A combined UHV-CVDand rapid thermal diffusion process for SiGe Esaki diodes by ultra shallow junction formation

Abstract

In this paper we show that SiGe Esaki diodes can be fabricated by ultra-high vacuum chemical vapor deposition (UHV-CVD), which opens a new possibility for the integration of the diodes into VLSI-circuits. Generally, UHV-CVD produces sharp heterostructure interfaces, high B-doping levels and abrupt doping profiles, which are crucial for the Esaki diodes. The ultra shallow junction is formed via proximity diffusion of P in a rapid thermal process using a spin-on dopant source. We compare data for diodes diffused under various conditions, including diodes where we etched off the top Si cap layer with a selective etch. The calculated band structures are shown.