Silicon epitaxial film growth on silicon substrate exposed to UV-excited NF3/H-2 gas for native oxide removal

In situ UV-excited NF3/H-2 gas phase cleaning for native oxide removal and Si epitaxial him growth experiments were carried out in a load-locked react or equipped with a UV lamp and PEN heater. The effect of composition of NF3 /H-2 and UV exposure on the etching characteristics of native oxide and the rmal oxide has been studied. Main etching species were identified as F, NFx and HF. Hydrogen added to NF3 gas alleviates silicon surface pitting to re sult in the very smooth surface. RMS surface roughness was as low as 0.5 An gstrom at the ratio of H-2/NF3 of 3. Analysis of silicon eptaxial film show ed the effectiveness of NF3/H-2 gas phase cleaning as the pretreatment proc ess prior to silicon eptaxial him growth. (C) 1999 Published by Elsevier Sc ience B.V. All rights reserved.