CHARACTERIZATION OF DRY ETCH-INDUCED DAMAGE IN SEMICONDUCTOR-MATERIALS USING A NONCONTACT PHOTOTHERMAL RADIOMETRIC PROBE

Defects induced in n-type silicon (Si) and gallium arsenide (GaAs) substrates by argon ion bombardment in reactive ion etch and reactive ion beam etch reactors, respectively, have been studied for the first time using photothermal radiometry (PTR). A significant shift in measured PTR signal amplitude has been observed as a function of isochronal bias voltage variation (0-600 V) etching studies. The experimental results have been interpreted using a model for the photothermal radiometric response from a layered semiconductor material. The detection of a threshold effect for dry etch induced process defects in GaAs has been correlated with Raman spectroscopy measurements. Both theory and experimental results indicate that PTR has the requisite surface sensitivity to variations in lattice quality to be a suitable technique for rapid and noncontact process control monitoring of dry-etch-induced damage.