Low-Temperature Organometallic Chemical Vapor Deposition of Transition Metals

Abstract

ABSTRACTA 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.