Poly sandwich for deep trench fill
US9865691B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 2017 |
| Grant date | Jan 9, 2018 |
| Priority date | — |
| Expiry date | Jan 11, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D1/665
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A semiconductor device is formed by forming a deep trench in a substrate and a dielectric liner on sidewalls of the deep trench. A first undoped polysilicon layer is formed on the semiconductor device, extending into the deep trench on the dielectric liner, but not filling the deep trench. Dopants are implanted into the first polysilicon layer. A second layer of polysilicon is formed on the first layer of polysilicon. A thermal drive anneal activates and diffuses the dopants. In one version, the dielectric liner is removed at the bottom of the deep trench before the first polysilicon layer is formed, so that the polysilicon in the deep trench provides a contact to the substrate. In another version, the polysilicon in the deep trench is isolated from the substrate by the dielectric liner.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.