Novel ultra thin gate oxide growth technique by alternating current anodization

Ultra-thin gate oxides prepared by the novel anodic oxidation technique of using direct-current (DC), alternating-current (AC), and direct-current with ac oscillation (DAC) as anodization voltages are studied. After suitable high temperature anneal in N/sub 2/, these anodic oxides (ANO) show improved uniformity in electrical characteristics with respect to conventional rapid thermal oxides. Smaller leakage current and higher breakdown endurance are observed for these ANO oxides. Specially, DAC-ANO oxides present a further improved breakdown performance than the other oxides. Further, anodization is carried out with N-type Si (ANO-Si) replacing Pt as the cathode. ANO-Si oxides demonstrate even preferable reliability and superior electrical uniformity.