ON NOISE SOURCES IN HOT ELECTRON-DEGRADED BIPOLAR JUNCTION TRANSISTORS

The effects of electrical stress on static characteristics and power s pectral density, S-lb, Of base current, I-b, fluctuations at low frequ encies, f<1 kHz, have been studied in quasiself-aligned bipolar n-p-n junction. In as-fabricated devices S(lb)proportional to 1/A(E) where A (E) is the transistor emitter area, whereas in strongly degraded trans istors S(ib)proportional to 1/P-E, where P-E is the transistor perimet er. The latter demonstrates directly that hot carrier-induced noise so urces are generated at the periphery of the transistors, In agreement with former work on hot electron-induced aging of bipolar junction tra nsistors. (C) 1997 American Institute of Physics.