Method of forming retrograde well structures and punch-through barriers using low energy implants
US5963801A · kind A · utility
46Cited by
11References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 19, 1996 |
| Grant date | Oct 5, 1999 |
| Priority date | — |
| Expiry date | Dec 19, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D84/038
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A retrograde well in a CMOS device is formed by using a low energy ion implanter. Dopant atoms are implanted into a bare surface of the device's substrate, in a direction that is orthogonal to the surface of the substrate (for a substrate having a <100> orientation). The well implant can be performed at an energy below 220 keV. Chained implants for a punch-through barrier in the retrograde well can be performed after the well implant. When the substrate is annealed, the punch-through barrier is activated at the same time as the retrograde well.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.