Low Temperature Growth of Silicon Dioxide Thin Films by UV Photo-oxidation

Abstract

AbstractThe low-temperature growth of thin SiO2 layers for gate insulators in very large-scale integrated (VLSI) circuits is becoming an urgent topic of silicon technology. In contrast, to conventional thermal oxidization processes (T>900°C), ultraviolet (UV) photo-oxidation of silicon technology is a promising approach for low-temperature growth of silicon dioxide thin films. We have grown silicon dioxide thin films at low temperature (T<500 °C) using an excimer lamp with various wavelengths and evaluated the quality of thin SiO2 layers as well as the SiO2–Si interface. We found that the SiO2 layers (t<5 nm) grown by UV photo-oxidation show significant differences in physical properties, such as density profile, from those of thermal oxidization, i.e., the higher average density 2.23 g/cm3 and more constant distribution, making the SiO2–Si interface region, so-called “transition layer” less eminent. Superior characteristics of ultra-thin SiO2 layer grown by UV photo-oxidation are demonstrated.