Modeling the variation of the low-frequency noise in polysilicon emitter bipolar junction transistors

The variation of the low-frequency noise in polysilicon emitter bipolar jun ction transistors (BJTs) was investigated as a function of emitter area (A( E)) For individual BJTs with submicron-sized As, the low-frequency noise st rongly deviated from a 1/f-dependence. The averaged noise varied as 1/f, wi th a magnitude proportional to A(E)(-1), while the variation in the noise l evel was found to vary as A(E)(-1.5). A new expression that takes into acco unt this deviation is proposed for SPICE modeling of the the low-frequency noise, The traps responsible for the noise were located to the thin SiO2 in terface between the polysilicon and monosilicon emitter, The trap's energy level, areal concentration and capture cross-section were estimated to 0.31 eV, 6 x 10(8) cm(-2) and 2 x 10(-19) cm(2), respectively.