Patent ID: 11889674
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 3:
4. A method, comprising:
providing a substrate comprising a first silicon layer, a first germanium layer over the first silicon layer, and a second silicon layer disposed over the first germanium layer;
forming a first fin structure over a first area of the substrate and a second fin structure over a second area of the substrate, the first fin structure comprising a first lower portion formed of the first silicon layer, a first middle portion formed of the first germanium layer, and a first top portion formed of the second silicon layer, the second fin structure comprising a second lower portion formed of the first silicon layer, a second middle portion formed of the first germanium layer, and a second top portion formed of the second silicon layer;
forming a patterned oxidation mask layer to cover an entirety of the second fin structure and a source/drain region of the first fin structure while a channel region of the first fin structure is exposed; and
after the forming of the patterned oxidation mask layer, oxidizing the channel region of the first fin structure to form a first oxide feature over sidewalls of the first lower portion, a second oxide feature over sidewalls of the first middle portion, and a third oxide feature over sidewalls of the first top portion.