US 12,284,823 B1
Buried field shield in III-V compound semiconductor trench MOSFETs via etch and regrowth
Andrew Binder, Albuquerque, NM (US); and James A. Cooper, Santa Fe, NM (US)
Assigned to National Technology & Engineering Solutions of Sandia, LLC, Albuquerque, NM (US); and James Cooper, Santa Fe, NM (US)
Filed by National Technology & Engineering Solutions of Sandia, LLC, Albuquerque, NM (US); and James A. Cooper, Santa Fe, NM (US)
Filed on Jun. 2, 2022, as Appl. No. 17/830,624.
Claims priority of provisional application 63/208,119, filed on Jun. 8, 2021.
Int. Cl. G01S 7/481 (2006.01); G01S 17/894 (2020.01); G03B 30/00 (2021.01); H01L 21/76 (2006.01); H01L 21/761 (2006.01); H04N 13/239 (2018.01); H04N 23/51 (2023.01); H04N 23/56 (2023.01); H04N 23/74 (2023.01); H10D 30/01 (2025.01); H10D 30/66 (2025.01); H10D 62/10 (2025.01); H10D 62/17 (2025.01); H10D 62/85 (2025.01)
CPC H10D 62/109 (2025.01) [H01L 21/7605 (2013.01); H01L 21/761 (2013.01); H10D 30/021 (2025.01); H10D 30/0297 (2025.01); H10D 30/668 (2025.01); H10D 62/393 (2025.01); H10D 62/8503 (2025.01)] 13 Claims
OG exemplary drawing
 
1. A III-V compound semiconductor trench MOSFET, comprising:
a substrate comprising a III-V compound semiconductor of a first conductivity type,
a drift layer comprising a III-V compound semiconductor of the first conductivity type on the substrate,
a body layer comprising a III-V compound semiconductor of a second conductivity type opposite the first conductivity type on the drift layer,
a source layer comprising a III-V compound semiconductor of the first conductivity type on the body layer,
a gate trench defined by sidewalls and a bottom formed through the source layer and the body layer that is embedded in and terminates in the drift layer,
a gate dielectric layer conformally lining the sidewalls and the bottom of the gate trench,
a buried field shield comprising a III-V compound semiconductor of the second conductivity type that is positioned at least partially below the bottom of the trench and is embedded in the drift layer, thereby forming a PN junction with the drift layer, wherein the buried field shield is electrically connected to the body layer and terminates at the source layer,
a drain contact to the substrate,
a gate contact that at least partially fills the gate trench on the gate dielectric layer,
a source contact to the source layer, and
a body contact made through the source layer and contacting the body layer.