Silicon carbide semiconductor device and method of manufacturing the same

• US 8,941,122 B2
• Filed: 04/02/2013
• Issued: 01/27/2015
• Est. Priority Date: 04/03/2012
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kawai, Jun, Tokura, Norihito, Sugiura, Kazuhiko
• Primary Examiner(s): Nguyen, Cuong Q
• Assistant Examiner(s): Gebreyesus, Yosef
• Application Number:
  US13/855,072
• Publication Number:
  US 20130285070A1
• Time in Patent Office: 665 Days
• Field of Search: 257/77, 257/302, 257/E29.189, 257/E27.054, 257/E27.096, 257/E29.318, 257/E29.262, 257/E21.41
• US Class Current: 257/77
• CPC Class Codes: H01L 21/0455 Making n or p doped regions or layers, e.g. using diffusion
• CPC Class Codes: H01L 21/0485 Ohmic electrodes
• CPC Class Codes: H01L 21/22 Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities
• CPC Class Codes: H01L 29/1608 Silicon carbide
• 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 29/7827 Vertical transistors H01L29/7802, H01L29/78642 take precedence

Abstract

In a manufacturing method of a silicon carbide semiconductor device, a semiconductor substrate made of single crystal silicon carbide is prepared. At a portion of the semiconductor substrate where a first electrode is to be formed, a metal thin film made of electrode material including an impurity is formed. After the metal thin film is formed, the first electrode including a metal reaction layer in which the impurity is introduced is formed by irradiating the metal thin film with a laser light.

Claims

1. A silicon carbide semiconductor device comprising:

a semiconductor layer that has a main surface and a rear surface being an opposite surface of the main surface and is made of single crystal silicon carbide; and

a first electrode that forms an ohmic junction with the semiconductor substrate,

wherein a junction portion of the first electrode with the semiconductor substrate is formed of a metal reaction layer in which an impurity included in the first electrode is introduced and a metal atom that forms the first electrode reacts with at least one of carbon or silicon that forms the semiconductor substrate, and

wherein, in the metal reaction layer, a diffusion depth of the impurity and a diffusion depth of the metal atom are the same.