Title :
Microwave-detected photoconductance decay
Author :
Basore, Paul ; Hansen, Barry
Author_Institution :
Sandia Nat. Lab., Albquerque, NM, USA
Abstract :
Microwave-detected photoconductance decay provides a contactless measurement of the recombination lifetime of free carriers in semiconductors following a pulse of optical excitation. Several complications in interpreting the results obtained by this method have prevented its widespread acceptance. Detailed models are proposed and verified experimentally using a commercially available apparatus. The model adequately predicts the behavior of the microwave reflectance as a function of wafer conductivity and system configuration. A light-biased variation of the technique which makes it possible to characterize lifetimes as a function of excess carrier density is described. This capability makes it possible to measure the emitter saturation current density for diffusion in high-resistivity wafers, a valuable process control tool
Keywords :
carrier lifetime; electrical conductivity measurement; electron-hole recombination; microwave reflectometry; minority carriers; photoconductivity; semiconductors; contactless measurement; emitter saturation current density; free carriers; high-resistivity wafers; microwave detected photoconductance decay; microwave reflectance; optical excitation; recombination lifetime; semiconductors; wafer conductivity; Microwave measurements; Optical pulses; Optical saturation; Photoconducting devices; Photoconductivity; Predictive models; Pulse measurements; Radiative recombination; Reflectivity; Semiconductor device modeling;
Conference_Titel :
Photovoltaic Specialists Conference, 1990., Conference Record of the Twenty First IEEE
Conference_Location :
Kissimmee, FL
DOI :
10.1109/PVSC.1990.111651
