Recovery of silicon surface after reactive ion etching of SiO2 using CHF3/C2F6

The effects of SF6 or NF3 gas plasma and subsequent rapid thermal anneal (RTA) treatment for the recovery of modified silicon surfaces after reactive ion etching (RIE) with CHF3/C2F6 plasma were investigated using X-ray photoelectron spectroscopy and secondary ion mass spectrometry. NF3 or SF6 plasma treatment effectively removed the residue layer and impurities in the silicon substrate were removed by the subsequent RTA treatment at 700 degrees C. The effects of NF3 or SF6 plasma and the additional RTA treatment in recovering the reactive ion etched silicon surface were also studied by measuring the leakage current densities and the barrier heights of post-treated PtSi/n-type Si Schottky barrier diodes. The minimum leakage current and the maximum barrier height were obtained after NF3 plasma and subsequent RTA treatment, which constitute the most probable recovery process for silicon surfaces contaminated by RIE.