| 摘要 |
A MOSFET and IGBT are described that exhibit high breakdown voltage together with low on-resistance. This is achieved by providing an N type shunt that extends from the N+ drain (for power MOSFETs) or P+ emitter (for IGBTs), through the N- region to a short distance below the gate oxide. To manufacture such a shunt, an epi wafer with N-epitaxy is first provided on top of an N+ (for power MOSFET) or P+ (for IGBT) layer. Through a suitable mask (contact or freestanding) on the top surface, the wafer is then subjected to bombardment by protons or deuterons. Because of ion transmutation doping, a region of N type material forms wherever the surface is not masked. By controlling the energies of the ions, this region is caused to extend below the wafer's surface so as to just contact the N+ or P+ layer or even to go through it. To convert shunt material in the immediate vicinity of the gate oxide back to N-, either counter-doping or trenching followed by dielectric filling and CMP are used.
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