Electrochemical Evaluation of the Electronic and Transport Properties of Silicon - Phase I

摘要

Measurement of the minority carrier diffusion length and the major carrier doping density of p- and n-type samples through the use of a liquid-semiconductor junction in an electrochemical cell has been demonstrated. Techniques employed make use of the Schottky-type barrier which forms between semiconductors and certain redox electrolytes. The electrical and optical properties of such a barrier can be used to determine doping densities, as well as carrier lengths, lifetimes, and mobilities. The CH3OH, I-1/I2 redox electrolyte system was chosen because of its stability with respect to silicon passivation and its simplicity of preparation. Both the doping density and diffusion length can be measured in the same two-electrode cell with this redox electrolyte for either n- or p-type silicon samples for a large range of doping densities. Surface photovoltage and pulsed spacecharge capacitance were employed because of their respective insensitivity to surface recombination and surface state effects. The electrochemical techniques used in this study provide rapid, reliable, and nondestructive measurements of semiconductor parameters which are essential in the evaluation of silicon used in the fabrication of electronic devices.