Patent ID: 7172935

Claim:
A method of fabricating semiconductor devices, the method comprising the steps of: (a) providing a substrate; (b) fabricating a first semiconductor device on the substrate, the device comprising at least one first strained channel region and a first gate insulator having first thickness, the step comprising: (i) growing an intermediate portion of the first gate insulator on the substrate by thermal oxidation, and (ii) depositing a predetermined amount of a dielectric material over the intermediate portion of the first gate insulator thereby increasing thickness thereof to the first thickness; (c) fabricating a second semiconductor device on the substrate, the device comprising and at least one second strained channel region a second gate insulator having second thickness different from the first thickness, the step comprising: (i) removing the first gate insulator in a first area of the substrate, and (ii) forming the second gate insulator in the first area thereover, wherein thickness of at least one of said the first and second strained channel regions is substantially unchanged following the fabrication of the semiconductor devices.