Influence of Emitter-Edge-Thinning Thickness on the Heterojunction Bipolar Transistor Performance

Abstract

In this work, the characteristics of the InGaP/GaAs heterojunction bipolar transistors with different emitter-edge-thinning thickness were systematically investigated. A stronger downward-band-bending phenomenon was observed at the edge of emitter-edgethinning intersection with the exposed base surface. This band bending induced the presence of a potential saddle point, which substantially increased the recombination rates and electron densities. In addition, the decision of emitter-edge-thinning thickness plays a key role in reducing surface recombination at the potential saddle point. As the emitter-edge-thinning thickness was selected between 100 and 200 Å, the lowest recombination rate and electron density and highest dc current gain could be obtained. Furthermore, good agreements between the theoretical analyses and experimental results were found.

Comparative Studies on InGaP/GaAs Heterostructure-Emitter Bipolar Transistors with Tunneling- and Superlattice-Confinement Structures

“…GaAs-based heterojunction bipolar transistors (HBTs) have emerged to be one of the promising high-speed devices because of their expected potential based on high current gain, high current handing capability, and extremely high frequency performance. 1,2 Typically, a large base-emitter (B-E) turn-on voltage resulting from the heterojunction severely limits the minimum operated voltage and causes a large collector-emitter offset voltage (DV CE ), which increases the power consumption in circuit applications. 3,4 Some improved HBTs, such as heterostructure-emitter bipolar transistor (HEBTs), have been addressed to lower the energy band at the emitter side and reduce the DV CE value.…”