The surface field and the potential distribution of an abrupt planar junction with the FFLR'S is derved derved by making use of cylindric solution of Polsson's equation and Laplace's equation, The design guidelines of the FFLR's system are given, It is shown in this paper that a positive surface charge increases the maximum electric field and the voltage between the rings in p+-n planar junction.

The electric field profile in the drift region of power MOSFET's with lateral structures and deep junctions been found analytically. From the analysis, the best uniform surface doping den-sity and the depth of the drift region in offset-gate power Mosfet's that introduces the minimum seies resistance and sustains a given junction breakdown voltage is derived. Design guidelines for such MOSFET's are proposed. The comparison with computer simulation results bas shown that it is reasonable for some practical structures.

本文探讨了在一个方向是不均匀的媒质中应用镜像法求解恒定电场问题的可能性。得到一个描述镜像的二变量二防线性分方程。对于均匀媒质的情形。方程是常系数的。精合边界条件可以推演出计算电场或电位分布的所有镜象。对于不均匀媒质的情形。方程不是常系数的。这时虽然原则上可以用镜象法。但所需求解的议程和白电流连惯性（导体的电流场问题中）或电位通量连惯性（在电介质的静电电场问题中）缎带出的方程差不多同样复杂面难于计算。

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.