2.4 Formation of various metal semiconductor junctions by means of ion evaporation

Abstract

Abstract The paper deals with the result of some preliminary experiments of applying ion-evaporated metal layers to silicon and heat treatment of the samples. Ion evaporation is based on the electron beam evaporation, namely, the ions arising from the 180° deflection type e-gun are accelerated to cause implantation effects during the condensation of the neutral particles. The accelerating voltage is typically 20 kV, the ion current 5–20 mA. Four metals have been chosen for the experiments: Al, Ni, Cu and Mo. The I–V-characteristics of the contacts deposited by ion evaporation were ohmlc. The curves appreciably changed after heat treatment of the samples at 400, 500 and 580°C. The AlSi contacts had very high resistivity after the treatment at 400°C, but then Al alloyed diode type contacts were achieved at 500°C. Ni and Mo formed alloyed type contacts at 580°C, and similar results were obtained in case of Cu. Very interesting results were obtained for Ni and Mo at 500°C, where we obtained I–V-characteristics of the Schottky-diode type, but with the reverse polarity.