| 摘要 |
<p>A drifted drain MOS transistor incorporates a P-type channel (15) between P type regions (14,16) located between the source and the drain regions. The P- channel (15) provides a conduction path from the region below the gate (22) to the P drain region. When a large reverse bias is present at the P-N junction, the P-channel region (15) depletes producing a P-channel MOS transistor with high breakdown voltage and high lateral PNP current gain when operated with the drain as its emitter. When the PMOS transistor is fabricated in an N- well (28) surrounded by P- type material (30), the vertical PNP current gain of the bipolar transistor formed with the drain on the collector is low when compared to the lateral PNP current gain.</p> |
