Method for making planar 3D heterepitaxial semiconductor structures with buried epitaxial silicides
AssigneeInternational Business Machines Corporation
InventorKing-Ning Tu
Life of this patent
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Abstract
A 3D epitaxial structure is described in which metal compounds are formed in a semiconductor layer, the metal compounds being epitaxial with the semiconductor layer and having a top surface which is planar with the top surface of the semiconductor layer. Onto this another layer can be epitaxially grown, such as an additional semiconductor layer. The technique for forming such a structure utilizes a starting material for metal compound formation which leaves a residue that is preferentially etched in order to preserve the embedded metal compound and to leave a substantially planar surface comprising the metal compound epitaxial regions and the unreacted surface regions of the semiconductor layer.
Claims24
A method for forming a 3D , epitaxial structure, comprising the steps of:
- providing a first layer of a single crystal semiconductor material,
- forming a layer comprised of a composition including at least elements A and B on at least a portion of said first layer, element A being capable of forming a compound with said semiconductor material that is epitaxial with said semiconductor material, element B being chosen as one which does not readily form a compound with said semiconductor material at the temperatures and times used in a heating step to form said epitaxial compound of element A and said semiconductor,
- heating said composition and said first said semiconductor layer to form said epitaxial compound in said semiconductor layer, the residue of said composition after said heating step being capable of being etched without undue etching of said epitaxial compound, said epitaxial compound forming an etch stop,
- removing said residue by etching to the surface of said epitaxial compound, thereby producing a planar surface comprised of the top surface of said epitaxial compound and the unreacted surface portion of said first layer of semiconductor material, and
- epitaxially forming a top layer of single crystal material over said epitaxial compound and said first layer of semiconductor material.
A method for forming a 3D , epitaxial structure including the steps of:
- depositing onto at least a portion of a single crystal substrate a layer having a composition including at least two elements capable of being decoupled from one another when heated at given conditions of temperature and time, one of said elements then forming a compound with said substrate which is epitaxial therewith and embedded therein while the other elements in said composition does not readily form a compound with said substrate when heated at said given conditions of temperature and time,
- heating said layer at said given conditions of temperature and time to decouple said elements and to form said epitaxial compound embedded in the surface of said substrate, said compound having a top surface which is substantially planar with the top surface of said substrate, the remainder of said composition left on the surface of said substrate after said heating step being removeable without substantially removing said epitaxial compound,
- removing said remainder of said composition by reactively etching it, said removal continuing until the surface of said epitaxial compound is exposed, said compound acting as an etch stop to leave a substrate having an embedded epitaxial compound region therein and a planar top surface, and
- epitaxially growing a single crystal top layer onto at least said epitaxial compound region.
A method for making a 3D, epitaxial structure, comprising the steps of:
- depositing a starting layer onto a single crystal semiconductor layer, said starting layer including at least two elements, one of which can react with said semiconductor to produce a compound which is epitaxial therewith and embedded in said semiconductor,
- forming said epitaxial compound embedded in said semiconductor, said compound having a top surface which is substantially planar with the top surface of said semiconductor layer, there being a residue of said starting layer left on said epitaxial compound after said compound is formed,
- removing said residue and leaving said embedded compound whose top surface is substantially planar with the top surface of said semiconductor layer, and
- epitaxially forming a single crystal top layer on said planar surface.
Dependencies are inferred from the claim text.