NONCONTACTING PHOTOTHERMAL RADIOMETRY OF SIO2 SI MOS CAPACITOR STRUCTURES/

An infrared photothermal radiometric (PTR) method has been applied to the SiO2/Si interface noncontact diagnostics. Both photothermal freque ncy-domain (PTR-FD) and photothermal deep-level transient spectroscopy (PTR-DLTS) analyses have been performed on two full-size Si wafers co ntaining Al and poly-Si gated MOS structures. A new fitting procedure which uses both the PTR-FD amplitude and phase frequency responses is proposed allowing the measurements of the values of the carrier diffus ivity, lifetime and surface recombination velocity. A behavior consist ent with photoinjected carrier lifetime enhancement due to trap therma l filling at elevated temperatures has been observed on both wafers. T he activation energies measured by the two photothermal techniques are found to be close: 0.15-0.17 eV and 0.21 eV below the bottom of the c onduction band for Al-gated and poly-Si gated wafers, respectively. (C ) 1997 Elsevier Science Ltd.