Method of fabricating mobility enhanced CMOS devices
First Claim
Patent Images
1. A method of forming a semiconductor structure comprising steps of:
- forming spacer voids between a gate a mandrel layer;
creating recesses in a substrate below and in alignment with the spacer voids;
filling a first portion of the recesses with a stress imposing material;
filling a second portion of the recesses with a semiconductor material; and
removing the mandrel layer.
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Abstract
Compressive or tensile materials are selectively introduced beneath and in alignment with spacer areas and adjacent to channel areas of a semiconductor substrate to enhance or degrade electron and hole mobility in CMOS circuits. A process entails steps of creating dummy spacers, forming a dielectric mandrel (i.e., mask), removing the dummy spacers, etching recesses into the underlying semiconductor substrate, introducing a compressive or tensile material into a portion of each recess, and filling the remainder of each recess with substrate material.
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Citations
41 Claims
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1. A method of forming a semiconductor structure comprising steps of:
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forming spacer voids between a gate a mandrel layer; creating recesses in a substrate below and in alignment with the spacer voids; filling a first portion of the recesses with a stress imposing material; filling a second portion of the recesses with a semiconductor material; and removing the mandrel layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of forming a semiconductor structure comprising steps of:
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forming dummy spacers on sides of a gate formed on a substrate; forming a mandrel layer with portions of the mandrel layer abutting the dummy spacers; removing the dummy spacers to form spacer voids between the gate and the mandrel layer; creating recesses in the substrate below and in alignment with the spacer voids filling a first portion of the recesses with a stress imposing material; and filling a second portion of the recesses with a semiconductor material. - View Dependent Claims (20, 21, 22)
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23. A method of forming a semiconductor structure comprising steps of:
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forming a field effect transistor gate on a substrate; forming a first dummy spacer and a second dummy spacer on sides of the field effect transistor gate; forming a mandrel layer with portions of the mandrel layer abutting the first and second dummy spacers for the field effect transistor gate; after masking the semiconductor structure, introducing stress to the field effect transistor gate; and removing the mandrel layer, wherein the step of introducing stress material comprises; removing the first and second dummy spacers from the field effect transistor gate to form first and second spacer voids between the field effect transistor gate and the portions of the mandrel layer; creating a first recess in the substrate below and in alignment with the first spacer void and a second recess in the substrate below and in alignment with the second spacer void for the field effect transistor gate; filling a first portion of the first recess and a first portion of the second recess with a stress imposing material configured to enhance performance of the field effect transistor gate; filling a second portion of the first recess and a second portion of the second recess for the field effect transistor gate with a semiconductor material; and unmasking the semiconductor structure. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31)
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32. A method of providing compressive or tensile imposing materials selectively beneath and in alignment with spacer areas of a semiconductor substrate and adjacent to channel areas to enhance electron and hole mobility in CMOS circuits, comprising:
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forming disposable dummy spacers on the semiconductor substrate and adjacent to the channel areas of a patterned gate; forming a mandrel over active device regions of the patterned gate, abutting the disposable dummy spacers; after forming of the mandrel, removing the disposable dummy spacers to form spacer voids; etching recesses into the semiconductor substrate at a bottom of the spacer voids; introducing a compressive or tensile imposing material into a portion of the recesses; and filling a remainder of the recesses with material. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41)
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Specification