US 12,142,672 B2
Heterojunction bipolar transistor and manufacturing method of the same
Takuya Hoshi, Tokyo (JP); Yuki Yoshiya, Tokyo (JP); Yuta Shiratori, Tokyo (JP); Hiroki Sugiyama, Tokyo (JP); Minoru Ida, Tokyo (JP); and Hideaki Matsuzaki, Tokyo (JP)
Assigned to Nippon Telegraph and Telephone Corporation, Tokyo (JP)
Appl. No. 17/612,463
Filed by Nippon Telegraph and Telephone Corporation, Tokyo (JP)
PCT Filed May 29, 2019, PCT No. PCT/JP2019/021213
§ 371(c)(1), (2) Date Nov. 18, 2021,
PCT Pub. No. WO2020/240725, PCT Pub. Date Dec. 3, 2020.
Prior Publication US 2022/0208998 A1, Jun. 30, 2022
Int. Cl. H01L 29/737 (2006.01); H01L 21/02 (2006.01); H01L 29/66 (2006.01)
CPC H01L 29/737 (2013.01) [H01L 21/0254 (2013.01); H01L 29/66318 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for producing a heterojunction bipolar transistor, the method comprising:
a first step of crystal-growing, over a first substrate in a following order with a main surface as a Group III polar surface,
an emitter contact layer comprising a nitride semiconductor that is made n-type,
an emitter layer comprising a nitride semiconductor having a bandgap larger than that of the nitride semiconductor of the emitter contact layer,
a base layer comprising an undoped nitride semiconductor having a bandgap smaller than that of the nitride semiconductor of the emitter layer,
a p-type base layer comprising the same nitride semiconductor as that of the base layer and made p-type,
a collector layer comprising a nitride semiconductor that has the same bandgap as that of the nitride semiconductor of the p-type base layer and that is made n-type, and
a sub-collector layer comprising the same nitride semiconductor as that of the collector layer and made n-type;
a second step of bonding the first substrate and a second substrate;
a third step of removing the first substrate to create a state in which the sub-collector layer, the collector layer, the p-type base layer, the base layer, the emitter layer, and the emitter contact layer are formed over the second substrate in this order with the main surface as a Group V polar surface;
a fourth step of patterning the emitter contact layer into a mesa shape;
a fifth step of forming a base electrode that is ohmic-connected to the p-type base layer on the emitter layer on a side of the mesa-shaped emitter contact layer; and
a sixth step of forming an emitter electrode on the mesa-shaped emitter contact layer.