Due to the need of increasing the gate capacitance of metal-oxide-semiconductor (MOS) devices, the layer thickness of the SiO2 gate dielectric is reducing to such thickness that the leakage current is becoming too large to control. Suitable high-oxides hence need to be found in order to replace the existing gate dielectric, because the thicker layer of the oxide contender may exponentially decrease the tunnelling currents, while achieving the same level of capacitance as the actual devices of SiO2.