Structural optimization of InGaP/GaAs HBT for power amplifier applications

We devised a dual emitter structure (1B2E) of InGaP/GaAs HBT for MMIC power amplifier application, fabricated with a standard 2 /spl mu/m emitter-width process, and analyze the thermal limitation and power density performance compared to the conventionally used structure (2B1E). The structure, composed of 1 base with 2 surrounding emitter fingers (1B2E), has been simulated showing its several advantages in thermal behavior and it suitability for high power applications. Thermal distribution analysis reveals that one unit cell of 1B2E has a lower value of maximum temperature under the emitter electrode than that for the unit cell of 2B1E by 14 K. The measured current gain falloff of the 1B2E was less than the 2B1E by 1.41 times, and does not show any current gain collapse in the array structure for high power application.