Electric field profiling by current transients in silicon diodes

A novel method, suitable to evaluate the electric field distribution in the space charge region of silicon diodes directly from the measurement of their pulse current response, is proposed. A Transient Current Technique experimental setup, based on a nano-second UV laser, is used for this purpose. It is shown that the problem of solving the basic equations, connecting the current response to the electric field distribution, can be expressed by a linear integral equation. An iterative mathematical procedure is used to obtain the solution, and a spatial resolution of about 10 mm, comparable to the accuracy obtainable from other commonly used techniques, is deduced from the numerical tests. A preliminary analysis of measured data has also been carried out; the results are encouraging, but they point out that a refinement of the transport model is needed to reach a satisfactorily practical applicability.