Symmetric P-n-P InAlAs/InGaAs double-heterojunction bipolar transistors fabricated with Si-ion implantation

The authors have successfully fabricated symmetric P-n-P InAlAs/InGaAs double-heterojunction bipolar transistors (DHBTs) using self-aligned Si-ion implantation and refractory emitter contacts with current gains of 115 and 30 in the emitter-up and the emitter-down configurations, respectively. Two thin Be-doped In/sub 0.53/Ga/sub 0.47/As layers inserted on both sides of base lead to the excellent I-V characteristics. The authors have shown that hole injection from the external portions of the emitter should be suppressed by a factor of 10/sup -5/ to 10/sup -3/ at a collector current density of about 10/sup 3/ A/cm/sup 2/, which is much smaller than that of N-p-n GaAs/AlGaAs HBTs and DHBTs are promising devices for applications to circuits with low power dissipation.<>