Bulk FinFETs with body spacers for improving fin height variation

• A novel FinFET with body spacers in sub fin (BSSF) is proposed.
• Effective fin height variation induced in STI process is reduced.
• Lower Ion and Cg variations are verified by device simulation.

A novel FinFET structure with body spacers in sub fin (BSSF) is proposed to improve the fin height variation produced in the manufacturing processes. Device simulation results are presented to show the electrical variations improvement. The effective fin height (Heff) of FinFETs with BSSF is well controlled because it only depends on the silicon epi layer thickness (TSi). Taking advantage of the precisely controlled epitaxy process, Heff uniformity of FinFETs with BSSF is much better than conventional bulk FinFETs. Benefit from the smaller Heff variation, FinFETs with BSSF show much smaller electrical characteristics variation. For n-FinFETs, the Ion variation improves from 33.46% for conventional bulk FinFETs to 8.05% for FinFETs with BSSF. Additionally, manufacturing of FinFETs with BSSF is compatible with that of the state-of-the-art bulk FinFETs, promising for its applications in massive production.

The effective fin height (Heff) of FinFETs with BSSF is well controlled since it only depends on the silicon epi layer thickness (TSi). Taking advantage of the precise control of the epitaxy process, Heff uniformity of FinFETs with BSSF is much better than conventional bulk FinFETs. Benefit from the smaller Heff variation, FinFETs with BSSF show much smaller variation on transistor electrical characteristics.Figure optionsDownload as PowerPoint slide