Semiconductor device with localized carrier lifetime reduction and fabrication method thereof
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsAlex Kalnitsky, Chih-Wen Yao, Jun Cai, Ruey-Hsin Liu, Hsiao-Chin Tuan
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Abstract
A method of fabricating a semiconductor structure includes forming an isolation feature in a substrate, removing a portion of the isolation feature and a portion of the substrate underneath the removed portion of the isolation feature to form a trench in the substrate, and forming a trapping feature around a bottom portion of the trench. A first sidewall and a second sidewall of the trench are in direct contact with the isolation feature, and a bottom surface of the trench is below a bottom surface of the isolation feature.
Claims16
A method of fabricating a semiconductor structure, the method comprising:
- forming an isolation feature in a substrate;
- removing a portion of the isolation feature and a portion of the substrate underneath the removed portion of the isolation feature to form a trench in the substrate, wherein a first sidewall and a second sidewall of the trench are in direct contact with the isolation feature and a bottom surface of the trench is below a bottom surface of the isolation feature;
- forming a trapping feature around a bottom portion of the trench, wherein at least a portion of the trapping feature directly contacts the substrate, and a portion of the first sidewall or the second sidewall below the isolation feature, and the forming the trapping feature around the bottom portion of the trench comprises:
- epitaxially growing at least one of a germanium film, a silicon germanium film or a graphene film on the bottom surface of the trench;
- depositing a dielectric layer along the first sidewall, the second sidewall and the bottom surface of the trench;
- and
- removing a portion of the dielectric layer to expose the bottom surface of the trench.
A method of manufacturing a power device, the method comprising:
- forming a first shallow trench isolation (STI) feature and a second STI feature in a substrate;
- depositing a pad oxide layer over the first STI and the second STI;
- depositing a silicon nitride layer over the pad oxide layer;
- patterning the silicon nitride layer to form a first deep trench in the first STI and a second deep trench in the second STI, wherein an upper portion of the first deep trench is in contact with the first STI and a lower portion of the first deep trench is in contact with the substrate, and an upper portion of the second trench is in contact with the second STI and a lower portion of the second deep trench is in contact with the substrate;
- forming a trapping feature at a bottom portion of the first deep trench and at a bottom portion of the second deep trench, wherein the forming the trapping feature around the bottom portion of the trench comprises:
- epitaxially growing at least one of a germanium film, a silicon germanium film or a graphene film on a bottom surface of the first deep trench;
- depositing a dielectric layer along a first sidewall, a second sidewall and the bottom surface of the first deep trench;
- and
- removing a portion of the dielectric layer to expose the bottom surface of the first trench;
- and
- filling the first deep trench and the second deep trench with an insulating material, wherein the trapping feature directly contacts the insulating material and directly contacts the substrate.
A method of fabricating a high-voltage device, comprising:
- forming a first shallow trench isolation (STI) feature in a substrate;
- forming a deep trench in the first STI feature, wherein sidewalls of the first deep trench are between sidewalls of the first STI;
- implanting species to introduce lattice defects and strains in the substrate at a bottom portion of the deep trench;
- epitaxially growing at least one of a germanium film, a silicon germanium film or a graphene film on a bottom surface of the deep trench;
- depositing a dielectric layer along a first sidewall, a second sidewall and the bottom surface of the deep trench;
- and
- removing a portion of the dielectric layer to expose the bottom surface of the deep trench;
- and
- filling the deep trench with silicon oxide after the implanting of the species.
Dependencies are inferred from the claim text.