Method of making an mos transistor including a gate insulator layer of aluminum oxide and the article so produced

Claim 2

A method according to claim 1 in which said thick aluminum layer has a thickness of about 5000 Angstroms and said thin aluminum layer has a thickness of about 250-800 Angstroms.

Claim 3

In a method of fabricating an MOS transistor of the type including a silicon semiconductor body of one conductivity type, spaced, source and drain regions of different conductivity type extending to a major surface of said body and a gate electrode composed of a layer of oxide on said surface of said body between said source and drain regions and a layer of metal on said oxide, the steps of: forming a relatively thick layer of silicon dioxide on said surface, removing tHe silicon dioxide of said layer which is over the area of said gate electrode and said source and drain regions, depositing a relatively thick layer of a contact metal over said entire wafer surface, defining metal connections for said source and drain regions from said layer of contact metal and removing said contact metal from the remaining portions of said wafer surface, depositing a relatively thin layer of aluminum over said entire wafer surface including an exposed silicon surface at the gate region, converting said thin aluminum metal layer to aluminum oxide by anodization, depositing a relatively thick layer of metal on said aluminum oxide over said gate region, and defining said last mentioned metal layer to form a gate electrode.