Wet chemical cleaning effect on the formation of ultrathin interfacial layer between Germanium (Ge) and high-k dielectric

This paper investigates and discusses the effect of wet chemical cleaning; Hydrochloric Acid (HCl) and Hydrofluoric Acid (HF) to the growth of interfacial layer between high-k material (Al2O3) and Ge (100) surface. Characterization and morphology techniques using Field Emission Scanning Electron Microscope (FESEM) was carried out to determine the thickness of interfacial layer between Al₂O₃ and Ge (100) surface. Results of this study showed that an HF treatment gives a rougher surface of Al₂O₃ than HCl treatment. Both wet chemical cleaning resulted with step and terrace trend of Al₂O₃ and interfacial layer. This may be due to initial Ge surface just after HF cleaning is rougher than the initial Ge surface after HCl cleaning.