An Indium-Free MBE Growth of AlGaAs/GaAs HBTs

概要

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MBE grown AlGaAs/GaAs HBTs were fabricated using direct-radiation substrate heating. The behavior of the current gain distribution in wafers was investigated, and the variation was found to reflect the substrate temperature distributions. The decrement in the current gain is caused by an increment of generation-recombination current in the EB junction due to a low substrate temperature. Be diffusion from the base layer into the emitter layer also deteriorates the emitter injection efficiency when an undoped spacer layer inserted between the emitter and base layers is not sufficiently thick. Consequently, it is pointed out that a uniform substrate temperature distribution and a low substrate temperature with a thin undoped spacer layer are desirable. A very uniform current gain (higher than 80) was obtained for a HBT with a 4×10^<19>/cm^3 base doping at a collector current density of 1×10^3 A/cm^2.
社団法人応用物理学会の論文
1987-03-20