| 摘要 |
A method for fabricating high voltage semiconductor devices having a gradient doping of a drift region which comprises N-well 1 and N-well 2 with two different doping densities. This method results in the lift in device's current drive capability and as well as its breakdown voltage. The method further comprises forming a buried spacer oxide, serving as a point of exertion for the edges of the buried gate electrode. And finally, the extension in channel length and the placement of both the channel and drift regions change to vertical direction, all of those result in a greater reduction in the occupied chip area. These advantages attribute to the formation of a buried gate electrode by trench etching method.
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