Platinum has been diffused at 600, 700 and 800°C into n-type epitaxial silicon samples with and without prior 2 MeV electron irradiation at doses of 1×10
14–1×10
17 cm
−2. Without prior electron ...irradiation, diffusion at 700 and 800°C for 30 min resulted in the presence of a single deep level in the DLTS (Deep Level Transient Spectroscopy) spectrum, which is attributed to the platinum acceptor level at 0.23 eV below the conduction band edge. At lower diffusion temperatures no deep level was detected. However, after prior electron irradiation and subsequent in-diffusion at 600°C this platinum level is again present in the DLTS spectrum. Depth profiling shows, that the platinum concentration increases with electron dose. Its value after in-diffusion without prior irradiation at 750°C is comparable to the one after in-diffusion at 600°C following a dose of 1×10
17 cm
−2. A tentative explanation of this enhanced diffusion is proposed and the influence of the irradiation induced vacancies and silicon self-interstitials is discussed.
Transmission electron microscopy has been used to study the bubbles and the extended defect formation in crystalline Si implanted with helium at a dose of 10
17
cm
−2
at 1.6 MeV and annealed at ...800°C, as a function of the annealing time of 16.7-1020 min. Below the bubble layer located near the mean projected range, Frank dislocation loops are observed in addition to long rod-like {113} defects. During the initial annealing stage only Frank loops bound to bubbles are present. Whereas the bubble morphology does not change greatly during longer annealing times, we observe a strong evolution of extended defects located behind the band of bubbles. Indeed, after a 30min annealing, Frank loops and {113} defects resulting from the precipitation of Si interstitials are observed. Then the dissolution of {113} defects takes place and only Frank loops remain. The Frank loops are homogeneously distributed up to 500 nm below the bubble layer and are of equal size. After a 1020 min anneal, no more extended defects are observed behind the buried layer. These results are discussed and compared with those obtained after keV implantation.
MBE-growth conditions of mixed As/P and P-based heterostructures are studied. The objective is to improve their optical and structural characteristics. Growths were performed on multiwafer production ...system. Successive campaign data and maintenance procedure are presented
Si(100) samples of n-type have been implanted with 5.6 MeV 28Si3+ at room temperature using a dose of 1x108 cm-2. Thereafter the samples were annealed in nitrogen ambient for 30 min at temperatures ...from 400DGC to 800DGC using steps of 50DGC. Deep level transient spectroscopy (DLTS) was used for sample analysis. Deep levels, not previously reported in the literature, are observed to arise, evolve, and to vanish again in the described temperature interval, while above 650DGC only two defects levels remain. Depth profiles of these levels show, that the maximum concentrations of the defects are located deeper than the projected range, as is characteristic for secondary implantation defects. Their possible identities are discussed.
Myospherulosis of the maxillary sinus Godey, B; Martinez, E; Le Gall, F ...
Annales d'oto-laryngologie et de chirurgie cervico-faciale
120, Številka:
6
Journal Article
Recenzirano
We present a case of a myospherulosis, describe the underlying cause and discuss ways of preventing its development.
A 35-year-old man presented myospherulosis of the maxillary sinus caused by an ...antibiotic ointment placed in the sinus three years earlier during a Caldwell Luc procedure. The patient underwent a second Calwell Luc procedure. Outcome was uneventful and no recurrence was noted.
Histological examination should be ordered at reoperation and petroleum-based ointments and packings should be avoided in sinus surgery.
Si(1
0
0) samples of n-type have been implanted with 5.6 MeV
28Si
3+ at room temperature using a dose of 1
×
10
8 cm
−2. Thereafter the samples were annealed in nitrogen ambient for 30 min at ...temperatures from 400°C to 800°C using steps of 50°C. Deep level transient spectroscopy (DLTS) was used for sample analysis. Deep levels, not previously reported in the literature, are observed to arise, evolve, and to vanish again in the described temperature interval, while above 650°C only two defects levels remain. Depth profiles of these levels show, that the maximum concentrations of the defects are located deeper than the projected range, as is characteristic for secondary implantation defects. Their possible identities are discussed.
The authors report a case of laryngeal ulceration due to cytomegalovirus occurring in a 60-year-old man one month after heart transplant. The recipient was initially CMV seronegative and the donor ...positive. No preventive treatment was administered. One month after the transplantation, search for CMV in blood and urine became positive and a seroconversion occurred. Laryngeal biopsy showed an inflammatory reaction with cells containing atypical inclusions and positivities with anti-CMV antibody. Usual intranuclear eosinophilic inclusions of classic CMV infection were absent. The authors stress the unusual site of the lesions in this primo-infection and the atypical aspect of the inclusions. Such atypical inclusions which have already been reported in immunosuppressed people make the diagnosis more difficult.
