Characterization of arsenic doping profile across the polycrystalline Si/Si interface in polycrystalline Si emitter bipolar transistors

Abstract

The combination of Z-contrast scanning transmission electron microscopy, transmission electron microscopy, and secondary ion mass spectroscopy allows the most accurate determination, to date, of the As doping profile across the polycrystalline Si/Si interface of an npn polycrystalline Si emitter bipolar transistor. We measure a peak in the As doping profile which is coincident with the polycrystalline Si/Si crystallographic interface and is approximately 40 Å full width at half-maximum. There is a uniform As dopant level in the polycrystalline Si emitter of 2×1020 cm−3 and an estimated maximum As concentration of 5×1020 cm−3 in the peak at the interface.