FinFET with a silicon germanium alloy channel and method of fabrication thereof
AssigneeInternational Business Machines Corporation
InventorsKangguo Cheng, Bruce B. Doris, Hong He, Ali Khakifirooz
Life of this patent
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Abstract
A gate cavity is formed exposing a portion of a silicon fin by removing a sacrificial gate structure that straddles the silicon fin. An epitaxial silicon germanium alloy layer is formed within the gate cavity and on the exposed portion of the silicon fin. Thermal mixing or thermal condensation is performed to convert the exposed portion of the silicon fin into a silicon germanium alloy channel portion which is laterally surrounded by silicon fin portions. A functional gate structure is formed within the gate cavity providing a finFET structure having a silicon germanium alloy channel portion which is laterally surrounded by silicon fin portions.
Claims19
A method of forming a semiconductor structure comprising:
- forming a sacrificial gate structure straddling a portion of a silicon fin;
- forming a dielectric material over said silicon fin and having a topmost surface that is coplanar with a topmost surface of said sacrificial gate structure;
- removing said sacrificial gate structure to provide a gate cavity exposing a portion of said silicon fin;
- converting said exposed portion of said silicon fin into a silicon germanium alloy channel portion, wherein said converting said exposed portion of said silicon fin into said silicon germanium alloy channel portion comprises epitaxially depositing a silicon germanium alloy layer within said gate cavity and directly on said exposed portion of said silicon fin, and performing a thermal condensation process;
- and
- providing a functional gate structure in said gate cavity and in direct contact with said silicon germanium alloy channel portion.
A method of forming a semiconductor structure comprising:
- forming a sacrificial gate structure straddling a portion of a silicon fin;
- forming a dielectric material over said silicon fin and having a topmost surface that is coplanar with a topmost surface of said sacrificial gate structure;
- removing said sacrificial gate structure to provide a gate cavity exposing a portion of said silicon fin;
- converting said exposed portion of said silicon fin into a silicon germanium alloy channel portion, said silicon germanium alloy channel portion is located laterally between a silicon fin source portion and a silicon fin drain portion;
- providing a functional gate structure in said gate cavity and in direct contact with said silicon germanium alloy channel portion;
- and
- forming a raised source region in direct contact with said silicon fin source portion and a raised drain region located in direct contact with said silicon fin drain portion after providing said functional gate structure.
A method of forming a semiconductor structure comprising:
- forming a sacrificial gate structure straddling a portion of a silicon fin;
- forming a dielectric material over said silicon fin and having a topmost surface that is coplanar with a topmost surface of said sacrificial gate structure;
- removing said sacrificial gate structure to provide a gate cavity exposing a portion of said silicon fin;
- converting said exposed portion of said silicon fin into a silicon germanium alloy channel portion;
- forming a dielectric spacer along sidewalls of said gate cavity;
- and
- providing a functional gate structure in said gate cavity and in direct contact with said silicon germanium alloy channel portion, wherein said providing said functional gate structure comprises depositing a gate dielectric and a gate conductor, and said gate dielectric is U-shaped and has topmost surfaces that are coplanar with a topmost surface of said gate conductor and said gate conductor has sidewall surfaces that directly contact a vertical portion of said U-shaped gate dielectric.
Dependencies are inferred from the claim text.