| CPC H01L 21/02532 (2013.01) [H01L 21/0262 (2013.01); H01L 21/76251 (2013.01); H10F 30/223 (2025.01); H10F 71/1212 (2025.01); H10F 77/147 (2025.01)] | 20 Claims |
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1. A method for forming a semiconductor device, comprising:
providing a silicon-on-insulator (SOI) substrate;
forming an N-type drift region and a P-type drift region spaced from each other and in the SOI substrate;
forming an N-type contact region and a P-type contact region inset respectively into the N-type and P-type drift regions;
depositing a passive cap over the SOI substrate, the passive cap having a larger dielectric constant than an insulating layer of the SOI substrate, wherein the passive cap overlies and directly contacts individual top surfaces of the N-type and P-type contact regions and individual top surfaces of the N-type and P-type drift regions;
etching the SOI substrate according to the passive cap to form a trench extending from an upper surface of the SOI substrate into an active region of the SOI substrate, wherein the trench exposes individual sidewalls of the N-type and P-type drift regions, only partially overlies the N-type and P-type drift regions, and is spaced from the N-type and P-type contact regions respectively by the N-type and P-type drift regions; and
depositing a semiconductor layer to fill the trench, wherein the semiconductor layer comprises a semiconductor material of a different type than silicon of the SOI substrate and partially forms a photodetector;
wherein the depositing of the passive cap comprises performing a low-pressure chemical vapor deposition (LPCVD) using a precursor comprising hexachlorodisilane (HCD), wherein the passive cap comprises hydrogen, and wherein an atomic percentage of hydrogen in the passive cap is greater than approximately 10%.
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