Influence of sputtering conditions on crystalline quality of AlN layers deposited by RF reactive sputtering

Abstract

AbstractAluminum nitride (AlN) is increasingly demanded for use in semiconductor‐related industries. This study was undertaken for fabrication of high‐quality AlN thick layers using radio‐frequency (RF) reactive sputtering with a pure Al target. The AlN layers were sputtered homoepitaxially on high‐quality thin AlN layers on sapphire substrates for 1.5 h with 300 to 650 W at 573 and 773 K. The AlN thin layers were grown using sapphire nitridation before sputtering. A N2‐Ar gas mixture was used as the sputtering atmosphere and N2 gas flow ratio was changed from 20 to 60 vol%N2. In all sputtering conditions c‐axis oriented AlN layers were fabricated. AlN layer sputtered with 400 W under 40 to 60 vol%N2 at 773 K was grown by about 1 μm thickness. The AlN layer sputtered with 400 W under 40 and 50 vol%N2 at 573 and 773 K showed superior quality, with almost identical crystal structural quality to that of each nitrided sapphire substrate. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)