US 12,348,154 B2
Switching device
Yuki Nakano, Kyoto (JP); and Hiroyuki Sakairi, Kyoto (JP)
Assigned to ROHM CO., LTD., Kyoto (JP)
Filed by ROHM CO., LTD., Kyoto (JP)
Filed on Sep. 8, 2023, as Appl. No. 18/463,318.
Application 15/225,877 is a division of application No. 14/804,920, filed on Jul. 21, 2015, granted, now 9,437,592, issued on Sep. 6, 2016.
Application 14/804,920 is a division of application No. 13/917,998, filed on Jun. 14, 2013, granted, now 9,117,800, issued on Aug. 25, 2015.
Application 18/463,318 is a continuation of application No. 17/959,859, filed on Oct. 4, 2022, granted, now 11,784,580.
Application 17/959,859 is a continuation of application No. 17/228,020, filed on Apr. 12, 2021, granted, now 11,509,240, issued on Nov. 22, 2022.
Application 17/228,020 is a continuation of application No. 16/811,676, filed on Mar. 6, 2020, granted, now 11,005,387, issued on May 11, 2021.
Application 16/811,676 is a continuation of application No. 16/397,134, filed on Apr. 29, 2019, granted, now 10,630,199, issued on Apr. 21, 2020.
Application 16/397,134 is a continuation of application No. 15/853,101, filed on Dec. 22, 2017, granted, now 10,320,309, issued on Jun. 11, 2019.
Application 15/853,101 is a continuation of application No. 15/225,877, filed on Aug. 2, 2016, granted, now 9,866,143, issued on Jan. 9, 2018.
Prior Publication US 2023/0421073 A1, Dec. 28, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H02M 7/44 (2006.01); H10D 30/60 (2025.01); H10D 30/66 (2025.01); H10D 62/17 (2025.01); H10D 62/83 (2025.01); H10D 62/832 (2025.01); H10D 64/23 (2025.01); H10D 64/27 (2025.01); H10D 64/60 (2025.01); H10D 64/62 (2025.01); H10D 84/00 (2025.01); H10D 89/60 (2025.01)
CPC H02M 7/44 (2013.01) [H10D 30/60 (2025.01); H10D 30/668 (2025.01); H10D 62/393 (2025.01); H10D 62/83 (2025.01); H10D 62/8325 (2025.01); H10D 64/256 (2025.01); H10D 64/513 (2025.01); H10D 64/605 (2025.01); H10D 64/62 (2025.01); H10D 84/141 (2025.01); H10D 89/911 (2025.01); H10D 64/516 (2025.01)] 6 Claims
OG exemplary drawing
 
1. A wide band gap semiconductor device comprising:
a semiconductor layer having a first surface and a second surface opposite with the first surface, the first surface including a gate trench of a stripe shape and the semiconductor layer including an SiC semiconductor layer;
a first electrode above the first surface;
a second electrode beneath the second surface;
a gate insulating film in the gate trench;
a third electrode in the gate trench via the gate insulting film;
a thin electrode layer between the first electrode and the semiconductor layer, the thin electrode layer including a titanium-based material;
an insulating film over a gate electrode, the insulating film including SiO2; and
a p-type impurity contact region in the semiconductor layer through which the p-type impurity region is electrically connected to the first electrode, wherein
the semiconductor layer comprises:
a source region at the first surface proximate a top end of the gate trench;
a p-type impurity region that extends to the second surface from the first surface,
a bottom part of the p-type impurity region being deeper than a bottom of the gate trench, and
an n-type impurity region beneath the gate trench and the p-type impurity region,
the gate trench includes a curved portion around the bottom of the gate trench,
a thickness of the semiconductor layer is between 30 um and 400 um,
the first electrode includes aluminum,
the deepest part of the p-type impurity region is in a vicinity of an area directly below the p-type impurity contact region in a thickness direction of the semiconductor layer,
the gate trench is in contact with the n-type impurity region,
the gate trench spreads outward at the first surface, in a cross-sectional view.