A variety of transition-metal films have been grown by organometallic chemical vapor deposition (OMCVD) at low temperatures using hydrocarbon or hydrido-carbonyl metal complexes as precursors. The vapors of the metal complexes are transported with argon as the carrier gas, adding H2 to the stream shortly before contact with a heated substrate.
High-purity platinum films have been grown using (η5−C5H5)PtMe3 [1] or (η5−CH3C5H4)PtMe3 [2] at substrate temperatures of 180°C or 120°C, respectively. The incorporation of a methyl substituent on the cyclopentadienyl ligand decreases the melting point of the organoplatinum complex from 106°C [1] to 30°C [2] and increases the vapor pressure substantially. Film deposition also occurs at a lower substrate temperature. Analyses by X-ray diffraction (XRD), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) indicate that the films are well crystallized and do not contain any observable impurities after sputter cleaning.
The substrate temperatures for the first appearance of other transition-metal films from organometallic precursors are as follows (°C): Rh(η3−C3H5)3 (120/Si), Ir(η3-C3H5)3 (100/Si), HRe(CO)5 (130/Si) and Ni(η5−CH3C5H4)2 (190/glass, 280/Si). These films are essentially amorphous and contain trace oxygen impurities (< 2%), except for the Re film, which was 10% oxygen and 20%carbon.