Interfacial layer reduction and high permittivity tetragonal ZrO2 on germanium reaching ultrathin 0.39 nm equivalent oxide thickness

The nearly free interfacial layer and the tetragonal phase ZrO2 with the high permittivity of 45 ± 3 on Ge (001) substrate lead to the equivalent oxide thickness as low as 0.39 nm and the low leakage current density of 2 × 10−3 A/cm−2. The ultrathin GeON layer formed by remote plasma treatment on GeO2/Ge can inhibit the interfacial layer regrowth by retarding the interdiffusion of Ge and O atoms. The initial ∼1 nm GeO2 layer is consumed during the remote plasma treatment, confirmed by x-ray photoelectron spectroscopy and further thinned down by post-deposition annealing to trigger the GeO desorption.