Method of producing a thin silicon-on-insulator layer
First Claim
1. A method of forming a thin semiconductor layer of substantially uniform thickness upon which semiconductor structures can be subsequently formed, comprising the steps of:
- forming layer of silicon upon a silicon substrate;
implanting ions into said silicon layer in order to form a buried layer therein, said buried layer having etch characteristics which differ from those of said silicon layer;
bonding said silicon layer to a mechanical substrate;
removing said silicon substrate and portions of said silicon layer between said silicon substrate and said buried layer; and
removing said buried layer without removing under-laying portions of said silicon layer,whereby said underlaying portions of said silicon layer remain on said mechanical substrate to form the thin semiconductor layer.
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Accused Products
Abstract
A method of forming a thin silicon layer upon which semiconductor devices may be constructed. An epitaxial layer is grown on a silicon substrate, and oxygen or nitrogen ions are implanted into the epitaxial layer in order to form a buried etch-stop layer therein. An oxide layer is grown on the epitaxial layer, and is used to form a bond to a mechanical support wafer. The silicon substrate is removed using grinding and/or HNA, the upper portions of the epitaxy are removed using EDP, EPP or KOH, and the etch-stop is removed using a non-selective etch. The remaining portions of the epitaxy forms the thin silicon layer. Due to the uniformity of the implanted ions, the thin silicon layer has a very uniform thickness.
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Citations
27 Claims
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1. A method of forming a thin semiconductor layer of substantially uniform thickness upon which semiconductor structures can be subsequently formed, comprising the steps of:
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forming layer of silicon upon a silicon substrate; implanting ions into said silicon layer in order to form a buried layer therein, said buried layer having etch characteristics which differ from those of said silicon layer; bonding said silicon layer to a mechanical substrate; removing said silicon substrate and portions of said silicon layer between said silicon substrate and said buried layer; and removing said buried layer without removing under-laying portions of said silicon layer, whereby said underlaying portions of said silicon layer remain on said mechanical substrate to form the thin semiconductor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of forming a thin semiconductor layer of substantially uniform thickness upon which semiconductor structures may be subsequently formed, comprising the steps of:
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growing an silicon layer of a second conductivity type upon a silicon substrate of a first conductivity type; implanting ions into said epitaxial layer in order to form a substantially planar buried layer of substantially uniform thickness therein, said buried layer having etch characteristics which appreciably differ from those of said epitaxial layer; bonding said epitaxial layer to a mechanical substrate; removing said semiconductor substrate and a portion of said epitaxial layer in an etchant which attacks silicon of said first conductivity type while not appreciably attacking silicon of said second conductivity type; etching remaining portions of said epitaxial layer overlaying said buried layer in an etchant which does not appreciably attack underlaying portions of said buried layer; and etching said buried layer in an etchant which does not appreciably attack underlaying portions of said epitaxial layer, said underlaying portions of said epitaxial layer remaining on said mechanical substrate to form the thin semiconductor layer. - View Dependent Claims (22, 23, 24)
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25. A method for forming a thin silicon-on-insulator structure, comprising:
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forming a silicon layer of a first conductivity type on a first semiconductor wafer of a second conductivity type establishing a N/P junction therewith within said silicon layer; implanting into a portion of said silicon layer ions of a material which has different etching characteristics than the adjoining first portions of said silicon layer, to form a buried layer; forming a silicon dioxide layer on said silicon layer, and bonding onto said silicon dioxide layer a second semiconductor wafer; removing said first semiconductor wafer and a portion of said silicon layer disposed between said first semiconductor layer and said buried layer with a first etchant which attacks silicon of said first conductivity type without attacking silicon of said second conductivity type, so as to expose said N/P junction; removing a remainder of said portion of said silicon layer disposed between said first semiconductor layer and said buried layer with a second etchant that stops appreciable etching at said buried layer; and removing said buried layer with a third etchant which stop etching at the underlaying unimplanted portion of said silicon layer, thereby resulting in a thin sliicon layer of a predetermined uniform thickness atop a silicon diioxide layer which is atop said second semiconductor wafer.
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26. A method of forming a silicon-on-insulator structure, comprising the steps of:
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growing an epitaxial layer of a second conductivity type on a silicon substrate of a first conductivity type in order to form a N/P junction therewith within said epitaxial layer; forming a silicon dioxide layer on an exposed surface of said epitaxial layer; implanting dopant ions through said silicon dioxide layer into said epitaxial layer in order to form a buried layer of said first conductivity type within said epitaxial layer; bonding said silicon substrate to a mechanical substrate, using said silicon dioxide layer as a bonding material; removing said silicon substrate and portions of said epitaxial layer between said silicon substrate and said N/P junction with a first etchant which does not appreciably attack silicon of said second conductivity type; removing portions of said epitaxial layer between said N/P junction and a peak concentration of said dopant ions within said buried layer with a second etchant; and removing remaining portions of said buried layer with said of first etchant, remaining portions of said epitaxial layer overlaying said silicon dioxide layer to form the silicon-on-insulator structure. - View Dependent Claims (27)
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Specification