Patent ID: 6861906

Claim:
A high-frequency semiconductor device, comprising: a first amplifier stage including first transistors, each having a first bipolar transistor of a heterojunction structure, an collector electrode output, and an emitter resistor having a resistance value of RE1 connected in series with an emitter electrode of the first bipolar transistor, said first transistors connected in parallel in a plural form and disposed on a first semiconductor substrate, said first amplifier stage configured to amplify an input signal and having a common output connected to each of said collector electrode outputs; and a second amplifier stage in series with the first amplifier stage and configured to amplify a signal outputted from the common output of said first amplifier stage and including second transistors each having a second bipolar transistor of a heterojunction structure and a base resistor having a resistance value of RB2 connected in series with a base electrode of the second bipolar transistor, said second transistors connected in parallel in a plural form and disposed on a second semiconductor substrate.