Abstract A semiconductor substrate which contains a buried grid-like region of enhanced concentration of an impurity type opposite to that of the semiconductor substrate; and method for the fabrication thereof which includes providing beneath the upper surface of a semiconductor substrate at a first depth a continuous region of a first impurity type which is the same as that of the semiconductor substrate and wherein at preselected isolated discontinuous locations beneath said surface the first impurity type is at a second depth beneath said surface which is greater than said first depth, and then providing beneath said first depth and substantially coincident with said second depth, a second impurity type opposite to that of the first type and at a dosage level lower than the dosage level of the first impurity type so as to provide a grid-like region of enhanced concentration of impurity type opposite to that of the semiconductor substrate for collecting excess minority carriers in the semiconductor substrate.
In a semiconductor substrate wherein the improvement comprises a buried interconnected grid-like region of enhanced concentration of impurity type opposite to that of the semiconductive substrate for collecting excess minority carriers generated in the semiconductor substrate.
Claim 2
Dependent Claim
36 words
In a semiconductor substrate wherein the improvement comprises a buried interconnected grid-like region of enhanced concentration of impurity type opposite to that of the semiconductive substrate for collecting excess minority carriers generated in the semiconductor substrate.
Claim 3
Dependent Claim
59 words
The semiconductor substrate of claim 1 wherein vias in the grid-like region are provided by impurities which are the same type as the impurities of the semiconductive substrate and opposite from the impurities of the grid-like structure, and wherein the dosage of the impurities providing the vias of the grid-like structure is higher than that of the grid-like structure.
Claim 4
Dependent Claim
38 words
The semiconductor substrate of claim 1 or 2 wherein a region of enhanced concentration of impurity type the same as that of the semiconductor substrate and opposite that of the grid-like region is located above the grid-like region.
Claim 5
Dependent Claim
23 words
The semiconductor substrate of claim 1 or 2 wherein said impurity type opposite to that of the semiconductor substrate is an n-type material.
Claim 6
Dependent Claim
29 words
The semiconductor substrate of claim 1 or 2 wherein the vias in the grid-like region are aligned to the least sensitive portions of the circuitry on the semiconductor substrate.
Claim 7
Dependent Claim
24 words
The semiconductor substrate of claim 1 wherein the grid-like region is about 1 to about 5 microns below the upper surface of the substrate.
Claim 8
Dependent Claim
24 words
The semiconductor substrate of claim 1 wherein the peak concentration of the grid-like structure is about 2.5 microns below the surface of the substrate.
Claim 9
Dependent Claim
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The semiconductor substrate of claim 1 wherein the grid-like region is about 0.5 microns thick.
Claim 10
Dependent Claim
17 words
The semiconductor substrate of claim 1 wherein said grid is not electrically connected to any power supply.