P-MOSFETS with enhanced anomalous narrow channel effect
US5559050A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1994 |
| Grant date | Sep 24, 1996 |
| Priority date | — |
| Expiry date | Jun 30, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D84/854
Abstract
An anomalous threshold voltage dependence on channel width measured on 0.25 .mu.m ground rule generation trench-isolated buried-channel p-MOSFETs is used to enhance circuit performance. As the channel width is reduced, the magnitude of the threshold voltage first decreases before the onset of the expected sharp rise in V.sub.t for widths narrower than 0.4 .mu.m. Modeling shows that a "boron puddle" is created near the trench bounded edge as a result of transient enhanced diffusion (TED) during the gate oxidation step, which imposes a penalty on the off-current of narrow devices. TED is governed by interstitials produced by a deep phosphorus implant, used for latchup suppression, diffusing towards the trench sidewall and top surface of the device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.