US 11,810,783 B2
Gallium nitride semiconductor device and method for manufacturing the same
Chiaki Sasaoka, Nagoya (JP); Jun Kojima, Nagoya (JP); Shoichi Onda, Nagoya (JP); Masatake Nagaya, Kariya (JP); Kazukuni Hara, Kariya (JP); and Daisuke Kawaguchi, Hamamatsu (JP)
Assigned to DENSO CORPORATION, Kariya (JP); HAMAMATSU PHOTONICS K.K., Hamamatsu (JP); and National University Corporation Tokai National Higher Education and Research System, Nagoya (JP)
Filed by DENSO CORPORATION, Kariya (JP); HAMAMATSU PHOTONICS K.K., Hamamatsu (JP); and National University Corporation Tokai National Higher Education and Research System, Nagoya (JP)
Filed on Apr. 13, 2021, as Appl. No. 17/229,141.
Claims priority of application No. 2020-073158 (JP), filed on Apr. 15, 2020.
Prior Publication US 2021/0327710 A1, Oct. 21, 2021
Int. Cl. H01L 33/00 (2010.01); H01L 21/02 (2006.01); H01L 29/20 (2006.01); H01L 29/45 (2006.01); H01L 29/40 (2006.01); H01L 21/306 (2006.01)
CPC H01L 21/02389 (2013.01) [H01L 21/0254 (2013.01); H01L 21/02694 (2013.01); H01L 21/30625 (2013.01); H01L 29/2003 (2013.01); H01L 29/401 (2013.01); H01L 29/454 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A gallium nitride semiconductor device comprising:
a chip formation substrate made of gallium nitride and having one surface and an other surface opposite to the one surface;
a one surface side element component disposed on the one surface and providing a component of an one surface side of a semiconductor element; and
a metal film constituting a back surface electrode in contact with the other surface, wherein:
the other surface has an irregularity provided by
a plurality of convex portions with a trapezoidal cross section and
a plurality of concave portions located between the convex portions;
an upper base surface of the trapezoidal cross section in each of the plurality of convex portions is opposed to the one surface; and
a maximum depth of some of the concave portions vary.