Stacked nanosheet device with step configuration where the bottom nanosheet stack is wider than the top nanosheet stack
AssigneeInternational Business Machines Corporation
InventorsTsung-Sheng Kang, Tao Li, Ruilong Xie, Alexander Reznicek
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Abstract
An etch stop layer is provided in a vertical stack containing a bottom material stack and a top material stack. Notably, the etch stop layer is provided in an area in which a step region is desired and thus during the etch use to provide the step region the etch stops on the etch stop layer without tapering or compromising the height of the top material stack. Also, prior to gate formation, a dielectric oxide is formed in an area in proximity to the nanosheet step region and a portion thereof remains in the structure after nanosheet and functional gate structure formation.
Claims17
A semiconductor structure comprising:
- a bottom nanosheet device comprising a bottom stack of spaced apart bottom device semiconductor channel material nanosheets, each bottom device semiconductor channel material nanosheet of the bottom stack of spaced apart bottom device semiconductor channel material nanosheets has a first width;
- a top nanosheet device located above the bottom nanosheet device and comprising a top stack of spaced apart top device semiconductor channel material nanosheets, wherein each top device semiconductor channel material nanosheet of the top stack of spaced apart top device semiconductor channel material nanosheets, has a second width, wherein the first width is greater than the second width and the bottom stack of spaced apart bottom device semiconductor channel material nanosheets and the top stack of spaced apart top device semiconductor channel material nanosheets are arranged in a step configuration;
- a dielectric oxide structure located between the bottom nanosheet device and the top nanosheet device, wherein the dielectric oxide structure is spaced apart from a bottommost top device semiconductor channel nanosheet and a topmost bottom device semiconductor channel nanosheet;
- and
- a bottom-top device separating inner spacer located between the top nanosheet device and the bottom nanosheet device, wherein the bottom-top device separating inner spacer has a first sidewall that is vertically aligned to a first sidewall of the top stack of spaced apart top device semiconductor channel material nanosheets, and a second sidewall opposite the first sidewall, that is in direct physical contact with a first sidewall of the dielectric oxide structure, wherein the dielectric oxide structure includes a second sidewall that is opposite the first sidewall of the dielectric oxide structure that is vertically aligned with a second sidewall of the top stack of spaced apart top device semiconductor channel material nanosheets, wherein the second sidewall of the top stack of spaced apart top device semiconductor channel material nanosheets is opposite the first sidewall of the top stack of spaced apart top device semiconductor channel material nanosheets.
Dependencies are inferred from the claim text.