Electrical Properties and Interfacial Issues of HfO2/Ge MIS Capacitors Characterized by the Thickness of La2O3 Interlayer.

Effects of the La2O3 passivation layer thickness on the interfacial properties of high-k/Ge interface are investigated systematically. In a very thin range (0~15 cycles), the increase of La2O3 passivation layer deposition cycles improves the surface smoothness of HfO2/Ge structures. The capacitance-voltage (C-V) characteristics show that the thickness of La2O3 passivation layer can affect the shift of flat band voltage (VFB), hysteretic behaviors, and the shapes of the dual-swept C-V curves. Moreover, significant improvements in the gate leakage current and breakdown characteristics are also achieved with the increase of La2O3 interlayer thickness.