Low frequency noise in complementary npn and pnp polysilicon emitter bipolar junction transistors

Low frequency noise characteristics of high voltage, high performance compl ementary polysilicon emitter bipolar transistors are described. The influen ce of the base biasing resistance, emitter geometry and temperature on the noise spectra are discussed. The npn transistors studied exhibited 1/f and shot noise, but the pnp transistors are characterized by significant genera tion-recombination noise contributions to the total noise. For both types o f transistors, the measured output noise is determined primarily by the noi se sources in the polysilicon-monosilicon interface. The level of the 1/f n oise is proportional to the square of the base current for both npn and pnp transistors. The contribution of the 1/f noise in the collector current is also estimated. The area dependence of 1/f noise in both types of transist ors as well as other npn bipolar transistors are presented. (C) 2000 Elsevi er Science Ltd. All rights reserved.