Influence of substrate temperature on electrical and optical properties of hydrogenated boron carbide thin films deposited by rf sputtering

Abstract

Amorphous hydrogenated boron carbide films were deposited on silicon and glass substrates using radio frequency sputtering. The substrate temperature was varied from room temperature to 300◦C. The substrate temperature during deposition was found to have significant effects on the electrical and optical properties of the deposited films. X-ray photoelectron spectroscopy (XPS) revealed an increase in sp2-bonded carbon in the films with increasing substrate temperature. Reflection electron energy loss spectroscopy (REELS) was performed in order to detect the presence of hydrogen in the films. Metal-insulator-metal (MIM) structure was developed using Al and hydrogenated boron carbide to measure dielectric value and resistivity. Deposited films exhibited lower dielectric values than pure boron carbide films. With higher substrate deposition temperature, a decreasing trend in dielectric value and resistivity of the films was observed. For different substrate temperatures, the dielectric value of films ranged from 6.5–3.5, and optical bandgap values were between 2.25–2.6 eV.