Characterization of Oxidation-Induced Stacking Fault Rings in Cz Silicon: Photoluminescence Imaging and Visual Inspection After Wright etch

AbstractOxidation-induced stacking fault rings in polished Cz silicon samples before and after thermal wet oxidation are investigated by use of photoluminescence imaging. Currently the standard procedure for OSF ring detection is to expose the samples to a toxic preferential etchant, e.g. a Wright solution, after a thermal oxidation. This solution primarily attacks the regions with stacking faults, allowing detection by visual inspection. Samples from the seed end of p-type Cz silicon ingots with resistivities of approximately 1Ohm-cm were measured by PL imaging before and after a thermal oxidation process. Subsequently, Wright-etching was performed on the oxidized samples to expose stacking faults. The lifetime variations in the PL images were correlated with the location of the rings in the preferentially etched surfaces, and good agreement was found. The results show that for this crystal pulling process, even the PL images of unpassivated polished samples can be used to detect the OSF ring location. The thermal oxidation at 1100°C enhanced the contrast between the OSF ring and the rest of the sample in the PL image

The development of complex sentence interpretation in typically developing children compared with children with specific language impairments or early unilateral focal lesions

This study compared sentence comprehension skills in typically developing children 5–17 years of age, children with language impairment (LI) and children with focal brain injuries (FL) acquired in the pre/perinatal period. Participants were asked to process sentences ‘on‐line’, choosing the agent in sentences that varied in syntactic complexity (actives, passives, subject clefts and object clefts), and in the presence or absence of a subject‐verb agreement contrast. Results revealed that accuracy and processing speeds vary with syntactic complexity in all groups, reflecting the frequency and regularity of sentence types. Developmental changes continued throughout childhood, as children became faster and more accurate at processing more complex sentence structures. Children with LI and children with FL were quite profoundly delayed, displaying profiles similar to, or more impaired than those of younger children, but there was no evidence in the FL group for a disadvantage in left‐ vs. right‐hemisphere‐damaged children. Children with LI showed one unique pattern: higher than normal costs (reflected in reaction times) in using converging information from subject‐verb agreement, in line with studies suggesting special vulnerabilities in grammatical morphology in this group. Results are discussed in terms of the Competition Model, a theory of language processing designed to account for the statistical changes in performance that are observed during development, and the probabilistic deficits in children with language impairments