Transparent conductive oxides have been widely used in optoelectronic devices owing to their special optical property. In near-infrared wavelength region, the real part of the dielectric constant will decrease from positive to negative. Within epsilon-near-zero (ENZ) region, strong interaction will occur between light and matter, and wide phase modulation will be achieved. Herein, using a bias voltage of 0-5 V, the carrier concentration within a region (thickness: 1 nm) near the interface of an ITO-based MOS structure was adjusted, and a phase modulation close to 265° in a 1470-nm wavelength was achieved. Based on this modulation, the practical applications of the proposed structure in the fields of beam deflection and focusing have been explored. Furthermore, a dual-gated MOS structure, which further expanded the phase coverage region, was designed.