Silicon-germanium Single-heterojunction Bipolar Transistor

G.M. Khanduri; B.S. Panwar

doi:10.14429/dsj.56.1891

G.M. Khanduri Indian Institute of Technology Delhi, New Delhi
B.S. Panwar Indian Institute of Technology Delhi, New Delhi

DOI: https://doi.org/10.14429/dsj.56.1891

Keywords: Single-heterojunction bipolar transistor, simulation, double-heterojunction bipolar transistor, SiGe SHBT, cutoff frequency SiGe technology, SiGe DHBT

Abstract

The cutoff frequency performance of an NPN Si/SiGe/SiGe single-heterojunction bipolar
transistor (SiGe SHBT) at high collector current densities has been analysed using a 2-D MEDICI
device simulator. A conventional NPN Si/SiGe/Si double-heterojunction bipolar transistor
(SiGe DHBT) having uniform 20 atomic per cent of germanium in the base region has been
investigated for comparison. The analysis shows the formation of a retarding potential barrier
for minority carrier electrons at the base-collector heterojunction of the DHBT structure. Whereas,
the base-collector homojunction of the SiGe SHBT structure, having a uniform 15 atomic per
cent of germanium profile in its base and collector, inhibits the formation of such a retarding
potential barrier, the SHBT structure with a base-collector homojunction shows an improved
cutoff frequency at high collector current density in comparison with conventional SiGe DHBT,
which makes it more promising for high speed, scaled down, field-specific applications.