Photothermal reflectance investigation of processed silicon. II. Signal generation and lattice temperature dependence in ion-implanted and amorphous thin layers

Abstract

Photothermal reflectance investigations as a function of temperature of various forms of silicon (crystalline, ion‐implanted, amorphous) are reported largely in the thermal wave regime (low‐modulation frequencies and large laser beam spot sizes). The observed results have been explained by a thermal wave model that has been extended to include the effect of lattice temperature. The influence of substrate on the observed signal has been examined in light of the temperature and frequency dependence of the thermal diffusion length. The possible application of the technique to depth‐profiling studies, and to the investigation of ion‐implanted semiconductors, is discussed.