Fabrication of complementary field-effect transistors each having multi-part channel
US5744372A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 1, 1995 |
| Grant date | Apr 28, 1998 |
| Priority date | — |
| Expiry date | Jun 1, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D84/859
Abstract
Each of a pair of complementary insulated-gate field-effect transistors is manufactured in an asymmetric lightly doped drain structure that enables the source characteristics to be decoupled from the drain characteristics. Each transistor has a multi-part channel formed with an output portion, which adjoins the drain zone, and a more heavily doped input portion, which adjoins the source zone. The drain zone of each transistor contains a main portion and a more lightly doped extension that meets the output channel portion. The drain extension of each transistor typically extends at least as far below the upper semiconductor surface as the main drain portion so as to help reduce hot-carrier effects. The input channel portion of each transistor is situated in a threshold body zone whose doping determines the threshold voltage. Importantly, the provision of lightly doped source extensions is avoided so that improving the drain characteristics does not harm the source characteristics, and vice versa. In fabricating the complementary transistor structure, the threshold body zone of each transistor is formed at the same time as the drain extension of the other transistor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.