Planar substrate with patterned silicon-on- insulator region and self-aligned trench
OwnerAtul Ajmera, Devendra K. Sadana +1inventors
InventorsAtul Ajmera, Devendra K. Sadana, Dominic J. Schepis
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Abstract
A process for forming a planar silicon-on-insulator (SOI) substrate comprising a patterned SOI region and a bulk region, wherein the substrate is free of transitional defects. The process comprises removing the transitional defects by creating a self-aligned trench adjacent the SOI region between the SOI region and the bulk region.
Claims21
A process for forming a planar silicon-on-insulator (SOI) substrate comprising a patterned SOI region having an oxide layer and a bulk region, wherein the substrate is free of transitional defects, the process comprising removing the transitional defects by creating a self-aligned trench adjacent the SOI region between the SOI region and the bulk region.
A process for forming buried silicon oxide regions in a silicon substrate having a silicon oxide surface layer and a surface protective layer comprising silicon nitride or polysilicon, over said silicon oxide surface layer, the process comprising the steps of:
- (a) forming over said surface protective layer a mask, having a top surface and side walls, to mask a portion of the substrate other than the regions of the buried silicon oxide;
- (b) depositing a side wall cover layer selected from the group consisting essentially of silicon nitride and silicon oxide-silicon nitride composite on the mask side walls said side wall cover layer also extending over a portion of the surface protective layer;
- (c) removing the surface protective layer not under the mask and the side wall cover layer to expose portions of the silicon oxide surface layer;
- (d) implanting oxygen ions in the silicon substrate areas under the exposed portions of the silicon oxide surface layer to form a buried oxide layer having a top surface and a bottom surface;
- (e) annealing the exposed portion of the silicon oxide surface layer to form a thick surface silicon oxide area and annealing the buried oxide layer;
- (f) removing the side wall cover layer and the surface protective layer under the side wall cover layer to expose a portion of the substrate;
- (g) forming a trench in the exposed portion of the substrate extending between the mask side walls and the thick surface silicon oxide layer and extending in said substrate to at least the top surface of the buried oxide layer;
- (h) removing the mask;
- and
- (i) filling the trench with a fill material.
A planar silicon-on-insulator (SOI) substrate comprising a patterned SOI region and a bulk region free of transitional defects, wherein the transitional defects are removed by creating a self-aligned trench adjacent the SOI region between the SOI region and the bulk region.
Dependencies are inferred from the claim text.