Air-spacer mos transistor
AssigneesSTMicroelectronics (Crolles 2) SAS, STMicroelectronics S.r.l., Commissariat A L'energie Atomique Et Aux Energies Alternatives
InventorsHeimanu Niebojewski, Yves Morand, Cyrille Le Royer, Olivier Rozeau
Life of this patent
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Abstract
A MOS transistor has a gate insulator layer that is made of a material of high dielectric constant deposited on a substrate. The gate insulator layer extends, with a constant thickness, under and beyond a gate stack. Spacers of low dielectric constant are formed on either side of the gate stack and vertically separated from the substrate by the extension of the gate insulator layer beyond the sides of the gate stack. The spacers of low dielectric constant are preferably air spacers.
Claims18
A MOS transistor, comprising a gate insulator layer made of a material of high dielectric constant which extends, with a constant thickness, under and in contact with air spacers delimited by a layer of a dielectric material present on sides of a conductive gate stack.
A method for manufacturing a MOS transistor, comprising:
- depositing on a substrate a gate insulator layer of high dielectric constant;
- successively depositing materials to form a gate conductor stack;
- delimiting the conductive gate stack while leaving in place the gate insulator layer;
- forming around the conductive gate stack first sacrificial spacers;
- and
- etching the gate insulator by using the first sacrificial spacers and the conductive gate stack as a mask.
A MOS transistor, comprising:
- a substrate including a source region and a drain region with a substrate region between the source and drain regions;
- a gate insulator layer extending on top of the substrate region and at least partially on top of the source and drain regions, the gate insulator layer made of a material of high dielectric constant and having a constant thickness;
- a gate stack on top of the gate insulator layer above the substrate region;
- a protection layer on sides of the gate stack and on top of the gate insulator layer;
- and
- air spacers of low dielectric constant on either side of the gate stack and vertically separated from the substrate by the gate insulator layer and the protection layer and delimited by a layer of dielectric material present on sides of the gate stack.
A method, comprising:
- depositing a gate insulator layer of high dielectric constant on top of a substrate;
- forming a gate stack on top of the gate insulator layer, the gate insulator layer extending laterally beyond side edges of the gate stack;
- conformally depositing a protection layer on the gate insulator layer and side edges of the gate stack;
- forming air spacers of low dielectric constant on either side of the gate stack, said spacers vertically separated from the substrate by the protection layer and the gate insulator layer and delimited by the protection layer.
Dependencies are inferred from the claim text.