Effect of phosphorus gettering on 1/ƒ noise in bipolar transistors

Phosphorus silicate glass gettering has been applied to silicon npn planar transistors fabricated in IC technology in order to reduce 1/? noise by removing metal impurities out of the base-emitter region. It is found that gettered transistors show significantly reduced 1/? noise power as well as lowered recombination current of the emitter-base junction. Furthermore the noise power spectrum becomes structured and is no longer strictly of the pure 1/? type, as is typical for ungettered devices. The results suggest a close relationship between 1/? noise and recombination processes.