Characterization of aluminum oxide films on p-type silicon substrate prepared by glass assisted CO2 laser technique

Abstract

Aluminum oxide (Al2O3) films were deposited on p-type Si 〈100〉 substrate using glass assisted CO2 laser technique. Aluminum trichloride AlCl3 and O2 were used as aluminum and oxygen sources respectively and Ar was used as a carrier gas for AlCl3. The films were deposited at different substrate temperatures ranging from 480 to 830 °C. The effect of thermal annealing on low deposited substrate temperature films was carried out in argon environment. Chemical compositions of the films were studied by using Fourier transform infrared (FTIR) spectroscopy. FTIR spectra showed some characteristic bands of aluminum silicate corresponding to bending and stretching bonds of aluminum oxide in the range 650–750 and 750–850 cm−1 respectively. Energy dispersive X-ray showed presence of aluminum in the films. Capacitance–voltage (C–V) measurements were carried out on MOS devices made of these films. Results indicated density of interface traps D it in the range 1012–1013 eV−1 cm−2. The current density–voltage (J–V) curves of devices suggested Poole–Frenkel and Shcottcky emission mechanisms for carrier transport in MOS devices.