Process for polysilicon thin film transistors using backside irradiation and plasma doping
US5602047A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 1996 |
| Grant date | Feb 11, 1997 |
| Priority date | — |
| Expiry date | Jun 13, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D86/60
Abstract
The source-to-drain gap in a TFT is formed by exposing a positive photoresist from the back side of the substrate, using the gate as an optical mask. The resulting photoresist mask then protects the underlying amorphous silicon while the structure is exposed to a gaseous plasma that includes dopant material. Heavily doped regions are thus formed, leaving a gap that is in perfect alignment with the gate. After removal of the photoresist, the structure is given a laser anneal which results both in the crystallization of the amorphous silicon into polysilicon as well as a more even distribution of the dopant material. The structure is completed in the usual way by providing a passivation layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.