| 摘要 |
Adverse tradeoff between BVDSS and Rdson in LDMOS devices employing a drift space (52, 152) adjacent the drain (56, 156), is avoided by providing a lightly doped region (511, 1511) of a first conductivity type (CT) separating the first CT drift space (52, 152) from an opposite CT WELL region (53, 153) in which the first CT source (57, 157) is located, and a further region (60, 160) of the opposite CT (e.g., formed by an angled implant) extending through part of the WELL region (53, 153) under an edge (591, 1591) of the gate (59, 159) located near a boundary (531, 1531) of the WELL region (53, 153) into the lightly doped region (511, 1511), and a shallow still further region (66, 166) of the first CT Ohmically coupled to the source (57, 157) and ending near the gate edge (591, 159) whereby the effective channel length (61, 161) in the further region (60, 160) is reduced to near zero. Substantial improvement in BVDSS and/or Rdson can be obtained without degrading the other or significant adverse affect on other device properties.
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