Reaction of dimethylethylamine alane and ammonia on Si(100) during the atomic layer growth of AlN: static SIMS, TPSIMS, and TPD

Dimethylethylamine alane [DMEAA; AlH3:N(CH3)2(CH2CH3)] has been used as an Al source in the chemical vapor deposition of AlN. In the atomic layer growth mode, ammonia and DMEAA interact selectively by nucleophilic displacement. In the first part of this study, the surface adsorption and reaction processes are characterized with static secondary-ion mass spectrometry and temperature-programmed secondary-ion mass spectrometry. The secondary ion emission from DMEAA-covered Si surface shares similar general characteristics with the gas phase cracking pattern. The secondary ion emission spectrum is interpreted according to a unimolecular ion decomposition mechanism and is used as the fingerprint for the presence of molecular DMEAA. During the surface reaction between DMEAA and ammonia, the intensity of the fingerprint peaks diminish, representing the departure of the amine ligand. The thermal stability of DMEAA and its decomposition behavior on Si are also examined.