Method for suppressing boron penetration in PMOS with nitridized polysilicon gate
US5567638A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 14, 1995 |
| Grant date | Oct 22, 1996 |
| Priority date | — |
| Expiry date | Jun 14, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D64/662
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for suppressing boron penetration in a PMOS with a nitridized polysilicon gate includes steps of 1) growing a layer of gate oxide on a substrate, 2) forming at least one first polysilicon layer on the gate oxide layer, 3) nitridizing the first polysilicon layer, 4) forming a second polysilicon layer on the first polysilicon layer; and 5) implanting B-containing ions into the first and second polysilicon layers for constructing a PMOS structure wherein the nitridizing step suppresses a boron ion from penetration into the substrate. The present invention is characterized in nitridation on a polysilicon gate instead of a gate oxide which can effectively suppress boron penetration, avoid drawbacks resulting from nitridizing a gate oxide, and moreover, improve the reliability of the device owing to the slight nitridation effect in the polysilicon gate and the gate oxide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.