Method of manufacture of a uniphase CCD

Claim 2

In the manufacture of a uniphase charge coupled device, the process of providing a desired doping concentration in a semiconductive substrate for use in the charge-coupled device comprising the steps of: forming over the substrate a mask including a plurality of strip portions, each including a central portion of one material with vertical side walls and edge portions of a different material on opposite side walls of the central portion; implanting ions of one type through the mask into exposed regions of the substrate; removing corresponding ones of the edge portions of each strip; implanting ions of both the one and the opposite types into the exposed region of the substrate; removing the central portion of each strip; implanting ions of the one type into exposed regions of the substrate; and removing the remaining edge portion of each strip.

Claim 3

The process of claim 1 in which the mask strips include a central portion of polysilicon and edge portions of silicon oxide and the substrate includes an etch-stop layer of silicon nitride between the surface of the substrate and the strips of the mask.

Claim 4

The process of claim 1 in which the substrate is n-type and includes a surface layer of implanted boron and the implanted ions of the opposite type are of arsenic.

Claim 5

The process of providing a substrate for use in a buried channel uniphase charge-coupled device comprising the steps of: preparing an n-type silicon substrate; implanting boron ions into the upper surface of the substrate for forming a boron-rich upper surface layer; forming in turn a silicon oxide layer and a silicon nitride layer over the upper surface layer of the substrate; forming a mask over the silicon nitride layer including a plurality of spaced strips, each including a polysilicon central portion having an opposed pair of vertical side walls and a separate silicon oxide edge portions on each of the two side walls of each central portion; implanting through the mask exposed regions of the substrate with boron ions; removing selectively the silicon oxide edge portions from the corresponding ones of the side walls of the strips of the mask; implanting through the mask boron and arsenic ions into exposed regions of the substrate; removing selectively the central portions of each strip and leaving only the remaining edge portion of each strip of the mask; and implanting through the mask boron ions into the exposed regions of the substrate.

Claim 6

The process of providing a substrate for use in a buried channel uniphase charge-coupled device comprising the steps of: preparing an n-type silicon substrate; implanting boron ions into the upper surface of the substrate for forming a boron-rich upper surface layer; forming in turn a silicon oxide layer and a silicon nitride layer over the upper surface layer of the substrate; forming a mask over the silicon nitride layer including a plurality of spaced strips, each including a polysilicon central portion having an opposed pair of vertical side walls and a separate silicon oxide edge portions on each of the two side walls of each central portion; implanting through the mask exposed regions of the substrate with boron ions; removing selectively the silicon oxide edge portions from the corresponding ones of the side walls of the strips of the mask; implanting through the mask boron and arsenic ions into exposed regions of the substrate; removing selectively the central portions of each strip and leaving only the remaining edge portion of each strip of the mask; and implanting through the mask boron ions into the exposed regions of the substrate.