GaAsP/InGaP heterojunction bipolar transistors grown by MOCVD

TitleGaAsP/InGaP heterojunction bipolar transistors grown by MOCVD
Publication TypeJournal Article
Year of Publication2017
AuthorsHeidelberger, C, Fitzgerald, EA
JournalJournal of Applied Physics
Volume121
Issue4
Pagination045703
Date Published2017/01/28/
ISBN Number0021-8979
Keywordschemical-vapor-deposition, gaas, ingap
Abstract

Heterojunction bipolar transistors with GaAsxP1-x bases and collectors and InyGa1-yP emitters were grown on GaAs substrates via metalorganic chemical vapor deposition, fabricated using conventional techniques, and electrically tested. Four different GaAsxP1-x compositions were used, ranging from x = 0.825 to x = 1 (GaAs), while the InyGa1-yP composition was adjusted to remain lattice-matched to the GaAsP. DC gain close to or exceeding 100 is measured for 60 mu m diameter devices of all compositions. Physical mechanisms governing base current and therefore current gain are investigated. The collector current is determined not to be affected by the barrier caused by the conduction band offset between the InGaP emitter and GaAsP base. While the collector current for the GaAs/InGaP devices is well-predicted by diffusion of electrons across the quasi-neutral base, the collector current of the GaAsP/InGaP devices exceeds this estimate by an order of magnitude. This results in higher transconductance for GaAsP/InGaP than would be estimated from known material properties. Published by AIP Publishing.

Short TitleJ. Appl. Phys.