Several mechanism-related aspects of the corrosion of zirconium alloys have been investigated using different examination techniques. The microstructure of different types of oxide layers was analyzed by transmission electron microscopy (TEM). Uniform oxide mainly consists of m-ZrO2 and a smaller fraction of t-ZrO2 with columnar grains and some amount of equiaxed crystallites. Nodular oxides show a high open porosity and the grain shape tends to the equiaxed type. A fine network of pores along grain boundaries was found in oxides grown in water containing lithium. An enrichment of lithium within such oxides could be found by glow discharge optical spectroscopy (GD-OES) depth profiling. In all oxides, a compact, void-free oxide layer was observed at the metal/oxide interface. Compressive stresses within the oxide layer measured by an X-ray diffraction technique were significantly higher compared to previously published values. Electrical potential measurements on oxide scales showed the influence of the intermetallic precipitates on the potential drop across the oxide. In long-time corrosion tests of Zircaloy with varying temperatures, memory effects caused by the cyclic formation of barrier layers could be observed. It was concluded that the corrosion mechanism of zirconium-based alloys is a barrier-layer controlled process. The protective properties of this barrier layer determine the overall corrosion resistance of zirconium alloys.

Flims of metal oxides, such as Ta2O5, Nb2O5, Al2O3, HfO2, ZrO2 and TiO2 have been fabricated by use of different precursor materials, deposition techniques and annealing techniques. Several analytical methods were applied to study the layers. New data of fundamental properties of these metal oxides are reported and related to practical features that are of importance in device design and manufacturing of advanced, highly integrated devices. This overview may facilitate the choice of an optimal combination of precursor material, deposition technique and corresponding annealing procedure for a specific application of these metal oxide films in microelectronics.

Device quality CuInSe2 thin films have been synthesized by Rapid-Thermal-Processing (RTP) of elemental Cu-In-Se stacked layers. We could demonstrate for the first time solar cells with an efficiency above 10% produced at short heating cycles and without using toxic gases. The microstructure of these films is analysed in detail by SEM, TEM and SIMS. Morphology, crystal quality and solar cell efficiency are influenced drastically by the CdIn atomic ratio. The predominant CIS crystal defects observed in indium-rich films are twins whereas in copper-rich films additionally dislocations, stacking faults and precipitates are observed.

Indium—tin oxide (ITO) applied to optoelectronic devices must meet several requirements simultaneously, i.e. electrical conductivity, optical transparency, and structurability by photolithography. As will be shown, these properties are mainly based on the microstructure of the ITO films. The microstructure changes from amorphous to polycrystalline depending on the oxygen partial pressure in the sputtering ambient and the deposition rate. We investigated the influence of an oxide layer on the target surface, its removal prior to film deposition, and its formation during the sputtering process. The reproducibility of the ITO microstructure and the etching properties are discussed in detail.

The refractory metal disilicides TiSi2 and TaSi2 were investigated for their usefulness as dopant diffusion sources. During furnace annealing and rapid thermal processing, strong decomposition reactions occur between the dopants D (B or As) and the respective silicide (MSi2) to form MxDy compounds. With the help of special sample preparation methods and various analytical techniques, the compound phases TiB2, TiAs, TaB2, and TaAs were unambiguously detected. The fraction of freely diffusing B in TaSi2 is determined to be below 5% of the total dose; by far, the major part of the dopant is bound within the TaB2 phase detected. Careful sample preparation and analysis of secondary-ion-mass spectrometry profiles is necessary to avoid artifacts caused by these compound particles. The MxDy-compound formation has detrimental consequences: The solubility of arsenic and even more of boron in TiSi2 and TaSi2 is limited to rather low-concentration levels (e.g., B in TaSi2: 4 × 1018 B/cm3 < CB(900 °C) < 1.6 × 1019 B/cm3) and the outdiffusion into poly- or monocrystalline silicon is strongly retarded. Also, the low interface dopant concentrations achievable result in unacceptably high values of contact resistance. The observations on metal-dopant- (M-D-) compound formation are demonstrated to agree well with the predictions from thermodynamic calculations on the respective M-Si-D system. The effects on junction formation are compared to the case of WSi2 and CoSi2, which, from a parallel study, are known not to form compounds. In all cases these comparisons support our statements on the tremendous impact of M-D-compound formation, because much improved data on diffusion and junction formation were obtained for CoSi2 and WSi2. The same holds for a comparison on contact resistances for silicide diffused junctions, which was performed for TiSi2 and CoSi2.

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Films of tantalum pentoxide (Ta2O5) have been fabricated by use of different precursor materials, deposition techniques and annealing procedures. Several analytical methods were appliedto study the layers. Fundamental properties and new data are reportedand related to practical features that are of importance in device design and manufacturing of advanced, highly integrated devices. This overview may facilitate the choice of an optimal combination of precursor, deposition technique and corresponding annealing procedure for aspecific application of these films in microelectronics, since the electrical properties reveal the potential of Ta2O5 films for the use in 64Mbit and 256Mbit DRAM devices as high dielectric constant material.

A laminar flow low‐pressure chemical vapour deposition (LPCVD) system (LAM IntegrityTM) has been used to deposit tantalum pentoxide (Ta2O5) from Ta(OEt)5 films in the presence of oxygen (O2) at 470 °C at a typical deposition rate of 4 nm min−1. Uniformities of <1.5% (SD 1σ) over a 150 mm silicon substrate were obtained. The layers were annealed under different conditions. It was discovered that the films did not change their stoichiometry as determined by Rutherford backscattering (RBS). The as‐deposited films were amorphous but became crystalline (β‐Ta2O5) at temperatures > 700 °C. The transmission electron microscopy (TEM) results on crystallisation behaviour were supported by X‐ray diffraction data. The electrical properties of the Ta2O5 films have been characterised using MIS (metal/insulator/silicon) capacitor structures. Leakage values of <10−6 A cm−2 at 6 MV cm−1 equivalent applied electric field and breakdown strengths of >7 MV cm−1 at 1.6 μA were obtained for annealed layers. Compound dielectric constants (native silicon oxide thickness of about 2.5 nm plus Ta2O5 of various thicknesses) between 14 and >30 have been measured. The electrical properties reveal the potential use of Ta2O5 as a storage capacitor dielectric in 64 and 256 Mbit DRAM (dynamic random access memory) devices.