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A model has been developed for the rapid melting and resolidification of thin Si films induced by excimer-laser annealing. The key feature of this model is its ability to simulate lateral growth and random nucleation. The first component of the model is a set of rules for phase change. The second component is a set of functions for computing the latent heat and the displacement of the solid–liquid interface resulting from the phase change. The third component is an algorithm that allows for random nucleation based on classical nucleation theory. Consequently, the model enables the prediction of lateral growth length (LGL), as well as the calculation of other critical responses of the quenched film such as solid–liquid interface velocity and undercooling. Thin amorphous Si films with thickness of 30, 50, and 100 nm were annealed under various laser fluences to completely melt the films. The resulting LGL were measured using a scanning electron microscope. Using physical parameters that were consistent with previous studies, the simulated LGL values agree well with the experimental results over a wide range of irradiation conditions. Sensitivity analysis was done to demonstrate the behavior of the model with respect to a select number of model parameters. Our simulations suggest that, for a given fluence, controlling the film’s quenching rate is essential for increasing LGL. To this end, the model is an invaluable tool for evaluating and choosing irradiation strategies for increasing lateral growth in laser-crystallized silicon films.

Thin HfO2 films have been deposited on silicon via atomic layer deposition using anhydrous hafnium nitrate [Hf(NO3)4]. Properties of these films have been investigated using x-ray diffraction, x-ray reflectivity, spectroscopic ellipsometry, atomic force microscopy, x-ray photoelectron spectroscopy, and capacitance versus voltage measurements. Smooth and uniform initiation of film growth has been detected on H-terminated silicon surfaces. As-deposited films were amorphous, oxygen rich, and contained residual NO3 and NO2 moieties from the nitrate precursor. Residual nitrates were desorbed by anneals >400 °C, however, the films remained oxygen rich. Crystallization of thin films (

Thin (∼10 nm) films comprising of Ta2O5–HfO2, Ta2O5–ZrO2, and ZrO2–HfO2 nanolaminates were deposited and characterized for possible gate dielectric applications. These films were deposited on silicon substrates using atomic layer deposition. The dielectric constants of these films were in 12–14 range and the leakage currents in 2.6×10−8–4.2×10−7 A/cm2 range at 1 MV/cm electric field. It was found that as these films were made thinner, the value of their dielectric constant dropped compared to their bulk values. The dominant leakage current mechanism at low electric fields was determined to be Schottky emission, whereas Poole–Frenkel emission dominated at higher fields.

A thorough investigation of polysilicon films crystallized from amorphous silicon using a XeCl excimer laser has been completed. Emphasis was placed on the development of large crystals, good uniformity, and low surface roughness, with an eye towards improving throughput. This was accomplished through use of SiO2 barrier layers, multiple passes, and careful consideration of annealing ambient. Thermal modeling was performed to help interpret the observed trends and aid in optimization. By controlling these process parameters, samples were produced with a high degree of uniformity and two-dimensional structural ordering, with grains nearly identical in size and stacked in rows and columns. However, a biproduct of the ordering was the creation of large topographical features at the intersection points of multiple grain boundaries, which lead to surface roughness in the range of 12 nm. By applying more shots to the same area, films with maximum grain sizes on the order of 3 μm and reduced surface roughness (6...

A sequential pulsed process is utilized for deposition of nonstoichiometric silicate films without employing an oxidizing agent. The metal precursors were HfCl4, AlCl3, and ZrCl4, as well as Hf(NO3)4 and the silicon source was tris(tert-butoxy)silanol. Unlike atomic layer deposition, the growth per cycle was several monolayers thick, where the enhancement in growth was due to a catalytic reaction. The bulk and electrical properties of these films are similar to those of silicon dioxide. Silicon carbide devices coated with these films show good insulating characteristics.

The effect of UV laser radiation on the emission of a ZnS:Tb thin film electroluminescent (EL) device has been investigated. It was found that the EL emission can be enhanced near threshold and attenuated at higher voltages by irradiating the device with UV radiation from an argon ion laser. It is shown that these effects are related to the photogenerated carriers that alter transport and build up of charge and the electric field. Both the charge and the field have been determined in real time to examine the enhancement and attenuation of the EL emission.

Periodic structures have been obtained during nominally unpolarized excimer laser (ArF)‐assisted organometallic vapor phase epitaxy of GaP on GaAs. Both crystalline properties and chemical composition of these structures have been examined. The chemical analysis showed a variation in composition across a ripple which was attributed to the modulated thermal profile due to interference.

Ultraviolet photon‐assisted metalorganic vapor‐phase epitaxy has been used to grow CdTe, followed by Hg1−x Cdx Te on GaAs/Si substrates at 250 °C in order to fabricate Hg1−xCdxTe/CdTe/GaAs/Si structures. For Hg1−xCdx Te growth methylallyltelluride, a new Te precursor, is used to obtain growth rates of 4 μm/h. X‐ray rocking curves and transmission electron microscopy are utilized to characterize the crystalline properties of the epilayers and Hall measurements to determine the electrical properties. Hall electron mobilities of Hg1−x Cdx Te (for x∼0.2) are typically 4×104 cm2 /V s at 80 K.

Homoepitaxy of CdTe using ultraviolet photon‐assisted metalorganic vapor‐phase epitaxy has been investigated at 250 °C with dimethylcadmium and diethyltellurium as the precursor gases. Empirical relationships between film properties and the deposition parameters at high growth rates (> 4 μm/h) are examined.