Engineering on npn algaas heterojunction bipolar transistors
Journal
Proceedings of SPIE - The International Society for Optical Engineering
Journal Volume
797
Pages
357-362
Date Issued
1987
Author(s)
Abstract
Two device structures are presented which could solve two problems that an AlGaAs heterojunction bipolar transistor faces when it is used in GaAs integrated circuits. The first is the 2kT surface recombination current problem which seriously reduces the current gain as the device area becomes sufficiently small. It is found that by sandwiching a high bandgap P-type AlGaAs in the emitter-base junction interface, the 2kT current could be substantially reduced and the current gain displays flattened characteristics at low collector current (<1 μA). The second problem is how to reliably smooth out the potential spike at the base-collector interface which results in a serious reach-through phenomenon in the common emitter I-V characteristics of the transistors. It is found that by adding a thin spacer layer with the same composition but the opposite type as the base layer in the base-collector junction interface, the potential spike can be easily and reproducibly suppressed. © 1987 SPIE.
SDGs
Type
journal article