Technique for producing small islands of silicon on insulator
AssigneeMicron Technology, Inc.
InventorLeonard Forbes
Life of this patent
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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).
Claims26
A method for manufacturing a silicon on insulator substrate, comprising:
- etching parallel trench regions in a substrate to form a plurality of trenches between a plurality of protruding silicon structures;
- depositing a layer of an etch-resistant material on the silicon structures, the material extending partway down the sides and covering the bottom of the trenches,
- patterning the protruding silicon structures with a mask and etching the unmasked areas to remove the etch resistant material from the bottom of the trenches;
- partially undercutting the plurality of protruding silicon structures;
- and
- forming oxide under the remaining portions of the plurality of protruding silicon structures.
A method for manufacturing a silicon on insulator substrate, comprising the steps of:
- etching a silicon substrate to form trenches between a plurality of silicon structures;
- depositing etch-resistant material on the silicon structures extending partway down and across the bottom of the trenches;
- removing the etch resistant material from the bottom of the trenches;
- etching the trenches so as to partially undercut the silicon structures;
- and
- oxidizing the substrate to the extent required to form an insulating layer fully under the silicon structures.
A method for manufacturing a silicon on insulator substrate, comprising:
- forming a plurality of trenches between a plurality of silicon rows to expose protruding silicon structures
- forming an etch-resistant cap on the silicon structures, the etch resistant cap extending partway down the sides and etch resistant material of the cap also extending across the bottom of the trenches;
- removing the etch resistant material from the bottom of the trenches;
- partially undercutting the plurality of protruding silicon structures;
- forming oxide under remaining portions of the plurality of protruding silicon structures;
- and
- separating the plurality of protruding silicon structures into a plurality of active areas.
Dependencies are inferred from the claim text.