Poly(melamine-co-formaldehyde) methylated effect on the interface states of metal/polymer/p-Si Schottky barrier diode

Abstract

The deposition technique and interface effect of polymeric molecules onto silicon surface is crucial topic for organic/inorganic hybrid technologies. In this study, the chemical structure of poly(4-vinyl phenol) (PVP) has been modified by cross-linked agent in solution for deposition onto p-Si surface. The poly(melamine-co-formaldehyde) methylated (PMF) has been used as a cross-linked agent for PVP polymeric molecules to apply spin cast deposition technique. The rectification ratio and interface states have been improved with PMF cross-link agent compared with only PVP polymeric layer. Some important diode parameters such as diode ideality factor (η), barrier height (ϕb), interface state density (Nss), series resistance (Rs) of the Au/PVP:PMF/p-Si structure were calculated from the current–voltage (I–V) characteristics. The ideality factor and barrier height were found to be 2.37 and 0.71. For the explanation of the deviation of ideality factor value from 1, the interface states has been investigated by the frequency dependent capacitance (C–f–V) and conductance (G–f–V) techniques at room temperature. It is found that the interface states and Rs which indicate the deviation of the ideality factor of Au/PVP:PMF/p-Si structure is strongly depended on bias voltage and frequency.