MOS transistor and method for manufacturing MOS transistor

摘要

A novel MOS transistor, which includes a source region, a drain region, a channel region, an isolation region, a drift region, a gate dielectric layer, a gate electrode and a field plate, is provided. The gate electrode has a first portion and a second portion. The first portion of a first conductivity type is located over the channel region and has a width equal to or greater than a distance of the gate electrode overlapped with the channel region. The second portion is un-doped and located over the isolation region. Accordingly, the MOS transistor allows higher process freedom saves production cost, as well as improves reliability.

主权项

1. A MOS transistor in a semiconductor substrate, the MOS transistor comprising:
a source region of a first conductivity type and a drain region of the first conductivity type in the semiconductor substrate; a channel region of a second conductivity type opposite to the first conductivity type in the semiconductor substrate between the source region and the drain region; an isolation region adjacent to the drain region; a drift region of the first conductivity type laterally adjacent to the channel region and beneath the isolation region and the drain region; a gate dielectric layer over the channel region and extending over the drift region; a gate electrode over the gate dielectric layer having a first portion and a second portion, wherein the first portion of the first conductivity type has a uniform or substantially uniform dopant concentration and is over the channel region and further extends over a portion of the drift region and a portion of the isolation region, the second portion is un-doped and over the isolation region, an interface between the first portion and the second portion is directly overlying the isolation region, and the first portion has a width less than a width of the second portion; and a field plate contacting an upper surface of the gate electrode, wherein the field plate comprises polycide.