Effect of high-pressure H₂O treatment on elimination of interfacial GeO_X layer between ZrO₂ and Ge stack

This investigation demonstrates the effect of high-pressure H₂O treatment on the elimination of the interfacial germanium suboxide (GeO _X) layer between ZrO₂ and Ge. The formation of GeO _X interlayer increases the gate-leakage current and worsen the controllability of the gate during deposition or thermal cycles. X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy reveal that high-pressure H₂O treatment eliminates the interfacial GeO_X layer. The physical mechanism involves the oxidation of non-oxidized Zr with H₂O and the reduction of GeO_X by H₂. Treatment with H₂O reduces the gate-leakage current of a ZrO₂/Ge capacitor by a factor of 1000.