US 11,990,543 B2
Power transistor with soft recovery body diode
Kijeong Han, Apex, NC (US); Sei-Hyung Ryu, Cary, NC (US); and Daniel Jenner Lichtenwalner, Raleigh, NC (US)
Assigned to Wolfspeed, Inc., Durham, NC (US)
Filed by Wolfspeed, Inc., Durham, NC (US)
Filed on Mar. 22, 2021, as Appl. No. 17/208,271.
Application 17/208,271 is a continuation in part of application No. 17/110,027, filed on Dec. 2, 2020.
Prior Publication US 2022/0173238 A1, Jun. 2, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H01L 29/78 (2006.01); H01L 29/16 (2006.01)
CPC H01L 29/7805 (2013.01) [H01L 29/1608 (2013.01)] 31 Claims
OG exemplary drawing
 
1. A semiconductor device comprising:
a substrate;
a drift layer on the substrate, the drift layer having a minority carrier lifetime between 1 μs and 20 μs; and
one or more implanted regions in the drift layer, the one or more implanted regions configured to:
provide a vertical transistor device configured to conduct current in a first direction; and
provide a body diode configured to conduct current in a second direction opposite the first direction,
wherein the drift layer has a first doping type and a first doping concentration;
wherein the one or more implanted regions comprise a body well having a second doping type opposite the first doping type and a second doping concentration; and
wherein the first and second doping concentrations and a thickness of the drift layer are configured so that a softness factor of the body diode is between 0.5 and 10.