US PATENT SUBCLASS 257 / 492
.~.~ With electric field controlling semiconductor layer having a low enough doping level in relationship to its thickness to be fully depleted prior to avalanche breakdown (e.g., RESURF devices)

Current as of: June, 1999
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257 /   HD   ACTIVE SOLID-STATE DEVICES (E.G., TRANSISTORS, SOLID-STATE DIODES)

487  DF  WITH MEANS TO INCREASE BREAKDOWN VOLTAGE THRESHOLD {6}
491  DF  .~ In integrated circuit {1}
492.~.~ With electric field controlling semiconductor layer having a low enough doping level in relationship to its thickness to be fully depleted prior to avalanche breakdown (e.g., RESURF devices)

DEFINITION

Classification: 257/492

With electric field controlling semiconductor layer having a low enough doping level in relationship to its thickness to be fully depleted prior to avalanche breakdown (e.g., RESURF devices):

(under subclass 491) Subject matter wherein the means to increase breakdown voltage of the device includes a layer of semiconductor material having a sufficiently low doping concentration that it may be fully depleted by the depletion region of a reverse biased junction of the active device prior to avalanche breakdown of the active device, so that upon depletion of the layer of semiconductor material, the effective width of the depletion layer of the reverse biased junction of the active device is greatly expanded, thus resulting in smaller increases in electric field intensity with further increases of reverse voltage.

(1) Note. Devices provided with such a layer are sometimes called "RESURF" (Reduced SURFace Field) devices.

(2) Note. In silicon, to be fully depleted without avalanche breakdown, a layer must typically have an

integrated doping density (the line integral of doping density along a path through the thickness of the layer) of less than 2x10[supscrpt]12[end supscrpt] dopant atoms/cm[supscrpt]2[end supscrpt]. The critical integrated doping density varies depending on the properties of the particular semiconductor material.