Method of fabricating semiconductor devices

Claim 3

The method recited in claim 1 wherein said disposing step comprises disposing a layer of aluminum dopant material over said other remaining portions of said first masking layer and said exposed surface portions.

Claim 4

The method recited in claim 1 wherein said first masking layer consists substantially of silicon oxide.

Claim 5

A method as claimed in claim 3 wherein: said second etching step is carried out for a time which is long enough that said islands are removed but short enough to leave some of said first masking material on said surface.

Claim 6

A method as claimed in claim 3 wherein: said disposing step is performed in a manner causing substantially no diffusion of the dopant into said body during said disposing step.

Claim 7

A method as claimed in claim 3 further comprising: megasonically agitating said etchant during said second etching step.

Claim 8

A method as claimed in claim 3 wherein: said second etching step is carried out for a time long enough to remove said other remaining portions of said first masking layer.

Claim 9

A method as claimed in claim 3 wherein said body is silicon and said first forming step comprises: thermally growing a masking layer of silicon dioxide on said surface of said body.

Claim 10

The method recited in claim 8 wherein said thermally growing step produces a silicon dioxide layer about 10,000 angstroms thick.

Claim 11

Method of fabricating a silicon semiconductor device comprising the steps of: first forming a first masking layer of silicon oxide on a surface of a body of semiconductor material; removing preselected portions of said first masking layer to expose surface portions of said body, other portions of said first masking layer remaining on said surface; disposing a layer of aluminum dopant material over said other remaining portions of said first masking layer and said exposed surface portions, said aluminum having a diffusion coefficient with respect to said silicon oxide masking material which is large enough that allowing the aluminum to remain on said silicon oxide masking layer during diffusion of said aluminum into said semiconductor material would be detrimental to the intended device characteristics; second forming a second masking layer over said layer of aluminum dopant material and selectively retaining said second masking layer to protect those portions of said layer of aluminum dopant material which overlie said exposed surface portions, while leaving the rest of said layer of aluminum unprotected; first etching said unprotected portions of said layer of aluminum in an attempt to remove substantially all of said aluminum from said other remaining portions of said silicon oxide layer; and second etching said other remaining portions of said silicon oxide layer with an etchant which selectively attacks said silicon oxide masking material, said second etching being carried out for a time which is long enough to remove any islands of aluminum on said other remaining portions of said silicon oxide masking layer which may not have been removed in said first etching step; and heating said body to a diffusion temperature for said aluminum dopant material in said silicon semiconductor body for a time sufficient to produce a P type diffused region of a desired depth in which the conductivity type of said diffused region is controlled by said aluminum dopant material and said diffused region is at least partially bounded by a PN junction with a portion of said semiconductor body having an N type conductivity.

Claim 12

Method of fabricating a silicon semiconductor device comprising the steps of: first forming a first masking layer of silicon oxide on a surface of a body of semiconductor material; removing preselected portions of said first masking layer to expose surface portions of said body, other portions of said first masking layer remaining on said surface; disposing a layer of aluminum dopant material over said other remaining portions of said first masking layer and said exposed surface portions, said aluminum having a diffusion coefficient with respect to said silicon oxide masking material which is large enough that allowing the aluminum to remain on said silicon oxide masking layer during diffusion of said aluminum into said semiconductor material would be detrimental to the intended device characteristics; second forming a second masking layer over said layer of aluminum dopant material and selectively retaining said second masking layer to protect those portions of said layer of aluminum dopant material which overlie said exposed surface portions, while leaving the rest of said layer of aluminum unprotected; first etching said unprotected portions of said layer of aluminum in an attempt to remove substantially all of said aluminum from said other remaining portions of said silicon oxide layer; and second etching said other remaining portions of said silicon oxide layer with an etchant which selectively attacks said silicon oxide masking material, said second etching being carried out for a time which is long enough to remove any islands of aluminum on said other remaining portions of said silicon oxide masking layer which may not have been removed in said first etching step; and heating said body to a diffusion temperature for said aluminum dopant material in said silicon semiconductor body for a time sufficient to produce a P type diffused region of a desired depth in which the conductivity type of said diffused region is controlled by said aluminum dopant material and said diffused region is at least partially bounded by a PN junction with a portion of said semiconductor body having an N type conductivity.

Claim 15

The method recited in claim 11 wherein: said second etching step is carried out for a time which is such that said islands are removed, but for a time short enough to leave some of said first masking material on said surface.

Claim 16

The method recited in claim 12 wherein said first masking material is silicon oxide.

Claim 17

The method recited in claim 11 wherein said disposing step comprises disposing a layer of aluminum dopant material over said other remaining portions of said first masking layer and said exposed surface portions and said PN junction is with an N type portion of said body.