Study on Reaction Mechanism of Aluminum Selective Chemical Vapor Deposition with In-situ XPS Measurement

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Aluminum (Al) films have been deposited selectively on Si at a substrate temperature from 270 to 330℃ under 1×10^<-3> Torr employing dimethylaluminum hydride (DMAlH). The experiments were carried out in a reaction chamber connected to an X-ray photoelectron spectroscopy (XPS) analyzer. The origin of selectivity was studied by in-situ XPS analysis, dopant dependency and surface treatments. The selectivity was independent of the dopant type and its concentration in Si substrate. In-situ XPS measurement revealed that the Al-hydrogen (H) bond was broken only on the Si surface. No Al film grew on the Si surface subjected to Ar^+ ion bombardment, while the Si surface exposed subsequently by hydrogen radicals was allowed to deposit the Al film. Eventually, it is considered that hydrogen (H) and/or fluorine (F) which terminates the Si surface after dipping in HF solution reacts with H atoms and methyl group in DMAlH, leading to the selective deposition of Al. Al did not grow on SiO_2 and Al_2O_3 surfaces because of the easy oxidation of Al due to the reaction of Al with oxide surfaces. Al could deposit on the TiN surface after the native oxide was reduced by hydroden radicals.
社団法人応用物理学会の論文
1990-11-20