Patent ID: 11961766
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H  B | IPC H

Claim 10:
11. A method, comprising:
forming first and second epitaxial layers on a substrate;
forming a first gate structure with a first gate oxide structure on the first epitaxial layer; and
forming a second gate structure with a second gate oxide structure on the second epitaxial layer,
wherein forming the first and second gate oxide structures comprises:
forming first and second oxide layers of substantially equal thicknesses on the first and second epitaxial layers, respectively,
forming first and second nitride layers of different materials on the first and second oxide layers, respectively,
growing the first and second oxide layers to form modified first and second oxide layers with thicknesses different from each other,
removing the first and second nitride layers; and
forming a high-k dielectric layer on the modified first and second oxide layers.