High-speed GaAlAs-GaAs heterojunction bipolar transistors with near-ballistic operation

Abstract

GaAlAs-GaAs heterojunction bipolar transistors (HBTs) with an abrupt emitter-base interface have been realised by molecular-beam epitaxy (MBE) on semi-insulating substrates. A gain-bandwidth product FT of 15 GHz has been measured for Ic = 20 mA and VCE = 8 V. These results are the best reported so far for HBTs and are very promising for high-speed logic.