Tapering of oxidized polysilicon electrodes

Claim 2

A thickly oxidized polysilicon electrode structure comprised of a doped polysilicon electrode structure and a layer of silicon dioxide grown from and overlying said polysilicon electrode structure, wherein (1) the thickness t o of the silicon dioxide layer is about 0.7 microns and the thickness of the underlying polysilicon is about 0.6 microns such that t o ≦1.5 t ps , where t ps is the thickness of the underlying polysilicon, and (2) the profile of the thickly oxidized polysilicon electrode structure at an edge thereof is tapered so as not to have an inward curvature.

Claim 3

A structure as claimed in claim 1 further comprising an electrode structure overlying said thickly oxidized polysilicon electrode structure, said overlying electrode structure, in the region of a step, (1) being free from cracks and voids therebeneath, and (2) having a thickness which does not fall below about 25 percent of its nominal thickness in the region proximate the step region.

Claim 4

A structure as claimed in claim 2 wherein said overlying electrode structure is comprised of a metal that has been deposited by an evaporation process.

Claim 5

A structure as claimed in claim 3 wherein said overlying electrode structure is comprised of aluminum.

Claim 6

In apparatus for use in a photosensitive device comprising: (a) a substrate structure comprised of a semiconductor material of one conductivity type having an overlying layer of insulating material; (b) an enable gate structure comprised of a strip of electrically conductive material extending across a length of said substrate structure; (c) an isolating gate structure comprised of a strip of electrically conductive material extending across a length of said substrate structure, said isolating gate structure being disposed substantially parallel to said enable gate structure; (d) a plurality of overlying address gate structures each of which is comprised of a strip of electrically conductive material that extends over, but is electrically insulated from, said enable gate structure and said isolating gate structure, said enable gate structure and/or said address gate structure being transmissive to incident radiation so as to form a row of photosites; and (e) a read channel formed in said substrate structure comprised of a semiconductor material having a conductivity type opposite that of said substrate semiconductor material, said read channel being proximately disposed to said isolating gate structure, the improvement wherein at least one of said enable and isolating gate structures is comprised of a thickly oxidized polysilicon electrode structure, said thickly oxidized polysilicon electrode structure being comprised of a doped polysilicon electrode structure and a layer of silicon dioxide grown from and overlying said polysilicon electrode structure, wherein (1) the thickness t o of the silicon dioxide layer is about 0.7 microns and the thickness of the underlying polysilicon is about 0.6 microns such that t o ≦1.5 t ps , where t ps is the thickness of the underlying polysilicon, and (2) the profile of the thickly oxidized polysilicon electrode structure at an edge thereof is tapered so as not to have an inward curvature.

Claim 7

In apparatus for use in a photosensitive device comprising: (a) a substrate structure comprised of a semiconductor material of one conductivity type having an overlying layer of insulating material; (b) an enable gate structure comprised of a strip of electrically conductive material extending across a length of said substrate structure; (c) an isolating gate structure comprised of a strip of electrically conductive material extending across a length of said substrate structure, said isolating gate structure being disposed substantially parallel to said enable gate structure; (d) a plurality of overlying address gate structures each of which is comprised of a strip of electrically conductive material that extends over, but is electrically insulated from, said enable gate structure and said isolating gate structure, said enable gate structure and/or said address gate structure being transmissive to incident radiation so as to form a row of photosites; and (e) a read channel formed in said substrate structure comprised of a semiconductor material having a conductivity type opposite that of said substrate semiconductor material, said read channel being proximately disposed to said isolating gate structure, the improvement wherein at least one of said enable and isolating gate structures is comprised of a thickly oxidized polysilicon electrode structure, said thickly oxidized polysilicon electrode structure being comprised of a doped polysilicon electrode structure and a layer of silicon dioxide grown from and overlying said polysilicon electrode structure, wherein (1) the thickness t o of the silicon dioxide layer is about 0.7 microns and the thickness of the underlying polysilicon is about 0.6 microns such that t o ≦1.5 t ps , where t ps is the thickness of the underlying polysilicon, and (2) the profile of the thickly oxidized polysilicon electrode structure at an edge thereof is tapered so as not to have an inward curvature.

Claim 8

Apparatus as claimed in claim 5 wherein said overlying address gate structure, in the region of a step of said oxidized polysilicon electrode structure, (1) is free from cracks and voids therebeneath, and (2) has a thickness which does not fall below about 25 percent of its nominal thickness in the region proximate the step region.

Claim 9

A structure as claimed in claim 5 wherein said overlying address gate structure is comprised of a metal that has been deposited by an evaporation process.

Claim 10

A structure as claimed in claim 7 wherein said overlying address gate structure is comprised of aluminum.