111 research outputs found
The Fermi level effect in III-V intermixing: The final nail in the coffin?
Copyright 1997 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Journal of Applied Physics 81, 2179 (1997) and may be found at
Interdiffusion: A probe of vacancy diffusion in III-V materials
Copyright 1997 by the American Physical Society. Article is available at
Clustering of vacancy defects in high-purity semi-insulating SiC
Positron lifetime spectroscopy was used to study native vacancy defects in
semi-insulating silicon carbide. The material is shown to contain (i) vacancy
clusters consisting of 4--5 missing atoms and (ii) Si vacancy related
negatively charged defects. The total open volume bound to the clusters
anticorrelates with the electrical resistivity both in as-grown and annealed
material. Our results suggest that Si vacancy related complexes compensate
electrically the as-grown material, but migrate to increase the size of the
clusters during annealing, leading to loss of resistivity.Comment: 8 pages, 5 figure
Positron lifetime measurements on neutron‐irradiated InP crystals
Neutron‐irradiated InP single crystals have been investigated by positron‐lifetime measurements. The samples were irradiated with thermal neutrons at different fluences yielding concentrations for Sn‐transmuted atoms between 2×1015 and 2×1018 cm−3. The lifetime spectra have been analyzed into one exponential decay component. The mean lifetimes show a monotonous increase with the irradiation dose from 246 to 282 ps. The increase in the lifetime has been associated to a defect containing an Indium vacancy. Thermal annealing at 550 °C reduces the lifetime until values closed to those obtained for the as‐grown and conventionally doped InP [email protected] ; [email protected]
Grown-in vacancy-type defects in poly- and single crystalline silicon investigated by positron annihilation
Positron annihilation was used to characterize vacancy-type defects in two
types of polycrystalline Si grown at temperatures above ~800 °C
by chemical vapour deposition. The majority of vacancies (80%) consisted
of monovacancies, and their thermal stability indicated them to be trapped
at grain boundaries or at dislocations. Annealing above 500 °C caused a
significant reduction in the monovacancy concentration, and an increase in
divacancy concentration. Divacancies started to anneal above 1200 °C.
Measurements between 8 and 293 K indicated that vacancies were neutral
before as well as after annealing at 1380 °C. Fz-grown Si from one of
these materials contained vacancy clusters with an average size of six to
ten vacancies which persisted to 1380 °C. The cluster concentration
corresponded to a monovacancy concentration of 1015 to 1016 cm−3, which is at least one order of magnitude larger than estimates
based on voids [R. Falster, V.V. Voronko, F. Quast, Phys. Status Solidi B
222, 219 (2000)]
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