The interaction of hot filament “activated” methane and hydrogen with Si(100) surfaces has been probed in situ for the first time, using Auger electron and thermal desorption spectroscopies. It is shown that hot filament activation of methane results in thechemisorption of acetylene and ethylene on Si (100). Atomic hydrogen drives a range of surface reactions within the adsorbed phases formed. In particular hydrogen abstraction is observed which results in the efficient conversion of ethylene to adsorbed acetylene, and further reactions take place between atomic hydrogen, acetylene and C1 species, resulting in the formation of C3 hydrocarbon species. The implications of this work for diamond film growth are considered, and die results are used to develop a model to describe die growth of sp3 hybridised hydrocarbon chains on the Si surface.

Ultra thin films (< 10 nm) prepared using sputtering or other deposition techniques are becoming more technologically important, with promise of increased importance in the future, particularly in certain magnetic structures. For example, giant-magnetoresistive structures may incorporate individual layers having a thickness < 1 nm. Such a small thickness is commonly associated with relatively short deposition times (∼10 s) and may place limits on the reproducibility and accuracy of the conventional techniques for in situ thickness monitoring or integrated rate monitoring. Experiments have been performed to use laser induced fluorescence (LIF) as a rate monitoring technique for ultra thin films. An RF diode sputtering system was combined with a YAG-pumped, frequency-doubled dye laser to monitor the deposition rale of copper over a range of conditions. When coupled with an absolute calibration reference, the LIF signal gave a reproducible, well-behaved output over a range of pressure and temperature. The technique is potentially advantageous for depositions where rapid (∼1 s) measurements are needed. LIF is also projected to be a valuable tool for detecting very low deposition rates, and it offers the potential of sensitive, real time, spatially-resolved detection in time regimes extending to the nanosecond regime.

The application of ferroelectric oxides in microelectronic and optical devices is critically dependent upon methods to deposit high quality thin films. A major factor influencing the film quality is non-ideal metal stoichiometries caused by process variables. Materials such as PbTiO3 and POZrO3 are well suited for stoichiometric control via molecular precursors having the required metal ratio, eliminating many process variables. Bimetallic precursors for the deposition of lead titanate and PZT thin films have been designed in order to optimize control over the metal stoichiometry. This is accomplished by the synthesis of volatile metalorganic compounds having a 1:1 ratio of Pb:Ti or Pb:Zr. Synthesis and characterization of these novel compounds are presented, and viability for metalorganic chemical vapor deposition (MOCVD) is discussed, based upon decomposition and volatility studies.

The possibility of preparation SmS films by the chemical method from organic compounds has been studied. For this purpose three types of coordinatively-saturated compounds based on dithiocarbamate complexes were synthesized and studied by various methods.

Microwave plasma assisted CVD is employed to grow diamond films using a gas mixture of H2 and CH4on various substrates. Diamond has a tendency not to nucleate growth on mirror-smooth finished substrates irrespective of the substrate type (except single crystal diamond). We have developed various processes to enhance the nucleation density of the diamond substantially by damaging or seeding the surface of the substrates. Several process techniques such as 1. silicon nitride and silicon dioxide process, 2. ultrasonic agitation process, 3. selective seeding of diamond by electroplating of Cu, 4. patterning of diamond films by air-microwave plasma etching, etc., were developed to achieve the patterns of diamond on various substrates. Selective growth of doped diamond and low temperature growth of diamond for microelectronic applications have also been achieved by using the above processes (1 and 2). Details on selective diamond growth processes and the morphology of as-deposited selective diamond by SEM are presented.

Carbon as a constituent of some of the source molecules is always present in the metalorganic growth techniques and can potentially be incorporated into the grown layers. Unintentional carbon incorporation as well as intentional carbon doping of III-V compounds has been studied intensely, especially in the case of GaAs. However, a number of experimental findings still is not well understood. Besides the different electrical behavior of carbon in different host materials (acceptor in GaAs, donor in InAs) also the different probability of incorporation into, for example, GaAs compared to InAs is currently not well explained. Model calculations may provide useful hints to enhance the understanding of the experimentally observed trends. In this paper, two different approaches will be reviewed and their results will be discussed.

The first approach is dealing with the expected incorporation site of carbon in III-V“s. The change in total energy associated with substitutional carbon incorporation onto group III or group V lattice sites has been calculated. From this change the conduction type of carbon doped arsenides and phosphides (except for InAs) can correctly be predicted. While this method is dealing with the bulk semiconductor, the second approach attempts to model the binding energy of methyl to atoms on the growing surface. By using appropriate molecules the methyl bond strength can be estimated. Both approaches together provide a basis for a more complete understanding of carbon incorporation behavior in III-V compounds.