Trimethylgallium Decomposition on Si(100)

Publisher Website
Google Scholar
Abstract
The decomposition of trimethylgallium (TMG) on Si(100) is examined with temperature programmed desorption (TPD), x‐ray photoemission spectroscopy (XPS), and Auger electron spectroscopy (AES). It is found that carbon incorporation is an intrinsic part of the TMG decomposition process. The TPD spectrum of adsorbed TMG shows a broad methane feature between 300 and 800 K. There is also a hydrogen peak which shifts from 780 to 800 K with increasing TMG coverage, and a gallium peak at 970 K. Molecular TMG desorption is also seen at TMG coverage above . No desorption of methyl radicals or higher hydrocarbons was detected in these experiments. Nonetheless, methyl radical desorption at temperatures above 800 K cannot be excluded. XPS shows that the TMG is molecular below 500 K. However, the TMG starts to decompose at about 550 K. Two‐thirds of the carbon in the TMG desorbs while one‐third remains behind on the surface. The decomposition ratio is independent of the TMG coverage, the surface hydrogen concentration, and the state of the surface. Further, no incorporation of surface hydrogen into the methane desorption product is observed. These results show that the decomposition of TMG is an intramolecular process. Two of the methyl groups react with the hydrogens on the third methyl group to yield methane. There is not enough hydrogen in the TMG to hydrogenate the third methyl group. As a result, the remaining carbon gets incorporated into the surface.

This publication has 0 references indexed in Scilit: