Determination of Electrophysical Parameters of a Semiconductor from Measurements of the Microwave Spectrum of Coaxial Probe Impedance

We propose a method for determining electrophysical characteristics (free charge carrier concentration, mobility, and conductivity) of semiconductors from the results of measurements of the microwave spectrum of the impedance of a coaxial probe as a function of applied constant voltage U. The sought parameters have been determined by solving the corresponding inverse problem using the theory of a near-field antenna that was developed earlier. We have developed a computer program that seeks the solution by minimization of the multiparametric residual function in accordance with the Nelder-Mead algorithm. The precision of the method has been analyzed from the results of simulation in which the impedance was calculated preliminarily considering resultant concentration profile n(x, U) of the depleted layer in the vicinity of the metal-semiconductor contact. The possibility of diagnostics with a micrometer lateral resolution has been demonstrated.