Technique for producing small islands of silicon on insulator
First Claim
1. A method for manufacturing a silicon on insulator substrate, comprising the steps of:
- directionally etching a silicon substrate, to form a plurality of trenches between protruding silicon rows;
forming a silicon nitride cap on the silicon rows, extending partway down the sides of the trenches;
isotropically etching the trenches, to partially undercut the silicon rows; and
oxidizing the substrate, to fully undercut the silicon rows.
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Abstract
Using sub-micron technology, silicon on insulator (SOI) rows and islands are formed in a silicon substrate. Trenches are directionally-etched in the silicon substrate, leaving rows of silicon between the trenches. Silicon nitride is then deposited over the trenches, extending partly down the sides of the trenches. An isotropic chemical etch is then used to partially undercut narrow rows of silicon in the substrate. A subsequent oxidation step fully undercuts the rows of silicon, isolating the silicon rows from adjacent active areas. Devices, such as transistors for CMOS and DRAMs, are then formed in active areas, wherein the active areas are defined on the silicon rows by LOCal Oxidation of Silicon (LOCOS).
243 Citations
10 Claims
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1. A method for manufacturing a silicon on insulator substrate, comprising the steps of:
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directionally etching a silicon substrate, to form a plurality of trenches between protruding silicon rows; forming a silicon nitride cap on the silicon rows, extending partway down the sides of the trenches; isotropically etching the trenches, to partially undercut the silicon rows; and oxidizing the substrate, to fully undercut the silicon rows. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification