A new emitter design of InGaP/GaAs HBTs for high-frequency applications

An HBT (heterojunction bipolar transistor) structure using an AlGaAs-InGaP emitter is proposed. The AlGaAs-InGaP configuration introduces an electron launcher in the emitter and makes use of the velocity overshoot effect. This enhances the emitter transport and reduces the electron accumulation in the emitter. Simulations show that, by using the AlGaAs-InGaP structure, the emitter charging time can be greatly reduced compared to the conventional AlGaAs emitter design. As a result, the cutoff frequency can be substantially increased. A cutoff frequency of 235 GHz has been predicted.<
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