Deposition of AlN at lower temperatures by atmospheric metalorganic chemical vapor deposition using dimethylethylamine alane and ammonia

Abstract

We have studied an atomic layer growth process using amine–alane adducts as precursors for depositing aluminum nitride (AlN) thin films at temperatures between 300 and 800 K. The atomic layer deposition process was carried out in a horizontal metalorganic chemical vapor deposition (MOCVD) reactor at atmospheric pressure using H2 as a carrier gas. Dimethylethylamine alane [(CH3)2(C2H5)N:AlH3] and ammonia (NH3) were used as source gases and sequentially flowed into the reactor with a hydrogen flush between each source gas step. Thin films were deposited onto Si(001) and Al2O3(0001) substrates that were heated on a susceptor by radio frequency induction. Analysis by x-ray photoelectron spectroscopy and x-ray diffractometry revealed deposition of AlN at temperatures as low as 613 K. Processing at lower temperature (510 K) resulted in no detectable AlN deposition while processing at higher temperature (783 K) resulted in nitridation of the Si(001) surface to Si3N4 but no detectable AlN deposition on Si(001) or Al2O3(0001).