Feasibility of Using Finite Elements in Analysis of Second Breakdown in Semiconductor Devices.

摘要

Mathematical characterization of the operation of a transistor during second breakdown has proved to be extremely complicated,because not only is it impossible to make the usual one-dimensional approximations of ordinary transistor analysis,but there is also a strong spatial dependence on temperature (the material may even change state) and the extremes of operating conditions prevail. Moreover, a highly time-dependent solution is required. As a means of demonstrating the utility of the method of finite elements in analyzing semiconductor performance, a numerical method is developed for predicting two-dimensional flow in a pn junction before,during,and after second breakdown and including damage. The model accounts for spatial and temporal dependence of voltage,temperature,hole density,and electron density. The ease with which oddly shaped boundaries,material inhomogeneities,and nonlinear variation of coefficients is handled by the method of finite elements is discussed. (Author)