CPC H01L 29/4991 (2013.01) [H01L 21/76834 (2013.01); H01L 21/823468 (2013.01); H01L 21/823475 (2013.01); H01L 21/823864 (2013.01); H01L 29/41725 (2013.01); H01L 29/495 (2013.01); H01L 29/6653 (2013.01); H01L 29/66545 (2013.01); H01L 29/6656 (2013.01); H01L 29/66636 (2013.01); H01L 29/66689 (2013.01); H01L 29/78 (2013.01); H01L 21/823425 (2013.01); H01L 29/4966 (2013.01); H01L 29/513 (2013.01); H01L 29/517 (2013.01)] | 20 Claims |
1. A device comprising:
a gate stack disposed on a substrate, the gate stack including a u-shaped gate dielectric layer and a fill material at least partially surrounded by the u-shaped gate dielectric layer;
a first sidewall spacer disposed on a side surface of the gate stack, wherein the first sidewall spacer is formed of a porous low-k dielectric material; and
a second sidewall spacer disposed between the first sidewall spacer and the gate stack such that the second sidewall spacer interfaces with the u-shaped gate dielectric layer,
wherein a bottom surface of the first sidewall spacer is spaced apart from the substrate by a portion of the second sidewall spacer.
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