Passivation of Ge ( 100 ) ∕ GeO2 ∕ high-κ Gate Stacks Using Thermal Oxide Treatments

The physical and electrical properties of Ge/GeO 2 /high-κ gate stacks, where the GeO 2 interlayer is thermally grown in molecular oxygen, are investigated. The high-K layer (ZrO 2 , HfO 2 , or Al 2 O 3 ) is deposited in situ on the GeO 2 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 HfO 2 -based gate stacks, as compared to Al 2 O 3 gate stacks, which is possibly related to the more pronounced intermixing observed between the HfO 2 and GeO 2 .

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