Method for manufacturing semiconductor devices having oxide films and

Abstract

A silicon crystal body having a major surface lying parallel to a {110} or {100} crystal plane is prepared. A silicon oxide film is formed on the major surface by heating the body in an atmosphere containing steam. Then, an aluminum layer is formed on the oxide film. Thereby the amount of surface donors induced in the major surface of the body by the existence of the oxide film is smaller than the amount of induced surface donors to be obtained in a crystal plane of a like silicon body but lying parallel to a {111} plane covered with a like oxide film. The amount of induced surface donors is further reduced by subjecting said body to a heat treatment under application across said oxide film of such a voltage as that which renders the aluminum layer provided on the oxide film negative polarity. This invention is applied to the manufacture of, for example, MOS field effect transistors, MOS diodes and so-called planar transistors.