Chevron cmos trigate structure
AssigneeInternational Business Machines Corporation
InventorsBrent Anderson, Edward Nowak
Life of this patent
Estimating the term…
Abstract
Disclosed herein is a structure with two different type tri-gate MOSFETs formed on the same substrate. Each MOSFET comprises a fin with optimal mobility for the particular type of MOSFET. Due to the processes used to form fins with different crystalline orientations on the same substrate, one of the MOSFETs has a fin with a lower mobility top surface. To inhibit inversion of the top surface, this MOSFET has a gate dielectric layer with a thicker region on the top surface than it does on the opposing sidewall surfaces. Additionally, several techniques for forming the thicker region of the gate dielectric layer are also disclosed.
Claims18
A method of forming a field effect transistor:
- forming a semiconductor fin with opposing sidewall surfaces having a first crystalline orientation and a top surface having a second crystalline orientation, wherein said second crystalline orientation has a lesser mobility for said field effect transistor than said first crystalline orientation;
- and
- forming a gate dielectric layer on said top surface and on said opposing sidewall surfaces of said semiconductor fin, wherein said forming of said gate dielectric layer comprises:
- forming a first region of said gate dielectric layer on said top surface of said semiconductor fin;
- and
- forming second regions of said gate dielectric layer on said opposing sidewall surfaces of said semiconductor fin such that a first thickness of said first region is greater than a second thickness of said second regions.
A method of forming a semiconductor structure, said method comprising:
- simultaneously forming a first semiconductor fin for a first-type field effect transistor and a second semiconductor fin for a second-type field effect transistor,
- wherein said first semiconductor fin is formed with opposing sidewall surfaces having a first crystalline orientation and a top surface having a second crystalline orientation,
- wherein said second semiconductor fin is formed with said second crystalline orientation, and
- wherein said second crystalline orientation has a lesser mobility for said first-type field effect transistor than said first crystalline orientation;
- and
- forming a gate dielectric layer on said top surface and on said opposing sidewall surfaces of said first semiconductor fin, wherein said forming of said gate dielectric layer comprises:
- forming a first region of said gate dielectric layer on said top surface of said first semiconductor fin;
- and
- forming second regions of said gate dielectric layer on said opposing sidewall surfaces of said first semiconductor fin such that a first thickness of said first region is greater than a second thickness of said second regions.
A method of forming a field effect transistor:
- forming a semiconductor fin with opposing sidewall surfaces having a first crystalline orientation and a top surface having a second crystalline orientation, wherein said second crystalline orientation has a lesser mobility for said field effect transistor than said first crystalline orientation;
- and
- forming a gate dielectric layer on said top surface and on said opposing sidewall surfaces of said semiconductor fin, wherein said forming of said gate dielectric layer comprises:
- forming a first region of said gate dielectric layer on said top surface of said semiconductor fin;
- forming second regions of said gate dielectric layer on said opposing sidewall surfaces of said semiconductor fin such that a first thickness of said first region is greater than a second thickness of said second regions;
- and
- forming a tri-gate on said gate dielectric layer, wherein said tri-gate is adjacent to said top surface and said opposing sidewalls.
Dependencies are inferred from the claim text.