| 摘要 |
Methods and apparatus are provided for a MOSFET ( 50, 99, 199 ) exhibiting increased source-drain breakdown voltage (BVdss). Source (S) ( 70 ) and drain (D) ( 76 ) are spaced apart by a channel ( 90 ) underlying a gate ( 84 ) and one or more carrier drift spaces ( 92, 92 ') serially located between the channel ( 90 ) and the source ( 70, 70 ') or drain ( 76, 76 '). A buried region ( 96, 96 ') of the same conductivity type as the drift space ( 92, 92 ') and the source ( 70, 70 ') or drain ( 76, 76 ') is provided below the drift space ( 92, 92 '), separated therefrom in depth by a narrow gap ( 94, 94 ') and ohmically coupled to the source ( 70, 70 ') or drain ( 76, 76 '). Current flow ( 110 ) through the drift space produces a potential difference (Vt) across this gap ( 94, 94 '). As the S-D voltage (Vo) and current ( 109 , Io) increase, this difference (Vt) induces high field conduction between the drift space ( 92, 92 ') and the buried region ( 96, 96 ') and diverts part ( 112 , It) of the S-D current ( 109 , Io) through the buried region ( 96, 96 ') and away from the near surface portions of the drift space ( 92, 92 ') where breakdown generally occurs. Thus, BVdss is increased.
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