Ligand stabilised dialkyl aluminium amides as new precursors for aluminium nitride thin films

Abstract

Ligand stabilised aluminium amides of the type Me₂Al[NR′(CH₂)₂NR₂] where R = Me and R′ = Et (1) are synthesised using HNEt(CH₂)₂NMe₂ (1a) via an alkane elimination reaction, with an equimolar mixture of Lewis acid (trimethylaluminium) and Lewis base (substituted ethylenediamine 1a), in the absence of solvent. The product is a colourless liquid having relatively high vapour pressure as indicated by TGA. Metalorganic chemical vapour deposition (MOCVD) of the precursor in the presence of ammonia carried out in temperature range of 500–950 °C resulted in crystalline AlN films. The self decomposition (without ammonia) of the precursor under MOCVD conditions resulted in aluminium (carbo) nitride films having the composition Al∶N∶C 1∶0.7.0.6 (±0.1) above 600 °C using N₂ and H₂ as carrier gas.