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US 4,885,257 AGranted
Gettering process with multi-step annealing and inert ion implantation
AssigneeKabushiki Kaisha Toshiba
InventorYoshiaki Matsushita
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Abstract
A semiconductor substrate and process for making are disclosed. The substrate is suitable for use in manufacturing large scale integrated circuits. The process comprises the steps of heating a semiconductor substrate at a temperature not lower than 1100.degree. C., implanting electrically inert impurities into the major surface of the substrate, heating the substrate at a temperature ranging from 600.degree. to 900.degree. C. and providing a single crystal semiconductor layer.
Claims3
A process for producing a semiconductor substrate comprising the steps of:
- heating a semiconductor substrate material with a first resistivity at a temperature not less than 1100.degree. C. in order to change a major surface of said substrate material into a high resistivity semiconductor layer with a second resistivity higher than said first resistivity, said high resistivity semiconductor layer having resistivity more than 1 ohm cm at a depth of 1.5 um from said major surface of said substrate material,
- implanting electrically inert impurities into said major surface of said substrate material to produce defect centers in said high resistivity semiconductor layer.
- heating said substrate material at a temperature ranging from 600.degree. to 900.degree. C. to generate micro defects in both of said substrate material and said high resistivity semiconductor layer, and
- providing a single crystal semiconductor layer with a third resistivity between said first and second resistivity on said major surface of said substrate material, said third resistivity being larger than said first resistivity.
1 more element
Dependencies are inferred from the claim text.