In:
Japanese Journal of Applied Physics, IOP Publishing, Vol. 30, No. 8R ( 1991-08-01), p. 1659-
Abstract:
Collector-top Ge/GaAs heterojunction bipolar transistors (HBTs), consisting of an n -type GaAs emitter, a p -type Ge base, and an n -type Ge collector, are fabricated successfully. These exhibit a current gain of 430, the largest among reported collector-top HBTs. Ga atom diffusion into the Ge base layer from the surface of the GaAs emitter layer is suppressed using a two-step Ge growth process, wherein a thin Ge film is grown on GaAs at lower growth temperature prior to normal Ge growth at 500°C. For HBTs with low-temperature-grown (LTG) Ge films of 150 Å thickness, the current gain increases monotonically from 45 to 430 with decreasing LTG film growth temperature from 500°C to 150°C. Insertion of an LTG Ge film lowers the total amount of Ga atoms diffused from the Ge/GaAs heterointerface by one order of magnitude, and reduces both the base width and the doping density of the base layer, resulting in an increase in current gain.
Type of Medium:
Online Resource
ISSN:
0021-4922
,
1347-4065
DOI:
10.1143/JJAP.30.1659
Language:
Unknown
Publisher:
IOP Publishing
Publication Date:
1991
detail.hit.zdb_id:
218223-3
detail.hit.zdb_id:
797294-5
detail.hit.zdb_id:
2006801-3
detail.hit.zdb_id:
797295-7
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