This article proposes a methodology to control the growth of unwanted interfacial layer (IL) at the time of deposition of high-kappa-based gate oxide materials on silicon using reactive RF sputtering technique. Different negative dc biases are applied across a copper grid, placed near the substrate in order to prevent O radicals from reaching the Si substrate. This improvised technique prevents reaction between the O radicals diffusing through the already deposited high-kappa film with the underlying Si substrate. The X-ray reflectivity (XRR) studies show that minimum IL is achieved when a negative voltage bias of -200 V is applied across the grid. The reduction of IL also improves the electrical performances of the metal-oxide-semiconductor (MOS) devices. A simple modification of the sputtering instrument makes the technique more useful for the deposition of oxides on silicon. (C) 2017 Elsevier B.V. All rights reserved.