Method of making isolation grooves by over-filling with polycrystalline silicon having a difference in impurity concentration inside the grooves followed by etching off the overfill based upon this difference

Claim 1

A method of manufacturing a semiconductor circuit comprising the steps in the order mentioned below of: (a) forming a groove on one main surface of a semiconductor substrate such that an island region is defined by said groove; (b) oxidizing said main surface of said substrate including at least the surface of said groove to form an oxide film; (c) depositing a first semiconductor layer on said oxide film formed in step (b); (d) implanting an impurity by ion implantation such that said first semiconductor layer within said groove alone is doped with said impurity, thereby creating a difference between the impurity concentration of said first semiconductor layer within said groove and the impurity concentration of said first semiconductor layer above and adjacent said groove, said implanting being accomplished by use of an ion implantation voltage such that said impurity remains in said first semiconductor layer within said groove alone and passes through said first semiconductor layer above and adjacent said groove; (e) heating said first semiconductor layer; (f) selectively removing the first semiconductor layer above and adjacent said groove by utilizing said difference in impurity concentration; (g) depositing a second semiconductor layer over said first semiconductor layer in said groove and on the substrate surface adjacent said groove, said second semiconductor layer being deposited to a depth greater than the depth of said groove so that at the location of said groove said second semiconductor layer fills said groove and extends above the main surface of said substrate; (h) introducing said impurity from said first semiconductor layer into said second semiconductor layer whereby the impurity concentration of said second semiconductor layer within the groove is substantially different from the impurity concentration of said second semiconductor layer above and adjacent said groove; and (i) selectively removing said second semiconductor layer above and adjacent said groove by utilizing the difference in impurity concentration so as to allow the second semiconductor layer to remain only within the groove and, thus, to provide a region for separating two adjacent island regions.

Claim 2

A method of manufacturing a semiconductor circuit comprising the steps in the order mentioned below of: (a) forming a groove on one main surface of a semiconductor substrate such that an island region is defined by said groove; (b) oxidizing said main surface of said substrate including at least the surface of said groove to form an oxide film; (c) depositing a first semiconductor layer on said oxide film formed in step (b); (d) implanting an impurity by ion implantation such that said first semiconductor layer within said groove alone is doped with said impurity, thereby creating a difference between the impurity concentration of said first semiconductor layer within said groove and the impurity concentration of said first semiconductor layer above and adjacent said groove, said implanting being accomplished by use of an ion implantation voltage such that said impurity remains in said first semiconductor layer within said groove alone and passes through said first semiconductor layer above and adjacent said groove; (e) heating said first semiconductor layer; (f) selectively removing the first semiconductor layer above and adjacent said groove by utilizing said difference in impurity concentration; (g) depositing a second semiconductor layer over said first semiconductor layer in said groove and on the substrate surface adjacent said groove, said second semiconductor layer being deposited to a depth greater than the depth of said groove so that at the location of said groove said second semiconductor layer fills said groove and extends above the main surface of said substrate; (h) introducing said impurity from said first semiconductor layer into said second semiconductor layer whereby the impurity concentration of said second semiconductor layer within the groove is substantially different from the impurity concentration of said second semiconductor layer above and adjacent said groove; and (i) selectively removing said second semiconductor layer above and adjacent said groove by utilizing the difference in impurity concentration so as to allow the second semiconductor layer to remain only within the groove and, thus, to provide a region for separating two adjacent island regions.

Claim 3

A method of manufacturing a semiconductor circuit comprising the steps in the order mentioned below of: (a) forming a plurality of deposition layers on the surface of a semiconductor substrate with said deposition layers including an uppermost layer doped with a high concentration of an impurity; (b) forming a groove on one main surface of said semiconductor substrate such that an island region is defined by said groove and such that said deposition layers are removed in the area of said groove; (c) oxidizing the surface of said groove to form an oxide film in said groove; (d) depositing a semiconductor layer over said oxide film in said groove and over said deposition layers on the substrate surface adjacent said groove, said semiconductor layer being deposited to a depth greater than the depth of said groove so that at the location of said groove said semiconductor layer fills said groove above the main surface of said substrate; (e) introducing said impurity from said uppermost layer into said semiconductor layer whereby the impurity concentration of said semiconductor layer within said groove is substantially different from the impurity concentration of said semiconductor layer above and adjacent said groove; and (f) selectively removing the semiconductor layer above and adjacent said groove by utilizing the difference in impurity concentration so as to allow the semiconductor layer to remain only within said groove and, thus, to provide a region for separating two adjacent island regions.

Claim 4

A method of manufacturing a semiconductor circuit comprising the steps in the order mentioned below of: (a) forming a plurality of deposition layers on the surface of a semiconductor substrate with said deposition layers including an uppermost layer doped with a high concentration of an impurity; (b) forming a groove on one main surface of said semiconductor substrate such that an island region is defined by said groove and such that said deposition layers are removed in the area of said groove; (c) oxidizing the surface of said groove to form an oxide film in said groove; (d) depositing a semiconductor layer over said oxide film in said groove and over said deposition layers on the substrate surface adjacent said groove, said semiconductor layer being deposited to a depth greater than the depth of said groove so that at the location of said groove said semiconductor layer fills said groove above the main surface of said substrate; (e) introducing said impurity from said uppermost layer into said semiconductor layer whereby the impurity concentration of said semiconductor layer within said groove is substantially different from the impurity concentration of said semiconductor layer above and adjacent said groove; and (f) selectively removing the semiconductor layer above and adjacent said groove by utilizing the difference in impurity concentration so as to allow the semiconductor layer to remain only within said groove and, thus, to provide a region for separating two adjacent island regions.