Atomic Layer Deposition of Aluminum Nitride Using Tris(diethylamido)aluminum and Hydrazine or Ammonia

Abstract

Aluminum nitride (AlN x ) films were obtained by atomic layer deposition (ALD) using tris(diethylamido) aluminum(III) (TDEAA) and hydrazine (N2H4) or ammonia (NH3). The quartz crystal microbalance (QCM) data showed that the surface reactions of TDEAA and N2H4 (or NH3) at temperatures from 150 to 225°C were self-limiting. The rates of deposition of the nitride film at 200°C for systems with N2H4 and NH3 coincided: ~1.1 A/cycle. The ALD AlN films obtained at 200°C using hydrazine had higher density (2.36 g/cm3, 72.4% of bulk density) than those obtained with ammonia (2.22 g/cm3, 68%). The elemental analysis of the film deposited using TDEAA/N2H4 at 200°C showed the presence of carbon (~1.4 at %), oxygen (~3.2 at %), and hydrogen (22.6 at %) impurities. The N/Al atomic concentration ratio was ~1.3. The residual impurity content in the case of N2H4 was lower than for NH3. In general, it was confirmed that hydrazine has a more preferable surface thermochemistry than ammonia.