Deep level transient spectroscopy study of the damage induced in n-type silicon by a gate oxide etching in a CHF3/Ar plasma

Deep level transient spectroscopy was used to detect the presence of deep levels correlated to the defects induced in the Si substrate by a CHF3 /Ar dry etch of a 550 Å gate oxide as a function of the rf power. Several energy levels were observed; some of them were due to the processing before the dry etching. Three traps produced by the dry etching, with Arrhenius plot activation energies, respectively, Ena15350 meV, Ena25220 meV, and Ena35100 meV, and capture cross sections around 10220 cm2 were detected. The correlation with the surface recombination velocity variations and the F and C diffusion in the Si substrate was investigated.