半导体三极管在鲍和工作时，其等效电路可以用一极管及一个由集电极基极构成的二级管联成的电路表示出来，其中三极管在有源区工作，而二极管在正向温压下工作。这样的等效电路具有比较明显的物理意义。利用这个电路来求漂移管在一个共基电路中冲工作下的储存时间。解出非平衡少数流子的连惯性方程。求出二极管p-n结附近非平衡少数流于密度的稳定分量及态分量，从而得到决定储存时间的方程。计算结果表明，储存时间与基极区域集电区塸中非平衡流子的寿命及表面复合速度有关。减少寿命及增加表面复合速度就可以储存时间。

A theory of the switching respinse of the CBMOST (OR COOLMOST, or Super Junction device) is proposed based on the physical nd geo-metracal parameters inherent in the voltage sustaining structure. It is proven that the salient feature of such a device is that the storage time in turn-off process is a little longe than the conventional power Most due to its heavier doping. Explanation for the fast turn-on Process DESPITE OF Having an oppositely doped region inside the voltage sustaining layer is also given. It is also shown that if p-(or n-) regions in the CB-sturcture are not directly contacted to the n+(or p+) drain region. Then device is a normally-on one. Measures are proposed for the real device to be not normally-on.

The effect of the reduction of the peak fild at the deges of reverse-biased p-n junctions by the resistive field pcale (RFP) and varation lateral doping (VLD) is explained with the surface charges induced by their structures. Analytical solutions of the field profile under the RFP and under the CLD were found. From which the optimujm doping profile of the VLD can also be found. The relations between the breakdown voltage and surface depletion width for these two structures are proposed. The realization of the optimum YLD by an approach using multiple multiple zones of the JTE IS to be satisfactory.

The novel structure for surface voltage sustaining region makes power (or high-voltage) devices capable to implement on conventional CMOS or BiCMOS ICs without demanding additional process. The electrical performances of this king of power devices are much better than made by BCD techniques. Different kind of devices using for both low-side and high-side can be made.

The epitaxial layer resistance of a Mosfet can be slightly reduced by using an oprimum doping protile. Which exhibits a mini-mum in the upper half of the layer when the layer thickness is large compared to the cell-to-cell spacing. A gradual transition from the nepitaxial layer to the n+ subsuase is desirable. When conent spreading is significant. The resistance may rise ad V52 rather than Vb25.