Analyzed electrical performance and induced interface passivation of fabricated Al/NTCDA/p-Si MIS–Schottky heterojunction

Abstract

In this research, the significant role of 1,4,5,8-naphthalenetetracarboxylic-dianhydride, NTCDA, thin film on the Al/p-Si barrier under different temperatures is investigated. The structural and topographical properties of the thermally evaporated NTCDA thin film are investigated using a transmission electron microscope, TEM, and atomic force microscope, AFM, respectively, and elucidated that the fabricated films have a smooth nanocrystalline nature with an average crystallite size about 89 nm and average roughness about 3.15 nm. Furthermore, the current–voltage (I–V) characteristics of Al/NTCDA/p-Si/Al device are studied under dark conditions at different temperatures (313–383 K). The Schottky diode electronic parameters such as ideality factor, n, barrier height, ΦB, and reverse saturation current, Is, are calculated at each temperature. A clear increment of ΦB from 0.74 to 0.88 eV accompanied by a clear decrement of n values from 5.83 to 4.99 under increasing temperature (313–383) K is noticed. Due to the inhomogeneity of barrier height, the Gaussian distribution of Schottky barrier height is employed to estimate the mean value of barrier height and standard deviation and found to be 1.5 eV and 20 mV, respectively. The modified Richardson plot is used to estimate the modified Richardson constant and found to be 35.2 A cm−2 K−2 which is close to the known value of p-Si. Moreover, the conduction mechanism in forward and reverse biasing is explained in details. The modified Norde's function is employed for estimating the series resistance, Rs, and barrier height of the fabricated device at each temperature, where the values of Rs showed a decrement behavior from 3.564 to 1.165 kΩ upon increasing the temperature. The process of inserting NTCDA between electrode and p-Si influenced the distribution of interface states for MIS Schottky diode at different temperatures and is explained as a passivation process of the device's interface states.