Comparison of the interfacial and electrical properties of HfAlO films on Ge with S and GeO2 passivation.

We report the characteristics of HfAlO films deposited on S- and GeO₂-passivated Ge substrates at 150 °C by atomic layer deposition technique using Hf(NO₃)₄ and Al(CH₃)₃ as the precursors. The x-ray photoelectron spectroscopic analyses reveal that GeO₂ passivation is more effective to suppress GeO_x formation than S passivation. It is demonstrated that the capacitors with GeO₂ passivation exhibit better electrical properties with less hysteresis, improved interface quality, and reduced leakage current. These results indicate that using GeO₂ as an interfacial layer may be a promising approach for the realization of high quality Ge-based transistor devices. [ABSTRACT FROM AUTHOR]