Synthesis and Characterization of Cross-Linked Nanocomposite as a Gate Dielectric for p-Type Silicon Field-Effect Transistor

Abstract

A good cross-linking between a povidone–silicon oxide nanocomposite has been created using a polar solvent. Furthermore, the effect of annealing temperatures (150°C, 200°C, and 240°C) on the solution-processed povidone–silicon oxide dielectric films has been studied. Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy were applied to identify the chemical interactions of the nanocomposite. Morphology of the thin films was examined using atomic force microscopy. Electrical parameters of field effect transistors (FETs) were calculated on the basis of the information obtained from current–voltage (I–V) and capacitance–voltage (C–V) measurements in the metal–insulator–semiconductor structure. Nanocomposite films had very low surface roughness (0.036–0.084 nm). Si-O-Si and Si-O-C covalent bonds as well as Si-OH hydrogen bonds were formed in the nanocomposite structure. High hole mobilities (1.15–3.87 cm² V⁻¹ s⁻¹) and low leakage current densities were obtained for the p-type Si FETs. The decrease in the Si-OH hydrogen bonds in the dielectric film annealed at 150°C led to a decrease in capacitance and leakage current as well as threshold voltage, and resulted in an increase in mobility and on/off current ratio. By further increasing the annealing temperatures (200°C and 240°C), the binding energies of all the bonds were shifted toward lower values. Therefore, it was concluded that many bonds could have degraded and that defects might have formed in the dielectric film nanostructure leading to a decline in the electrical parameters of the FETs.