US 12,148,825 B2
Methods of reducing the electrical and thermal resistance of SiC substrates and device made thereby
James Albert Cooper, Jr., Santa Fe, NM (US)
Assigned to Purdue Research Foundation, West Lafayette, IN (US)
Filed by Purdue Research Foundation, West Lafayette, IN (US)
Filed on Dec. 29, 2020, as Appl. No. 17/136,457.
Application 17/136,457 is a continuation of application No. 16/704,720, filed on Dec. 5, 2019, granted, now 10,879,388.
Application 16/704,720 is a continuation of application No. 15/722,820, filed on Oct. 2, 2017, granted, now 10,505,035, issued on Dec. 10, 2019.
Application 15/722,820 is a continuation of application No. 15/057,055, filed on Feb. 29, 2016, granted, now 9,780,206, issued on Oct. 3, 2017.
Claims priority of provisional application 62/121,916, filed on Feb. 27, 2015.
Prior Publication US 2021/0119042 A1, Apr. 22, 2021
Int. Cl. H01L 29/78 (2006.01); H01L 21/04 (2006.01); H01L 29/06 (2006.01); H01L 29/08 (2006.01); H01L 29/10 (2006.01); H01L 29/16 (2006.01); H01L 29/417 (2006.01); H01L 29/45 (2006.01); H01L 29/66 (2006.01); H01L 29/739 (2006.01); H01L 29/872 (2006.01)
CPC H01L 29/7816 (2013.01) [H01L 21/0475 (2013.01); H01L 29/1079 (2013.01); H01L 29/1608 (2013.01); H01L 29/66068 (2013.01); H01L 29/7393 (2013.01); H01L 29/7395 (2013.01); H01L 29/872 (2013.01); H01L 29/45 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A power semiconductor device comprising a silicon carbide substrate having a first doping type and having at least a first layer or region formed above the substrate, the first layer or region having the first doping type, the silicon carbide substrate having a pattern of pits formed thereon, the device further comprising an ohmic metal disposed at least in the pits to form low-resistance ohmic contacts, each pit of the pattern of pits having a depth that extends short of the first layer, and wherein each portion of the substrate that defines a vertical path between one of the pattern of pits and the first layer or region has the first doping type.