MEASUREMENT OF THE THERMAL-CONDUCTIVITY OF SI AND GAAS WAFERS USING THE PHOTOTHERMAL DISPLACEMENT TECHNIQUE

Thermal conductivity and thermal diffusivity of Si and GaAs wafers wer e measured using the photothermal displacement technique, and the temp erature dependence of these two quantities was investigated. Thermal d iffusivity was obtained from the phase difference between the healing source and the signal, and thermal conductivity was determined From th e maximum value of the signal amplitude in the temperature range 80 to 300 K. It was verified that an increase in doping concentration gives rise to a decrease in thermal conductivity at low temperatures. The e xperimental results obtained on samples with different types and dopin g concentrations are consistent with those expected from theoretical c onsiderations.