STUDIES OF ELECTRICAL AND CHEMICAL-PROPERTIES OF SIO2 SI AFTER RAPID THERMAL NITRIDATION USING SURFACE-CHARGE SPECTROSCOPY AND X-RAY PHOTOELECTRON-SPECTROSCOPY/

Development of high quality ultrathin dielectric films of thickness le ss than 100 Angstrom has become an important research subject due to t he scaling down of semiconductor devices. In the present study, sample s with 20-100 Angstrom SiO2 on silicon were prepared by dry oxidation, and subsequently subjected to rapid thermal nitridation (RTN) using N H3 in the temperature range of 800-1200 degrees C. X-ray photoelectron spectroscopy and surface charge spectroscopy were applied to study th e nitrogen distribution in the dielectric layers, the changes in the i nterface state density, D-it, and the dielectric breakdown field stren gth due to the nitrogen incorporation. It was found that nitrogen was mainly incorporated to the dielectric at the dielectric/Si interface w ithout any consumption of silicon in the substrate during RTN. In the study of the electrical properties, we found that RTN led to a slight decrease in D-it and an increase in the breakdown field strength. (C) 1997 American Society.