The kinetics of Si surface etching with gas-phase O2 was examined using scanning tunneling microscopy (STM), which was intended for the application of gas-phase etching by O2 for Si surface flattening. High-temperature STM observation showed the recession of the step edges with the O2 flux of 5 × 10-8 Torr on Si(111) at an elevated temperature of ∼800°C in real time. The high-resolution image clearly showed that the terrace was disordered during the exposure to O2 gas. The recession of step edges is considered to be the result of the detachment of Si atoms from the step edges to fill the defects created by the desorption of SiO.
- Elevated temperature
- Scanning tunneling microscopy (STM)
- Step motion
- Surface etching