Title :
An (Al,Ga)As/GaAs heterostructure bipolar transistor with nonalloyed graded-gap ohmic contacts to the base and emitter
Author :
Rao, M.A. ; Caine, E.J. ; Long, Stephen I. ; Kroemer, Herbert
Author_Institution :
University of California, Santa Barbara, CA
fDate :
1/1/1987 12:00:00 AM
Abstract :
Graded regions of n-(Ga,In)As and p-Ga(As,Sb) were incorporated side-by-side as emitter and base contacts, respectively, into an n-p-n (Al,Ga)As/GaAs heterostructure bipolar transistor (HBT). The process involved two separate molecular beam epitaxy (MBE) growths, leading to base contact regions that were self-aligned to the emitter mesas. The devices could be easily probed with pressure contacts even prior to any metallization, and excellent characteristics were obtained after final metallization. Contact resistivities of 5 × 10-7and 3 × 10-6Ω.cm2were measured for n- and p-type graded-gap ohmic contact structures, respectively.
Keywords :
Bipolar transistors; Conductivity; Gallium arsenide; Heterojunction bipolar transistors; Lead; Metallization; Molecular beam epitaxial growth; Ohmic contacts; Substrates; Temperature;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/EDL.1987.26540