Charge pumping structure for a substrate bias generator
US4670669A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 13, 1984 |
| Grant date | Jun 2, 1987 |
| Priority date | — |
| Expiry date | Aug 13, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D89/215
Abstract
A charge pumping structure is disclosed for use in a substrate bias voltage generator. It includes a capacitor on a substrate region for coupling to a first node periodic voltage signals received at a second node. A first diode structure provides a current path from the first node to the substrate and a second diode structure provides a current path between the first node and a reference potential, which is typically the ground. The first diode structure includes a PN junction diode, an isolation ring for collecting minority charge carriers injected into the substrate and is constructed on a portion of the substrate that has a lower doping concentration than the underlying substrate portion establishing a built-in electric field which inhibits the flow of minority carriers from the first diode to the underlying substrate. The second diode structure may include a pocket type PN junction diode constructed so that majority carriers are prevented from moving back into the substrate from which the substrate bias voltage generator will have to remove them.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.