Electrical characterization of silicon nitride interlayer-based MIS diode

In this study, silicon nitride (Si₃N₄) thin film on p-type GaAs wafer was deposited by RF magnetron sputtering. The surface morphology of Si₃N₄/GaAs structure was analyzed by atomic force microscopy (AFM). The electrical characteristics of the fabricated Au/Si₃N₄/p-GaAs metal–insulator-semiconductor (MIS) diode were investigated by using current–voltage (I–V) measurements at room temperature. The electronic parameters such as ideality factor (n) and barrier height (Φ_bo) of the MIS diode were derived using thermionic emission (TE). The Φ_bo was also extracted from Norde method. The barrier height values obtained from both TE and Norde were found to be in harmony with each other. The interface state density (N_ss) and series resistance (R_s) parameters of the MIS diode were determined from the measured I–V data. In addition, the dominant current conduction mechanisms of the MIS diode were also investigated by forward bias ln(I_F) − ln(V_F) and reverse bias ln(I_R) − V_R^0.5 plot. At high forward bias, the current conduction was associated with the space charge limited current (SCLC). At reverse bias region, the current conduction was associated with the Schottky emission (SE).