<title>Physical and electrical properties of thin dielectrics prepared by photoassisted growth in an NO environment</title>

Abstract

The necessity to decrease silicon wafer-processing temperatures substantially has stimulated research into new and innovative techniques for the formation of thin dielectric films. A photo-decomposition technique using nitric oxide (NO) is one such promising method. Thermally NO-grown and NO-annealed dielectric film shave already shown very encouraging physical and electrical properties. The purpose of this study is to investigate the effect of UV irradiation on the growth kinetics and on the electrical and physical characteristics of these thin dielectrics and to simulate the decomposition of NO molecules that occurs thermally above 1000 degrees C. Methods using UV and vacuum UV light generated from low-pressure mercury or deuterium lamps to stimulate the growth of ultrathin dielectric films are described. Thin dielectrics were prepared by irradiating a UV beam on the heated silicon substrate covered by a thin layer of nitric oxide gas at different temperatures for various lengths of time. The films grown under the low- pressure mercury lamp displayed a much faster growth rate than under the deuterium lamp. The electrical characteristics of the films grown using a deuterium lamp show encouraging results compared to the low-pressure mercury. Compositions of the various dielectrics formed under the two UV sources were studied using x-ray photoelectron spectroscopy. MIS devices were fabricated using these films as gate insulators and were electrically characterized. Electrical and physical characterization revealed good film qualities, rendering this new UV-NO dielectric growth technique promising for low temperature semiconductor processing.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.