Silicon-germanium-carbon compositions in selective etch processes
AssigneeLawrence Semiconductor Research Laboratory, Inc.
InventorsMcDonald Robinson, Richard C. Westhoff, Charles E. Hunt, Li Ling
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Abstract
Silicon-germanium-based compositions comprising silicon, germanium, and carbon (i.e., Si--Ge--C), methods for growing Si--Ge--C epitaxial layer(s) on a substrate, etchants especially suitable for Si--Ge--C etch-stops, and novel methods of use for Si--Ge--C compositions are provided. In particular, the invention relates to Si--Ge--C compositions, especially for use as etch-stops and related processes and etchants useful for microelectronic and nanotechnology fabrication.
Claims9
A method for using Si--Ge--C in selective etch applications in conjunction with a silicon substrate, comprising:
- growing one or more epitaxial layers sequentially, starting at the silicon substrate, wherein at least one of the epitaxial layers comprises Si--Ge--C, wherein the carbon of the Si--Ge--C layer is about 4.5 atomic percent;
- and
- selectively etching the one or more layers adjacent to the Si--Ge--C layer and/or the Si--Ge--C layer wherein the selective etching includes applying a KOH etchant to the Si--Ge--C layer.
A method for using Si--Ge--C in selective etch applications in conjunction with a silicon, germanium, or silicon-germanium substrate, comprising:
- growing one or more epitaxial layers sequentially, starting at the substrate, at least one of which comprises Si--Ge--C, wherein carbon is present in the Si--Ge--C layer(s) in an amount sufficient for etch selectivity with respect to the substrate and/or adjacent epitaxial layers;
- and
- etching the one or more layers adjacent to the Si--Ge--C layer or the Si--Ge--C layer or the substrate with HNA, wherein the carbon content is greater than 2 percent.
A method of forming a silicon-on-insulator material, the method comprising the steps of:
- forming a Si--Ge--C epitaxial layer having a carbon concentration greater than 2 percent, sufficient to function as an etch-stop, wherein the Si--Ge--C resides on a surface of a first semiconductor silicon substrate;
- forming a second silicon epitaxial layer on the Si--Ge--C alloy layer;
- providing a first oxide layer on a surface of the second epitaxial layer;
- providing a second oxide layer on a second semiconductor silicon substrate;
- bringing into contact the first and second oxide layers thereby bonding together the first and second semiconductor substrates to thereby form a laminated structure;
- removing most of the first silicon substrate;
- exposing the laminate to a first etchant which preferentially etches the first silicon substrate until the remainder of the first silicon substrate is removed, but only a part of the Si--Ge--C layer is removed;
- and
- exposing the resultant structure to HNA which preferentially etches the Si--Ge--C layer for a time sufficient only to remove the remainder of the Si--Ge--C layer thereby producing a silicon-on-insulator material.
Dependencies are inferred from the claim text.