Low Temperature In-Situ Processing for Si-MBE

Abstract
A basic process sequence for low temperature in-situ processing of metal-insulator-semiconductor (MIS) structures in an ultra-high vacuum (UHV) multichamber system is presented. It includes conditioning of the process chamber by plasma heating, in-situ cleaning of silicon wafers, and conventional silicon molecular beam epitaxy (Si-MBE). The in-situ cleaning is achieved by an argon/hydrogen plasma treatment of the wafer surface at temperatures well below 400° C. The native oxide as well as carbon compounds are removed from the silicon surface. Etch rates for SiO2 are determined for various plasma parameters. Without additional cleaning procedures, silicon films are deposited in another process step using a quadrupole mass spectrometer controlled electron beam evaporator. Epitaxial films are obtained for substrate temperatures as low as 500°C on (100) and 600°C on (111) silicon for deposition rates of 0.05 nm/s.