InGaP/InGaAsN/GaAs NpN double heterojunction bipolar transistor

摘要

The authors have demonstrated a functional NpN double heterojunction bipolar transistor (DHBT) using InGaAsN for base layer. The InGaP/In(sub 0.03) Ga(sub 0.97)As(sub 0.99)N(sub 0.01)/GaAs DHBT has a low V(sub ON) of 0.81 V, which is 0.13 V lower than in a InGaP/GaAs HBT. The lower V(sub ON) is attributed to the smaller bandgap (E(sub g)=1.20eV) of MOCVD grown In(sub 0.03) Ga(sub 0.97)As(sub 0.99)N(sub 0.01) base layer. GaAs is used for the collector; thus the BV(sub CEO) is 10 V, consistent with the BV(sub CEO) of InGaP/GaAs Hbts of comparable collector thickness and doping level. To alleviate the current blocking phenomenon caused by the larger (triangle)E(sub C) between InGaAsN and GaAs, a graded InGaAs layer with (delta)-doping is inserted at the base-collector junction. The improved device has a peak current gain of 7 with ideal IV characteristics.