Role of charge particles irradiation on the deposition of AlN films using plasma focus device

Highly crystalline AlN films are deposited on Si substrate by the bombardment of charge particles emanating from plasma focus device. Deposition of AlN films are carried out for multiple focus shots at room temperature. Numbers of ions (1.3×1019-5.6×1019 m−3) are emitted during one focus shot. X-rays diffraction results reveal that an amorphous and crystalline AlN films are obtained for 1 and 3 focus shots, respectively. Crystallinity of AlN film increases up to 5 focus shots while it starts to decrease for 15 and 20 focus shots. The average crystallite size of AlN (1 0 0) phase increases from 33 to 140 nm for 3-5 focus shots, whereas it starts to decrease from 26 to 22 nm for 15-20 focus shots. Raman's spectroscopy exhibits the presence of A1 (TO) and E1 (TO) modes at ∼ 611 and ∼ 665 cm−1 positions respectively confirming the formation of AlN film. Fourier's transform infrared spectroscopy indicates the presence of strong absorption peak at ∼ 667 cm−1 position. Field emission scanning electron microscopic investigation reveals that different surface morphologies for different focus shots are observed which are mesh like but uniform for 1 shot, dense microstructure (rounded grains) for 3 shots, rough surface (large particulates) for 5 shots, rounded grains but dense microstructure for 15 shots and multi-layers formation showing rounded grains for 20 shots. Thickness of AlN film deposited for 1 focus shot is uniform and is about 190 nm. Energy dispersive X-ray spectroscopic results show the presence of Al and N elements in AlN film deposited for 5 focus shots.