Influence of geometry and passivation on noise in GaInP/GaAs heterojunction bipolar transistors

First order and low-frequency noise generated by GaInP/GaAs heterojunction bipolar transistors were measured. Passivated transistors had higher gain values. Noise was measured in the 1 Hz to 100 kHz frequency range on common-emitter-mounted transistors. The 1/f component was examined and the emitter series resistances were obtained. The nearness of the base contact on the smaller devices resulted in a higher noise level because of increased recombinations.