Power semiconductor devices have a plurality of arcuate-shaped source regions arranged in a row along a serpentine-shaped insulated gate electrode and at least one bypass region for collectively inhibiting parasitic thyristor latch-up. These power semiconductor devices include a semiconductor...http://www.google.com.tw/patents/US5753942?utm_source=gb-gplus-share專利 US5753942 - Power semiconductor devices having arcuate-shaped source regions for inhibiting parasitic thyristor latch-up 
