MODELING OF THE PHOTOTHERMAL RADIOMETRIC RESPONSE OF A LAYERED DIELECTRIC-ON-SEMICONDUCTOR STRUCTURE

On-line material fabrication process control requires the development of rapid, non-destructive and non-contact characterization technology. One promising approach is based on the use of photothermal radiometry (PTR). Recently this technique has been applied to the characterization of semiconductor materials. However, accurate interpretation of the detected signal requires the use of models which describe the physical mechanisms responsible for the radiometric response. In this paper we present an analysis of the PTR response from a layered structure comprising a thin film dielectric on a semiconductor. The equations employed take into account the optical absorption coefficient of the materials at specific excitation and detection wavelenghts. In addition the effect of experimental factors such as the bandwidth of the detector have been included. The relative contributions of the contrast mechanisms in the PTR response are examined and regimes are considered where the observed response is predominantly sensitive to the electronic properties of the semiconductor. © 1990.