Method for reduced N+ diffusion in strained Si on SiGe substrate
AssigneeInternational Business Machines Corporation
InventorsDureseti Chidambarrao, Omer H. Dokumaci
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Abstract
The first source and drain regions are formed in an upper surface of a SiGe substrate. The first source and drain regions containing an N type impurity. Vacancy concentration in the first source and drain regions are reduced in order to reduce diffusion of the N type impurity contained in the first source and drain regions. The vacancy concentration is reduced by an interstitial element or a vacancy-trapping element in the first source and drain regions. The interstitial element or the vacancy-trapping element is provided by ion-implantation.
Claims20
A method for reducing diffusion of an N type impurity in a SiGe-based substrate, the method comprising steps of:
- forming source and drain extension regions in an upper surface of the SiGe-based substrate;
- and
- ion implanting an interstitial element into the source and drain extension regions to reduce vacancy concentration in the source and drain extension regions and to form low-vacancy regions that substantially overlap the source and drain extension regions.
A method for reducing diffusion of an N type impurity in a SiGe substrate, the method comprising steps of:
- forming an Si cap layer on the SiGe substrate;
- forming a gate electrode on the Si cap layer;
- forming sidewalls on sides of the gate electrode;
- forming source and drain extension regions in an upper surface of the SiGe-based substrate;
- and
- ion implanting an interstitial element into the source and drain extension regions to reduce vacancy concentration in the source and drain extension regions,
- wherein the ion implanting occurs after the sidewalls are formed.
A method for reducing diffusion of an N type impurity in a SiGe substrate, the method comprising steps of:
- forming an Si cap layer on the SiGe substrate;
- forming a gate electrode on the Si cap layer;
- forming sidewalls on sides of the gate electrode;
- forming source and drain extension regions in an upper surface of the SiGe substrate;
- and
- reducing a vacancy concentration in the source and drain extension regions using ion implantation in order to annihilate excess vacancies or trap vacancies,
- wherein the reducing occurs after the sidewalls are formed and forms low-vacancy regions that substantially overlap the source and drain extension regions.
Dependencies are inferred from the claim text.