NEW LIQUID PRECURSORS FOR CVD OF METAL-CONTAINING MATERIALS

摘要

CVD processes are often limited by the available choice of chemical precursors. For many main-group metals, there have been no suitable compounds available to serve as CVD precursors. Only inconvenient solid sources have been known for the alkali and alkaline earth metals. Liquid sources for magnesium, aluminum, gallium and zinc have been dangerously pyrophoric. CVD precursors commonly used to supply transition metals such as titanium and tungsten contain corrosive halogens such as chlorine or fluorine. Many CVD precursors only react at temperatures too high for use with desired substrates. Recent advances in precursor design and synthesis have now removed these limitations. During the past several years, my research group has synthesized and tested new liquid precursors for more than 30 metals. The precursors have been used for low-temperature CVD of their nitrides and oxides, as well as some pure metals. This paper reviews the results of this work. Many of these new liquid precursors are now commercially available, and some are in widespread use for commercial production of coatings.