ELSEVIER December 1997 Materials Letters 33 (1997) 133-136 Reactive partially ionized beam deposition of AlN thin films Jiayou Feng *, Junqing Xie, Qingwei MO zyxwvutsrqponmlkjihgfedcbaZY Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, PR China Received 11 March 1997; accepted 20 March 1997 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSR Abstract Aluminum nitride films were synthesized on zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFE Sic11 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIH 1) wafer and quartz by the reactive partially ionized beam (RPIB) deposition technique. Under specific experimental conditions, polycrystalline and preferential crystalline AlN films of hexagonal structure were obtained by this method. The correlation between experimental parameters and the resulting structure as well as the stoichiometry of the AlN film are discussed. 0 1997 Elsevier Science B.V. Keywords: AIN films; Deposition; Reactive partially ionized beam method The interest in AIN thin films stems from their desirable electrical, optical, dielectric and acoustical properties [I]. Various techniques have been reported for the synthesis of AlN films. These include met- alorganic chemical vapor deposition (MOCVD) [2], reactive sputtering [3,4], pulsed laser deposition (PLD) [5] and ion beam assisted deposition (IBAD) [6], etc. In the present work, AlN films were formed for the first time by the reactive partially ionized beam (RPIB) depos.ition technique 171, using Al as the evaporation material and N, as the reactive gas. The structure of the deposited films was character- ized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). AlN films were grown by a home-designed ion- ized cluster beam deposition (ICBD) system [gl. High-purity Al (99.999%) was loaded in a BN cru- cible, of about 20 mm in diameter and with the top * Corresponding author open. During deposition, the crucible was heated to 1400- 1600°C by a spiral tungsten filament. The base pressure was 2 X 1O-6 Torr and the partial pressure of nitrogen during the deposition was 3 X 1O-4 Torr due to N, gas feeding the chamber. The ionizer was composed of a heating filament and a grid. The evaporated species and reactive gas were partially ionized by electron beam bombardment and acceler- ated to the substrate reacting to form a AlN com- pound with enough energy. The optimum electron current for ionization in this experiment was found to be 200 mA. The acceleration voltage, i.e. substrate bias potential, was selected to be 0.4, 1 and 2 kV for comparison. AlN films were deposited on Sic 111) wafer and quartz substrates. The whole Si substrates had been cleaned with the standard procedure of etching in H,SO,:H,O, (1:l) and HF:H,O, (1:l) mixed solu- tion for 5 min. The substrate temperature was 200°C during the deposition, the deposition rate was con- trolled at 0.1-0.2 rim/s and the thickness of films ranged from 100 to 200 nm. 00167-577X/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. PII SO167-577X(97)00088-8