Theoretical and experimental aspects of three-dimensional infrared photothermal radiometry of semiconductors

A general theoretical model for the infrared photothermal radiometric (PTR) signal from a semiconductor wafer is developed for the case of three-dimensional sample geometry with finite thickness. Carrier diffusion and heat conduction along the radial direction of the sample as well as along the thickness coordinate are taken into account. The simulated results for the modulation frequency dependence of the PTR signal amplitude and phase are applied to experimental data from Si wafers. Good agreement between the theoretical and experimental curves is obtained and several electronic and thermophysical parameters are estimated. This indicates that the three-dimensional PTR measurement is useful to remotely characterize semiconductor wafers patterned for large scale integrated circuits. (C) 1999 American Institute of Physics. [S0021-8979(99)01310-9].