The annealing condition dependence of the electrical and optical properties
in C-doped InGaAs lattice-matched to InP is investigated in detail. It is
revealed that hole concentration increases with annealing time at annealing
temperatures between 450 degrees C and 550 degrees C due to hydrogen remov
al from epilayers. The annealing time for obtaining the maximam hole concen
tration is shown to become shorter with higher annealing temperature. It is
also found that C accepters are deactivated by annealing at 550 degrees C
for more than 5 min, resulting in a decrease of hole concentration, mobilit
y and photoluminescense intensity. These deteriorations in both the electri
cal and optical quality of C-doped InGaAs might be caused by the transforma
tion of C accepters to C donors (on group-III sites) or interstitial C atom
s. The optimum annealing condition was applied for the fabrication of InP/I
nGaAs heterojunction bipolar transistors, and the good characteristics are
successfully demonstrated. (C) 1998 Elsevier Science B.V. All rights reserv
ed.