Growth of conductive and insulative highly-orientated aluminum nitride thin films using laser molecular beam epitaxy

Conductive and insulative highly-orientated aluminum nitride thin films were grown on Si (111) and sapphire (0001) substrates using laser molecular beam epitaxy by only changing the nitrogen pressure. The microstructure of AlN films was characterized by X-ray diffraction and scanning electron microscopy, while the electrical and optical properties were measured by current–voltage, capacitance–voltage and ultraviolet–visible-near infrared spectroscopy. The results show that the AlN films deposited under 1 Pa nitrogen pressure are insulative with a resistivity of 1011–1012 Ω·cm, while they become conductive with a resistivity of 9.3 × 10− 1 Ω·cm grown under 2 × 10− 2 Pa because of the presence of aluminum particles. Electric properties of the AlN films are strongly influenced by aluminum particles. The presence of metallic aluminum also decreases the optical transmittance of the AlN films from 85% to 20%.

► Conductive and insulative AlN films have been obtained using LMBE.
► The existing state of aluminum in the films has been studied.
► The electric properties of AlN films are strongly influenced by aluminum particles.
► The optical transmittance of AlN films is decreased by aluminum particles.