Patent ID: 6271098
Filing Date: 2001-08-07
Classification: H01L

Abstract:
A method for producing a heterojunction bipolar transistor which comprises steps of:forming a first conductivity type GaAs collector substrate;laminating a second conductivity type GaAs base region, and an emitter region which includes at least a first conductivity type AlGaAs layer, a first conductivity type GaAs carrier supply layer formed on the first conductivity type AlGaAs layer, and a first conductivity type GaAs ballast resistor layer formed on the first conductivity type GaAs carrier supply layer, on the first conductivity type GaAs collector substrate;forming a emitter electrode on the emitter region;etching the emitter region until the base region is exposed by using the emitter electrode as a mask, thereby forming emitter mesa portions; andproviding a base electrode on the base region and a collector electrode on the collector region, respectively.