Epitaxial growth of AlN thin films on silicon (111) substrates by pulsed laser deposition

Abstract

Aluminum nitride thin films have been grown epitaxially on Si(111) substrates, for the first time, by pulsed laser ablation of sintered AlN target. The influence of process parameters such as laser energy density, substrate temperature, pulse repetition rate, nitrogen partial pressure, etc. on epitaxial growth has been investigated to obtain high quality AlN films. These films were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, x-ray diffraction (Θ and ω scans) technique, high resolution transmission electron microscopy, and scanning electron microscopy. The films deposited at laser energy density in the range of 2–3 J/cm2, substrate temperature of 750 °C, and base pressure of 3×10−7 Torr are single phase and highly oriented along c axis normal to the Si(111) planes. The results of x-ray diffraction and electron microscopy on these films clearly show the epitaxial growth of the AlN films with an orientational relationship of AlN[0001] ∥ Si[111] and AlN[21̄1̄0] ∥ Si[011̄]. The AlN/Si interface was found to be quite sharp without any indication of interfacial reaction. Laser physical vapor deposition is shown to produce high quality epitaxial AlN films with smooth surface morphology when deposited under optimized conditions.

Preparation of the group III nitride thin films AlN, GaN, InN by direct and reactive pulsed laser ablation

“…The strong peaks of the phonon modes indicate that the composition of the film is mainly AlN. Raman spectroscopy was carried out by Vispute et al [54,55] two spectra show the phonon mode with the frequencies in agreement with results reported above. These results clearly show that the laser deposited films contain pure AlN.…”

“…These results clearly show that the laser deposited films contain pure AlN. The AlN band-gap was measured from the optical absorption spectra and results to be 6.15 eV in agreement with that of crystalline AlN (6.2 eV) [42,55]. An Auger spectrum depth profile was obtained for an AlN film grown by laser ablation.…”

Laser technology for synthesis of AlN films: influence of the incident laser fluence on the films microstructure

“…Extensive research is still necessary to find out exactly how the crystallographic structure and degree of crystallinity of AlN films depend on the film preparation method and conditions. Vispute et al reported the synthesis of h-AlN with (0001) orientation [6], while Zhu et al obtained cubic AlN films [8]. Metastable c-AlN was found in films synthesized by nitrogen-ion-assisted pulsed laser deposition [7].…”

“…Moreover, AlN films deposited on Si are promising as microelectronic components thanks to their high dielectric constant and thermal conductivity, thermal and chemical stability, and good lattice match with SiC and GaN. However, obtaining AlN films with definite structure and crystalline quality still remains a challenge for most deposition techniques, such as metal organic chemical vapor deposition [1], reactive magnetron sputtering [2,3] and pulsed laser deposition (PLD) [4][5][6][7]. Extensive research is still necessary to find out exactly how the crystallographic structure and degree of crystallinity of AlN films depend on the film preparation method and conditions.…”

Development of Production PVD-AIN Buffer Layer System and Processes to Reduce Epitaxy Costs and Increase LED Efficiency

“…The equipment used for Si surface preparation is shown in Figure 13 and included a wet bench, an automated spin rinse dry, and of course a monitored DI water supply. After implementing a standard wet clean procedure [25,26], defect free AlN films could be deposited. GaN epilayers were subsequently deposited with no evidence of melt back (Figure 14).…”