A new etching method for single-crystal Al 2O 3 film on Si using Si ion implantation

Abstract

A new etching method for a single-crystalline Al 2O 3 (100) film grown on Si (100) by chemical-vapour deposition (CVD) and a sapphire wafer is proposed for the first time using Si ion implantation and HF chemical etchant to develop potential applications of the silicon on insulator (SOI) structure. Line and space patterns of resist are transferred to sharp Al 2O 3 and Si patterns. The etch rate is 100 Å min −1 under implanted conditions of 80 kV and 3 × 10 15 cm −2 for 0.1 μm thick Al 2O 3. The implanted Al 2O 3 surfaces are investigated by secondary ion mass spectroscopy (SIMS) and X-ray photoelectron spectroscopy (XPS). The change of the surface structure from Al 2O 3 to Al 2O 3 · SiO 2 (aluminosilicate) is the dominant reason for this etching rather than a surface-damage effect caused by implantation.