Strained Si based layer made by UHV-CVD, and devices therein
AssigneeInternational Business Machines Corporation
InventorsJack O. Chu, Khaled Ismail
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Abstract
A method for fabricating a strained Si based layer, devices manufactured in this layer, and electronic systems comprising such layers and devices are disclosed. The method comprises the steps of growing epitaxially a SiGe layer on a substrate, and creating a varying Ge concentration in this SiGe layer. The Ge concentration in the SiGe layer includes a unique Ge overshoot zone, where the Ge concentration is abruptly and significantly increased. The Si based layer is epitaxially deposited onto the SiGe layer, whereby is becomes tensilely strained. It is also disclosed that the strained Si based layer, typically Si or SiGe, can be transferred to a different bulk substrate, or to an insulator.
Claims27
A method for fabricating a strained Si based layer comprising the steps of:
- growing epitaxially a SiGe layer on a substrate, wherein creating a varying Ge concentration in the thickness direction of said SiGe layer, said Ge concentration having a first value at the interface with said substrate and having a second value at full thickness of said SiGe layer, said second value of Ge concentration being larger than said first value of Ge concentration, furthermore said SiGe layer imbedding a Ge overshoot zone, wherein said Ge overshoot zone having a third value of Ge concentration, said third value being larger than said second value;
- depositing epitaxially said Si based layer onto said SiGe layer;
- and
- transferring said strained Si based layer onto a second substrate.
A method for fabricating a strained Si based layer on an insulator comprising the steps of:
- growing epitaxially a SiGe layer on a substrate, wherein creating a varying Ge concentration in the thickness direction of said SiGe layer, said Ge concentration having a first value at the interface with said substrate and having a second value at full thickness of said SiGe layer, said second value of Ge concentration being larger than said first value of Ge concentration, furthermore said SiGe layer imbedding a Ge overshoot zone, wherein said Ge overshoot zone having a third value of Ge concentration, said third value being larger than said second value;
- depositing epitaxially said Si based layer onto said SiGe layer;
- and
- transferring said strained Si based layer onto said insulator.
Dependencies are inferred from the claim text.