| Materials and thin film processing development has been and remains key to continuing to make ever smaller, or miniaturized, microelectronic devices. In order to continue miniaturization, conformal, low-temperature deposition of new electronic materials is needed. Two techniques capable of conformality have emerged: chemical vapor deposition (CVD) and atomic layer deposition (ALD). Here, two processes for deposition of materials which could be useful in microelectronics, but for which no low-temperature, conformal process has been established as commercializable, are presented. One is ruthenium, intended for use in interconnects and in dynamic random access memory electrodes, a known material for use in microelectronics but for which a more conformal, yet fast process than previously demonstrated is required. The other is manganese nitride, which could be used as active magnetic layers in devices or as a dopant in materials for spintronics, which is not yet established as a desired material in part due to the lack of any previously known CVD or ALD process for deposition.;A unique challenge arises in trying to grow impurity-free films of a catalyst. Ruthenium metal activates C-H and C-C bonds, which aids C-H and C-C bond scission. This creates a potential catalytic decomposition path for all metal-organic CVD precursors that is likely to lead to significant carbon incorporation.;Metallic ruthenium films can be grown by chemical vapor deposition from the organometallic precursor tricarbonyl(1,3-cyclohexadiene)ruthenium(0). This precursor is a highly volatile liquid, easy to synthesize and handle, and capable of delivering at least 0.26 Torr partial pressure at room temperature without the use of a carrier gas. Because the precursor is a liquid, the vaporization rate is not subject to the problem of diminishing surface area that occurs with solid precursors. CVD proceeds readily for substrate temperatures ≥ 200°C. The growth rates are high, up to 24 nm/min, which affords reasonable growth times of only a few minutes for film thicknesses of 50--100 mn. The catalytic activation of C-H and C-C bonds on ruthenium surfaces results in severe carbon contamination, around 30 atomic percent. The films are crystalline, and exhibit persistent (0 0 0 1) texture at low temperatures on all substrates used. The electrical resistivities of the films range from 24 to 219 microO · cm. The increase in resistivity above the bulk value of 7.1 microO · cm can be attributed to grain boundary scattering and the high carbon contamination levels. Films nucleate readily on covalent and oxide materials, in contrast to previously reported Ru precursors that require pretreatment of the substrate surface. The conformality of the films is excellent, even in trench structures with aspect ratios of 20:1.;Manganese nitride films were grown by chemical vapor deposition from the volatile manganese(II) amido precursor bis[di(tert)-butyl)amido]manganese(II)and ammonia. Between 80 and 200°C, the films grown from bis[di(tert )-butyl)amido]manganese(II)contain crystalline eta-Mn3N 2. At 300°C, a mixture of eta- and xi-phase manganese nitride with a manganese carbide impurity is deposited. Oxygen and carbon contamination in the bulk of the films is less than 1 atomic percent. Remarkably, the films are nearly completely crystalline at growth temperatures of 200°C and above. The growth rate of 5.9 nm/min at 200°C is also remarkably high for such a low growth temperature. The crystallinity and rapid growth rates are attributed to the labile metal-ligand bonding characteristic of high-spin MnII. As a result, reactive surface species remain mobile on the surface throughout much of the reaction pathway leading to nitride growth, and can settle into low-energy ordered arrangements before they become incorporated into the bulk by subsequent deposition activity. |
