CHARACTERIZATION OF ARSENIC DOPING PROFILE ACROSS THE POLYCRYSTALLINESI SI INTERFACE IN POLYCRYSTALLINE SI EMITTER BIPOLAR-TRANSISTORS/

The combination of Z-contrast scanning transmission electron microscop y, transmission electron microscopy, and secondary ion mass spectrosco py allows the most accurate determination, to date, of the As doping p rofile across the polycrystalline Si/Si interface of an npn polycrysta lline Si emitter bipolar transistor. We measure a peak in the As dopin g profile which is coincident with the polycrystalline Si/Si crystallo graphic interface and is approximately 40 angstrom full width at half- maximum. There is a uniform As dopant level in the polycrystalline Si emitter of 2 X 10(20) cm-3 and an estimated maximum As concentration o f 5 X 10(20) cm-3 in the peak at the interface.