1/f noise characterization of base current and emitter interfacial oxide breakup in n-p-n polyemitter bipolar transistors

We propose using base 1/f noise to characterize the distribution of diffusion and tunneling components of base-current (I/sub b/) at the emitter poly/monosilicon interface in n-p-n polyemitter transistors. A noise model is constructed to interpret the I/sub b/ 1/f noise (S/sub iEB/) dependence on these combined currents. Measured I/sub b/ dependences of S/sub iEB/ increase progressively from I/sub b//sup 1.2/ to I/sub b//sup 2.0/ for transistors having emitter structures concomitant with increasing current gains and series emitter resistances ranging between 115-1800 and 7-33/spl Omega/, respectively. This is indicative of tunneling components in I/sub b//sup 2.0/ that increase with higher interfacial oxide continuity, and persist in epitaxially realigned emitters. >