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Thermal donors in oxygen implanted float-zone silicon have been studied in an experiment to analyze their structure, growth and destruction. Laser annealed oxygen implanted samples were analyzed through ion mass spectrometry, transmission electron microscopy, spread resistance probe and Hall effect. The thermal data collected show that the oxygen-implanted layer had both old and new thermal donors. Thermal donor quantity increases in carbon-oxygen implants. Needlelike precipitates were observed in samples with only an oxygen implant, after thermal annealing, while the carbon-oxygen implants displayed platelet defects.

Contact less measurements of the minority carrier “lifetime” and the photoconductivity are widely used to characterize the material quality and to investigate defects in a sample. In order to interpret these measurements correctly and to guarantee comparability between different methods, numerical simulation tools were developed. These simulations allow to account even for very complex defect models, thus, e.g., enabling the simulation of trapping effects. Contrary to the Shockley–Read–Hall model or the widely used simulation tool PC1D nearly no assumptions are made. Furthermore, nonsteady state solutions can be obtained. The simulation approach is explained in detail, along with simulations of the trapping effect on the measured lifetime for different injections, trap parameters, and measuring methods, demonstrating the capabilities of the here presented simulation tool. Temperature and injection dependent lifetime measurements were performed and it is shown how important sample parameters can be extracted using the simulation tool. Additionally an approach is presented to simulate lifetimes for thick samples, where a nonuniform carrier profile has to be taken into account. This enables a comparison of nonsteady state to steady-state lifetime measurement techniques even for thick samples such as ingots. [ABSTRACT FROM AUTHOR]

We present a simple and highly versatile protocol for polymer ablation: hard x-ray irradiation makes it possible to rapidly depolymerize hyaluronan hydrogels and fabricate three-dimensional network of microchannels. Photodynamic and photochemical analyses show that x-ray irradiation directly cleaves the polymer backbone and the total dose controls the degradation kinetics. This nonthermal ablation protocol may offer opportunities for processing organic polymers and biological materials. [ABSTRACT FROM AUTHOR]

Numerical simulations tools are developed for studying the minority carrier lifetime and the photoconductivity. An approach is described for simulating lifetimes for thick samples, thus enabling a comparison of nonsteady state to a steady-state lifetime measurements techniques.

Presents a study that investigated the rapid thermal annealing of thermal donors in silicon by infrared absorption and resistivity measurements. Information on a tool used for investigating defect annealing mechanisms in solids; Illustration of wafer position and temperature response for a wire thermocouple embedded in silicon within the heat pulse system.

Explains the quasiequilibrium, morphological and structural characteristics of thermally induced oxide precipitates in Czochralski silicon. Information on Czochralski silicon; Thermal annealing of Czochralski silicon; Morphological and crystallographic characteristics of stacking faults in doped Czochralski silicon materials.

Presents a study which characterized the electrical properties of mercury[sub1-x]cadmium[subx]tellurium grown by organic vapor phase epitaxy. Experimental details; Results and discussion; Conclusion.

Presents a study on surface photovoltage measurement of long diffusion length silicon. Limitations of the surface photovoltage method; Principal source of error in thin wafers of long diffusion length material; Possibility of measuring large diffusion lengths in a reliable manner.

Studies the effect of heavy boron doping upon oxygen precipitation in Czochralski silicon. Information on the x-ray theoretical considerations; Details on the experiment; Bragg line profiles; Conclusions.

Presents information on a study which investigated the impact of high carbon concentration on oxygen precipitation and related phenomena in Czochralski silicon (CzSi). Enhancement of oxygen precipitation; Thermodynamic and kinetic aspects of oxygen precipitate morphology in high carbon content; Experimental details; Results and discussion; Conclusions.

Comments on an article which investigated the annealing of thermal donors at different temperatures in order to determine an activation energy for the process. Analysis of previous data using an implicit assumption of first-order decay kinetics; Value for the activation energy; Information on how the order of kinetics of a chemical reaction should be examined.