Effects of Self-Ion Bombardment on Al/Si(n) Schottky Barrier Formation

Abstract

ABSTRACTWe have employed a nozzle jet expansion technique to deposit Al thin film on chemically cleaned Si(n) surface. Pure Al is evaporated in a graphite crucible at a temperature of 15 50°C and is then ejected through a small nozzle into a vacuum region of 10-6 Torr. The Schottky barrier height of the as-deposited films is measured (using the J-V technique) to be 0.77eV, which is substantially higher than that obtained by conventional evaporation-deposition techniques(≤0.68eV). Our result suggests that an intimate Al/Si(n) contact has been formed during the jet expansion deposition of Al films.During the deposition, the Al jet beam can be partially ionized by electron bombardment. It is shown that the Schottky barrier height remain unchanged if a bias potential of V s0.5KeV is applied to the substrate during deposition. For Va >0.5 KeV, the diode became leaky and the barrier height was reduced. The energetic of the jet beam, with and without post ionization and acceleration, is discussed with respect to thin film and interface formation.