Method for making low barrier Schottky devices of the electron beam evaporation of reactive metals

Abstract

A method for making low barrier Schottky devices by the electron beam evaporation of a reactive metal such as tantalum, titanium, hafnium, tungsten, molybdenum, and niobium which is selectively deposited at a semiconductor surface such as n-type silicon using a photoresist mask. The method includes a series of steps during the deposition of the barrier metal for degassing the semiconductor substrate, photoresist mask, reactive metal charge and deposition chamber. More particularly, the method includes steps for preliminarily degassing the substrate, mask and surrounding chamber by infra red heating under vacuum followed by steps for preliminarily degassing the charge and surrounding chamber, while the substrate and mask are shielded by electron beam heating the charge while under vacuum. Thereafter, and prior to deposition, the substrate and mask are finally degassed by irradiation with X-rays produced by electron beam heating the charge to a temperature below evaporation for a predetermined time under vacuum. Upon further heating of the charge, the barrier metal is evaporated and deposited at the semiconductor substrate surface.

Dependencies are inferred from the claim text.