Atomic Layer Deposition (ALD) of ZrO2in Ultrahigh Vacuum (UHV)

摘要

The atomic layer deposition (ALD) of ZrO2 was conducted in ultrahigh vacuum (UHV) conditions. The surface was exposed to ZrCl4 and H2O in sequence and the surface species produced after each step were identified in situ with X-ray photoelectron spectroscopy (XPS). ZrCl4 is molecularly adsorbed at 140 K on the SiO2/ Si(l 11) surface covered with OH groups. When the surface is heated to 300 K, ZrCl4 loses two Cl atoms to produce ZrCl2 species. Remaining Cl atoms of ZrCl2 species can be completely removed by exposing the surface to H2O at 300 K followed by heating to 600 K. The layer-by-layer deposition of ZrO2 was successfully accomplished by repeated cycles of ZrCl4 dosing and H2O treatment.