A STUDY ON REACTION MECHANISM CONTROL UNDER LIGHT IRRADIATION IN ULTRACLEAN CLEANING OR HEATING PROCESSES OF SILICON SURFACES

点击翻译按钮获取中文摘要

Ultrathin silicon dioxide films have been formed on silicon wafers in ultrapure oxygen gas by the heating with infrared light irradiation, and tunneling current through the ultrathin silicon dioxide films or the dielectric breakdown voltage has been demonstrated to depend on the silicon wafer rinsing time with ultrapure water under megasonic irradiation before thermal oxidation. Ultrapure water rinsing with megasonic irradiation for 10 min is optimal to form ultrathin silicon dioxide films with high dielectric performances. The dielectric characteristics of ultrathin silicon dioxide films are sensitive to the microroughness of the silicon wafer surface determined by the rising process. The silicon wafer on which the ultrathin silicon dioxide film is formed by thermal oxidation has been exposed to air, and organic species adsorbed on the silicon dioxide surface have been identified. The organic species removed by ozonized ultrapure water rinsing of the silicon wafer or the organic species which are not efficiently removed have been determined. It has been found that the etching rate becomes low and the etched surface becomes flat by the irradiation of the ultraviolet light including the light with the energy higher than that of the silicon bandgap on a silicon wafer during wet etching. A silicon dioxide film has been found to be formed by the irradiation of the semiconductor laser light with the energy higher than that of the silicon bandgap on a hydrogen-terminated silicon wafer dipped in ultrapure water. This suggests that the silicon surface can be patterned by etching the silicon dioxide film.