CONFIGURATION AND FABRICATION OF SEMICONDUCTOR STRUCTURE HAVING EXTENDED-DRAIN FIELD-EFFECT TRANSISTOR

摘要

An extended-drain insulated-gate field-effect transistor (104 or 106) contains first and second source/drain zones 324 and 184B or 364 and 186B) laterally separated by a channel (322 or 362) zone constituted by part of a first well region (184A or 186A). A gate dielectric layer (344 or 384) overlies the channel zone. A gate electrode (346 or 386) overlies the gate dielectric layer above the channel zone. The first source/drain zone is normally the source. The second S/D zone, normally the drain, is constituted with a second well region (184B or 186B). A well-separating portion 186A or 186B/212U) of the semiconductor body extends between the well regions and is more lightly doped than each well region. The configuration of the well regions cause the maximum electric field in the IGFET's portion of the semiconductor body to occur well below the upper semiconductor surface, typically at or close to where the well regions are closest to each other. The IGFET's operating characteristics are stable with operational time.