High power MOSFET and integrated control circuit therefor for high-side switch application

Claim 1

A power integrated circuit integrally including a power MOSFET and an electrically-isolated control circuit for controlling the switching state of said power MOSFET; said power MOSFET being for placement on the high potential side of a load; said control circuit being formed in the power integrated circuit atop a substrate of monocrystalline semiconductor material; said power MOSFET also being formed atop said substrate, being electrically isolated from said control circuit, and including a first layer of a first conductivity type formed atop said substrate, defining a reduced surface field first region, and having top and bottom surfaces; a surface-adjoining body region of a second conductivity type formed in said first layer and comprising first and second laterally-spaced segments; a surface-adjoining source region of said first conductivity type formed in said first layer and having first and second segments respectively within said first and second body region segments; said first and second source region segments spaced from confronting edges of said first and second body region segments respectively and defining respective first and second surface channel segments at said top surface of said first layer; the laterally-outwardly spaced portions of said first and second body region segments respectively adjoining said first and second source region segments and having a substantially greater conductivity than the adjacent laterally-inwardly spaced portions of said first and second body region segments for suppressing parasitic bipolar transistor turn-on; a gate oxide and gate electrode formed atop said surface channel; a drain region of said first conductivity type formed in said first layer and comprising first and second laterally-spaced segments spaced laterally outwardly of said first and second body region segments; a second region of said second conductivity type formed in said first layer and comprising a first segment interposed between said first body region segment and said first drain region segment and defining a reduced surface field region segment and a second segment interposed between said second body region segment and said second drain region segment and defining a reduced surface field region segment, whereby current flow from said surface channel has a vertical component from said surface to a depth greater than the depth of said second region, and first and second lateral components respectively beneath said first and second segments of said second region; said first region having a total charge approximately equal to the charge which will be depleted from both the top and bottom of said first region when said device is off; said second region having a total charge of approximately 1×10 12 ions/cm 2 .