiW, Mo, Ti_xN_y, Mo_xN_y, Pd, Mn, Al, Ag.

17. A semiconductor component, comprising:

a semiconductor body of a first conduction type that comprises a drift zone; and

a metal layer on the semiconductor body, wherein the metal layer forms with the semiconductor body a Schottky contact along a contact surface,

wherein a doping concentration of the first conduction type along the contact surface is greater than an underlying portion of the drift zone, and wherein the dopant concentration along the contact surface varies along a direction of the contact surface, and

wherein the doping concentration along the direction of the contact surface varies in such a way as to define a multiplicity of more heavily doped regions, which have heavier doping than neighboring regions at the contact surface and have heavier doping than the drift zone of the semiconductor component, wherein both the more heavily doped regions and the neighboring regions have an excess of free charge carriers of the first conduction type.