InGaP/GaAs0.57P0.28Sb0.15/GaAs double HBT with weakly type-II base/collector junction
Journal
IEEE Electron Device Letters
Journal Volume
33
Journal Issue
4
Pages
489-491
Date Issued
2012-04
Author(s)
Abstract
We report on the dc characteristics of an InGaP/ GaAs 0.57 P 0.28 Sb 0.15 /GaAs double heterojunction bipolar transistor (DHBT). In comparison with control InGaP/GaAs single heterojunction bipolar transistors (SHBTs), the DHBT shows a lower turn-on voltage (V BE, on ) by ~ 70 mV, a lower knee voltage up to J c ~ 40 kA/cm 2 , and less temperature-sensitive current gain. The validity of reciprocity in the Gummel plot suggests no potential spikes at the emitter/base and base/collector (BC) junctions of the DHBT. By considering the differences, in terms of the built-in voltage of the BC junction, the Fermi level in the base, and the renormalized energy gap of the base, between the GaAsPSb DHBT and the control InGaP/GaAs SHBT, we conclude that the heavily p-doped GaAs 0.57 P 0.28 Sb 0.15 base and the lightly n-doped GaAs collector are in weakly type-II band alignment with a conduction and valence band offset of 44 and 221 meV, respectively. These findings indicate that GaAsPSb is a promising base material for DHBTs operating at high temperature and low V BE, on conditions without suffering from the collector current blocking.
Type
journal article