Thermoelectronic-wave coupling in laser photothermal theory of semiconductors at elevated temperatures

Abstract

A quantitative analysis of linear temperature-dependent coupled thermoelectronic diffusion waves in the generation of the laser-induced IR photothermal radiometric signal from a photoexcited, plasma-wave-dominated, semi-infinite semiconductor Si wafer is presented. The strong coupling between the (usually assumed decoupled) carrier and thermal wave transport equations is accounted for explicitly and the range of violation of the Vasil’ev-Sandomirskii condition is studied. Thermoelectronic coupling is found to degrade the sensitivity of the plasma-originating IR radiometric signal in high-quality process Si substrates at elevated background temperatures and high modulation frequencies, with the exception of highly degenerate plasmas. © 1997 Society of Photo-Optical Instrumentation Engineers.