INFRARED REFLECTION-ABSORPTION SPECTRA OF TRIMETHYLALUMINUM AND DIMETHYLALUMINUM HYDRIDE CONDENSED LAYERS ON AN SIO2 SURFACE WITH A BURIED METAL LAYER SUBSTRATE

Infrared reflection absorption spectroscopy (IRAS) of trimethylaluminum (TMA) and dimethylaluminum hydride (DMAH) layers condensed on an SiO2 surface was carried out by using a buried metal layer (BML) substrate. TMA was a dimer in the experimental temperature range of 110 K < T < 160 K. The molecular orientation varied depending on the deposition temperature. The condensed layer of DMAH as-deposited at the temperature ranging from 110 to 130 K was a mixture of trimers and dimers. The dimers changed to trimers as the temperature increased, practically disappearing above 130 K. This temperature dependence was not reversible. The trimers did not change to dimers below 130 K. The ordered orientation of the trimer molecules was a stable DMAH condensed layer structure on the SiO2 surface. The usefulness of BML-IRAS for studying the structure and molecular orientation of adsorbed layers on semiconductor materials is discussed.