Abstract: A washed emitter transistor was developed, whose emitter was formed by phosphorus diffusion through a thin layer of thermally grown oxide. Studies were made on DC characteristics, current gain vs. collector current, and current gain vs. temperature. The effects of surface recombination and bandgap narrowing in the emitter on the gain were investigated. The results show that the washed emitter transistor has a uniform gain within the range of five orders of magnitude of I_C and can work at a current as low as 1 nA. Compared with the conventional transistors, the minimum working current can be reduced by a factor of 10³ and the surface recombination velocity by a factor of 50%, and an increased yield of 20% can be achieved. The gain is less temperature dependent because of lighter bandgap narrowing in the emitter. It can be expected that the power dissipation of ICs will be considerably reduced if the washed emitter transistor is adopted.