Computational aspects of laser radiometric multiparameter fit for carrier transport property measurements in Si wafers

A laser infrared photothermal radiometric (PTR) multiparameter-fit methodol ogy has been developed to obtain unique measurements of the thermal and ele ctronic parameters of industrial-type Si wafers. The influence of recombina tion lifetime, front, and back surface recombination velocities, carrier el ectronic diffusion coefficient, thermal diffusivity (alpha), as well as of the total plasma and thermal contributions to the PTR signal as a function of frequency is examined computationally and experimentally in this paper. Silicon wafers with low and high resistivity were studied with the proposed methodology. A strong correlation between nominal resistivity, front surfa ce recombination velocity, and recombination lifetime was found: higher res istivity wafers are likely to have lower surface recombination velocity and longer lifetimes. The first PTR lifetime scanned image of subsurface elect ronic defects has also been produced. (C) 2000 The Electrochemical Society. S0013-4651(99)05-082-X. All rights reserved.