Highly Reliable Thin Silicon Dioxide Layers Grown on Heavily Phosphorus Doped Poly‐Si by Rapid Thermal Oxidation

Abstract

Highly reliable thin silicon dioxide layers are grown by rapid thermal oxidation on heavily phosphorus doped poly‐Si layers. Oxide layers as thin as 5 nm are grown with high controllability by choosing appropriate oxidation temperature and time. Breakdown field is improved by about 40%, as compared with that of oxides grown by conventional furnace oxidation. Time‐dependent dielectric breakdown characteristics of the oxide layers under high electric field are also improved by one order of magnitude. The major reason for the high reliability is attributed to the improvement of the interface morphology of poly‐Si and silicon dioxide. Rapid thermal oxidation should be the key technology for the sub‐μm ULSI DRAMs in stacked as well as in trench capacitor cell fabrication.