Growth of ZnO thin film on SiO_2 substrates by the RF magnetron sputtering method

摘要

In recent years, ZnO thin films have been extensively studied for surface acoustic wave (SAW) devices, optical wave-guides, and transparent conducting coatings 1. Since ZnO has a wide band gap of 3.37 eV, low power threshold for optical pumping at room temperature, and UV emission resulting from a large exciton binding energy of 60 meV, it can be used in light emitting diodes (LED), photodetectors, electroluminescence devices and the next generation of UV lasers. ZnO films have been grown by various deposition methods, such as sputtering 2, sol-gel process 3, spray pyrolysis 4,5, pulsed laser deposition 6,7, ion beam deposition 8, plasma enhanced chemical vapor deposition (PECVD) 9, atomic layer deposition (ALD) 10, filtered cathodic vacuum arc technique 11, evaporation 12, metal-organic chemical vapor deposition (MOCVD) 13, and molecular beam epitaxy (MBE) 14. Among them, one of the most commonly used techniques is a sputtering method due to its simplicity and the possibility of obtaining good orientation and uniform films even on amorphous substrate or at low growth temperature. Since amorphous substrates such as SiO_2 and glass substrate have obvious technological advantages and potential applications 15, we have grown ZnO film on SiO_2 substrate using a RF magnetron sputtering system. Although many researchers have grown ZnO films on sapphire, Si or glass substrates, there are few reports on growing ZnO thin films on SiO_2 using a RF sputtering technique.