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US 7,332,439 B2Granted
Metal gate transistors with epitaxial source and drain regions
AssigneeIntel Corporation
InventorsNick Lindert, Justin K. Brask, Andrew Westmeyer
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Abstract
An MOS transistor formed on a heavily doped substrate is described. Metal gates are used in low temperature processing to prevent doping from the substrate from diffusing into the channel region of the transistor.
Claims14
A semiconductor process comprising:
- growing an un-doped or lightly doped silicon layer on a heavily doped substrate;
- forming an insulating layer on the silicon layer;
- forming sacrificial polysilicon gates on the insulating layer;
- etching the silicon layer and undercutting the gates so as to form silicon channel regions under the polysilicon gates;
- growing source and drain regions from the substrate which extend into the undercutting adjacent to the silicon channel regions;
- removing the polysilicon gates;
- and
- forming metal gates in place of the polysilicon gates.
5 more elements
A process for forming complementary transistors comprising:
- forming a lightly doped or un-doped monocrystalline layer on a heavily doped monocrystalline substrate;
- forming temporary polysilicon gates insulated from the monocrystalline layer;
- etching the monocrystalline layer to form channel regions for the transistors, undercutting the polysilicon gates;
- growing a first plurality of monocrystalline source and drain regions doped with an n-type dopant, extending from opposite sides of a first plurality of the channel regions including within the undercutting of the polysilicon gates disposed above the first plurality of source and drain regions;
- growing a second plurality of monocrystalline source and drain regions doped with a p-type dopant, extending from opposite sides of a second plurality of the channel regions including within the undercutting of the polysilicon gates disposed above the second plurality of source and drain regions;
- replacing the polysilicon gates associated with the first plurality of source and drain regions with a first metal;
- and
- replacing the polysilicon gates associated with the second plurality of source and drain regions with a second metal.
5 more elements
Dependencies are inferred from the claim text.