Passivation of Ge(100)?GeO[sub 2]?high-? Gate Stacks Using Thermal Oxide Treatments

Abstract
The physical and electrical properties of Ge∕GeO2∕high-κGe∕GeO2∕high-κ gate stacks, where the GeO2GeO2 interlayer is thermally grown in molecular oxygen, are investigated. The high-κ layer ( ZrO2ZrO2 , HfO2HfO2 , or Al2O3Al2O3 ) is deposited in situ on the GeO2GeO2 interlayer by atomic layer deposition. Detailed analysis of the capacitance-voltage and conductance-frequency characteristics of these devices provides evidence for the efficient passivation of the Ge(100) surface by its thermal oxide layer. A larger flatband voltage hysteresis is observed in HfO2HfO2 -based gate stacks, as compared to Al2O3Al2O3 gate stacks, which is possibly related to the more pronounced intermixing observed between the HfO2HfO2 and GeO2GeO2 .