Semiconductor structure with reduced junction leakage and method of fabrication thereof
First Claim
1. A method for forming a facet free field effect transistor structure using selective epitaxial deposition, comprising:
- providing a substrate;
epitaxially growing, over distinct areas of the substrate, a plurality of first epitaxial screen layers for a plurality of field effect transistors, the respective first epitaxial screen layers having defined dopant concentrations and grown to preselected thicknesses;
epitaxially growing, over distinct areas of the first epitaxial screen layers, a plurality of second epitaxial channel layers, the respective second epitaxial channel layers being undoped and grown to preselected thicknesses;
wherein at least some of the epitaxially grown layers form facets that are eliminated during processing.
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Abstract
A semiconductor structure is formed with a NFET device and a PFET device. The NFET device is formed by masking the PFET device regions of a substrate, forming a screen layer through epitaxial growth and in-situ doping, and forming an undoped channel layer on the screen layer through epitaxial growth. The PFET device is similarly formed by masking the NFET regions of a substrate, forming a screen layer through epitaxial growth and in-situ doping, and forming an undoped channel layer on the screen layer through epitaxial growth. An isolation region is formed between the NFET and the PFET device areas to remove any facets occurring during the separate epitaxial growth phases. By forming the screen layer through in-situ doped epitaxial growth, a reduction in junction leakage is achieved versus forming the screen layer using ion implantation.
501 Citations
18 Claims
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1. A method for forming a facet free field effect transistor structure using selective epitaxial deposition, comprising:
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providing a substrate; epitaxially growing, over distinct areas of the substrate, a plurality of first epitaxial screen layers for a plurality of field effect transistors, the respective first epitaxial screen layers having defined dopant concentrations and grown to preselected thicknesses; epitaxially growing, over distinct areas of the first epitaxial screen layers, a plurality of second epitaxial channel layers, the respective second epitaxial channel layers being undoped and grown to preselected thicknesses; wherein at least some of the epitaxially grown layers form facets that are eliminated during processing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An intermediate die structure for a field effect transistor, comprising:
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a substrate; a plurality of areas temporarily protecting portions of the substrate from having deposited thereon a single crystal silicon material; a plurality of first epitaxial screen layers deposited on the substrate and defined between the plurality of areas, the respective first epitaxial screen layers having defined dopant concentrations and preselected thickness; a plurality of second epitaxial channel layers, the respective second epitaxial channel layers having no facets, configured to be undoped, and to have preselected thicknesses, the plurality of second epitaxial channel layers being disposed on the plurality of first epitaxial screen layers; a blanket epitaxial layer positioned above the substrate. - View Dependent Claims (14, 15)
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16. A facet free channel structure for a field effect transistor, comprising:
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a substrate; a plurality of first screen layers deposited on the substrate, the respective first screen layers having defined dopant concentrations and preselected thicknesses; and a plurality of second epitaxial channel layers, the respective second epitaxial channel layers having no facets, being substantially undoped, and having preselected thicknesses, the plurality of second epitaxial channel layers being selectively deposited on the plurality of first screen layers; wherein the first screen layers are part of a blanket epitaxial layer positioned above the substrate. - View Dependent Claims (17, 18)
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Specification