Scully, Scott, Murphy & Presser, P.C.
Bidirectional electrostatic discharge protection structure for high voltage applications
Semiconductor structures providing protection against electrostatic events of both polarities are provided. A pair of p-n junctions is provided underneath a shallow trench isolation portion between a first-conductivity-type well and each of a signal-side second-conductivity-type well and an electrical-ground-side second-conductivity-type well in a semiconductor substrate. A second-conductivity-type doped region and a first-conductivity-type doped region are formed above each second-conductivity-type well such that a portion of the second-conductivity-type well resistively separates the second-conductivity-type doped region and the first-conductivity-type doped region within the semiconductor substrate. Each of the second-conductivity-type doped regions is wired either to a signal node or electrical ground. One of the two npn transistors and one of the two p-n diodes, each inherently present in the semiconductor structure, turn on to provide protection against electrical discharge events involving either type of excessive electrical charges.
International Business Machines Corporation
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additional additional inventional inventional
Junjun Robert Michel J.
Li Gauthier Abou-Khalil