The surface decomposition mechanism of bistrimethylamine aluminium hydride [(Me3N)2 · AIH3] on the Ga-rich (4 × 1) GaAs (100) surface is studied by TDS, HREELS and XPS. It is found that the first monolayer of the complex chemisorbs molecularly at 150 K. The decomposition pathway is shown to involve the activated dissociation of this chemisorbed precursor to produce Al, adsorbed H atoms and trimethylamine. The latter species desorb without further fragmentation and this key feature results in the deposition of carbon-free aluminium films. This contrasts markedly with the decomposition of organometallics like trimethyl aluminium (TMA) which are traditionally used in Al CVD where carbon incorporation is an intrinsic part of the decomposition process. © 1990.
