Tadaaki Yako

Aluminum chemical vapor deposition reaction of dimethylaluminum hydride on TiN studied by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry

To understand the nucleation mechanisms of aluminum film during chemical vapor deposition (CVD), the reactions of dimethylaluminum hydride (DMAH) with oxidized TiN and Si surfaces were studied by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). It was observed that DMAH exposure reduced the native oxide on the TiN surface, resulting in a clean TiN surface. The reduction of the native oxide and the deposition of Al on the TiN surface were enhanced with increasing DMAH dose. In contrast with the reaction on the TiN surface, no reduction of native oxide by DMAH exposure was observed on the Si surface except at the uppermost surface level analyzed by TOF-SIMS. The amount of Al deposited on the oxidized Si surface was less than that on the oxidized TiN surface under the same experimental conditions and was largely independent of the amount of DMAH dose over the studied range. The reduction of native oxide and the appearance of a clean TiN surface are thought to be important in accounting for the nucleation mechanism and the improved surface morphology of Al film deposited on TiN surfaces using the CVD process.

In situ monitoring of Al growth in chemical vapor deposition by detecting reflected laser light intensity

A nondestructive, noncontact monitoring method has been developed for Al chemical vapor deposition (CVD). This monitoring method involves irradiating He-Ne laser light on the substrate surface and detecting the reflected light intensity. The intensity changes with deposition time corresponded to the following stage of Al island formation, island coalescence, continuous smooth film formation, and surface roughening. The effectiveness of this method was demonstrated by applying it to Al growth on both in situ sputtered Ti and SiO2 pretreated with tetrakisdimethylamino-titanium for nucleation enhancement.