LPCVD SILICON NITRIDE-ON-SILICON SPACER TECHNOLOGY

摘要

LPCVD silicon nitride is investigated for use as spacer material in bipolar emitter-base structures where the nitride is deposited directly on the silicon and thus becomes the e-b junction passivation material. This has a significant advantage for dimensional control due to nitride's high tolerance to HF etching, but several other material properties of the nitride, as compared to silicon dioxides, are points of concern and are addressed in this work: higher thin-film stress, lower diffusivity of hydrogen, higher electrical conductivity and more fixed charge storage. The processing parameters and device design are varied and correlated to the device characteristics. Conditions have been found that allow the fabrication of transistors with high yield and good I-V characteristics.