| 摘要 |
A high-voltage LDMOSFET(laterally diffused metal-oxide-semiconductor field-effect-transistor) is provided to avoid a current reverse phenomenon by forming a count split P-type drift region or a count P-type drift region in a channel region that has an opposite conductivity type to that of an N-type drift region in which a drain region is formed. A well(22) of first conductivity type is formed in a semiconductor substrate(21). A gate oxide layer(24) and a gate electrode(25) are stacked on the well of first conductivity type. A drift region(27) of second conductivity type is formed in the well of first conductivity type at both lateral surfaces of the gate electrode. A drain region(28b) is formed at one side of the drift region of second conductivity type. A source region(28a) is formed at the other side of the drift region of second conductivity type. A count drift region(26a) has an opposite conductivity type to that of the drift region of second conductivity type in which the drain region is formed, formed in the channel region under the gate electrode and adjoining the drift region of second conductivity type in which at least the drain region is formed. The outer part of the drift region of second conductivity type is surrounded by a drift region(26b) of first conductivity type. A field oxide layer(23a,23b) is locally formed in the semiconductor substrate between the drift region of second conductivity type and the corner of the gate electrode.
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