Atomic force microscopy observation of layer-by-layer growth of ultrathin silicon dioxide by ozone gas at room temperature

Atomic structures on active oxidized silicon films by an ozone gas at room temperature are investigated by an atomic force microscopy. A step-terrace structure similar to that on a clean Si (001) prepared by a silicon homoepitaxy is preserved on the ozone oxidized surface. These atomically regulated structures are also discernible on the SiO2/Si interface when a 1.0-nm-thick SiO2 film oxidized by an atmospheric ozone is removed by a diluted HF etching. It is revealed that the homogeneous lateral oxide growth, i.e., layer-by-layer growth, proceeds at room temperature by an active oxidant such as ozone.