Structural optimization of InGaP/GaAs HBT for power amplifier applications

We devised a dual emitter structure (IB2E) of InGaP/GaAs HBT for MMIC power amplifier application, fabricated that with a standard 2 mum emitter-width process, and analyze the performance in the aspect of thermal limitation and power density compared to conventionally used structure (2BIE). The structure composed of I base with 2 surrounding emitter fingers (IB2E) has been simulated to have several advantages in thermal behavior and high power application. Thermal distribution analysis reveals that one unit cell of IB2E has lower value of maximum temperature under the emitter electrode than that for the unit cell of 2BIE by 14 K Measured current gain falloff of the 1B2E was less than the 2BIE by 1.41 times, and does not show any current gain collapse in the array structure for high power application.