Method of making insulated gate field effect transistor

Claim 1

The method of claim 10 wherein the metal film is an aluminum film.

Claim 4

A method of forming an aligned gate electrode of a metal-oxide-semiconductor field effect transistor, in a first conductivity semiconductor substrate comprising: a. diffusing selected second conductivity producing dopant atoms through an electrically insulative diffusion mask into selected areas of said first conductivity semi-conductor substrate to form second conductivity source and drain regions in selected areas of said first conductivity semiconductor substrate, with a portion of said electrically insulative diffusion mask which is between said source and drain electrodes being an aligned electrically insulative gate insulator layer; b. forming a metal film upon the masked first conductivity semiconductor substrate, said metal film thus being in contact with said second conductivity source and drain regions and said aligned electrically insulative gate insulator layer; c. masking selected areas of said metal film with an anodization mask, at least two of which selected areas are over the central portions of said second conductivity source and drain regions, and at least one of which selected area of said metal film is above said aligned electrically insulative gate insulator layer; and d. anodizing the selectively masked metal film in situ to delineate a metal source electrode connected to said second conductivity source region, a metal drain electrode connected to said second conductivity drain region and an aligned metal gate electrode above the aligned electrically insulative gate insulator layer.

Claim 5

A method of making an improved metal-oxide-semiconductor field effect transistor having an aligned gate electrode in a first conductivity semiconductor substrate, comprising: a. forming a first aluminum film on said first conductivity semiconductor substrate; b. masking with an anodization mask selected areas of said first aluminum film including at least two selected areas, in which second conductivity source and drain regions of metal-oxide semiconductor field effect transistors are to be formed in said first conductivity semiconductor substrate; c. anodizing the selectively masked first aluminum film, which first aluminum film is on said first conductivity semiconductor substrate, into electrically insulative aluminum oxide; d. removing said mask from the unanodized portions of the first aluminum film; e. etching away the unanodized aluminum areas from said first conductivity semiconductor substrate to leave an aluminum oxide diffusion mask on said first conductivity semiconductor substrate; f. diffusing selected second conductivity producing dopant atoms through the aluminum oxide diffusion mask into said first conductivity semiconductor substrate, to form second conductivity source and drain regions in said first conductivity semiconductor substrate and to delineate an aligned aluminum oxide gate insulator layer between said source and drain regions; g. forming a second aluminum film upon said second conductivity semiconductor substrate, said second aluminum film also being in contact with said aluminum oxide diffusion mask, with said second conductivity source and drain regions, and in contact with said aluminum oxide gate insulator layer; h. masking selected areas of said second aluminum film, with an anodization mask including at least selected areas over central portions of said second conductivity source and drain regions, and also above said aluminum oxide gate insulator layer between said second conductivity source and drain regions; and i. anodizing the selectively masked second aluminum film to delineate an aluminum source electrode connected to said second conductivity source region, an aluminum drain electrode connected to said second conductivity drain region and an aligned aluminum gate electrode upon Said aligned aluminum oxide gate insulator layer, said aligned aluminum gate electrode being precisely aligned between the second conductivity source and drain regions, to thus form an improved metal-oxide-semiconductor field effect transistor.