Summary: 118 IEEE ELECTRON DEVICE LETTERS, VOL. 19, NO. 4, APRIL 1998
Submicron Self-Aligned HBT's
by Selective Emitter Regrowth
S. H. Park, T. P. Chin, Q. Z. Liu, S. L. Fu, T. Nakamura, P. K. L. Yu, and P. M. Asbeck, Senior Member, IEEE
Abstract--Fabrication of fully self-aligned heterojunction bipo-
lar transistors (HBT's) by selective emitter regrowth is described.
Scaled devices with emitter dimensions as small as 0:4 2 7 m2
demonstrate current gain up to 29, with successful suppression
of surface recombination effects. The RF characteristics of a
1:4 2 11 m2
device exhibited fT and fMAX of 75 and 46 GHz,
respectively, and is limited by the refractory base metallization.
This technology is promising for scaled HBT applications where
high-speed and low-power dissipation are critical.
THE scaling of heterojunction bipolar transistor (HBT)
device dimensions vertically and laterally is a key re-
search objective . The well-known HBT advantages of high
switching speed and current drive capability make them the
choice for a variety of high-performance circuit applications.