We try to obtain the common-base current gain a of the parasitic PNP transistor from the eloping profile of the collector region including the effect of buried-layer.
本文从包括埋层影响的集区杂质分布出发，求出了寄生PNP晶体管的共基极电流放大系数。
2
The model considers the drift velocity saturation of carriers and influence of parasitic bipolar transistor. As a result, electric field profile of n drift in LDMOS at on state is obtained.