Graphitic Carbon Nitride (g-C₃N₄)/Al₂O₃ Heterostructure as Double Dielectric: A Comparative Study in MIS Based on a-IGZO

We present a systematic study of how graphitic carbon nitride (g-C₃N₄) in combination with Al₂O₃ can be used as a double dielectric to control threshold and flat band voltage in capacitance-voltage (C-V) characteristics of an a-IGZO metal-insulator-semiconductor (MIS) device fabricated on ITO substrate. We study temperature dependence of C-V characteristics for Al₂O₃ based MIS structures with and without g-C₃N₄ in the oxide. The effective dielectric constants are estimated in both cases. We show that g-C₃N₄ in combination with Al₂O₃ can be used as an effective dielectric with larger relative permittivity than either of them. It also leads to positive threshold shift without affecting the active interface at the semiconductor. The carrier density in the semiconductor is measured from the depletion region showing small variation with respect to frequency and temperature.