Disordering behavior and helium diffusion in He+ irradiated 6H–SiC

2002 ◽  
Vol 17 (2) ◽  
pp. 271-274 ◽  
Author(s):  
W. Jiang ◽  
W. J. Weber ◽  
C. M. Wang ◽  
Y. Zhang

Single-crystal 6H–SiC wafers were irradiated at 300 K with 50 keV He+ ions to fluences ranging from 7.5 to 250 He+/nm2. Ion-channeling experiments with 2.0 MeV He+ Rutherford backscattering spectrometry were performed to determine the depth profile of Si disorder. The measured profiles are consistent with SRIM-97 simulations at and below 45 He+/nm2 but higher than the SRIM-97 prediction at both 100 and 150 He+/nm2. Cross-sectional transmission electron microscopy study indicated that the volume expansion of the material is not significant at intermediate damage levels. Results from elastic recoil detection analysis suggested that the implanted He atoms diffuse in a high-damage regime toward the surface.

1992 ◽  
Vol 263 ◽  
Author(s):  
A.E.M. de Veirman ◽  
F. Hakkens ◽  
W. Coene ◽  
F.J.A. Den Broeder

ABSTRACTThe results of a transmission electron microscopy study of Co/Au and Co/Pd multilayers are reported. Special emphasis is put on the epitaxial growth and the relaxation of the misfit strain of these high misfit systems. In bright-field cross-sectional images, periodic contrast fringes are observed at the interfaces, which are the result of Moiré interference and which allow determination of the degree of misfit relaxation at the interface. It was established that 80-85% of the misfit is relaxed. From high resolution electron microscopy images the Burgers vector of the misfit dislocations was derived, being a/2<110> lying in the (111) interface plane. The results obtained for the Co/Au and Co/Pd multilayers will be discussed in comparison with those obtained for a bilayer of Co and Au.


2003 ◽  
Vol 792 ◽  
Author(s):  
C.S. Camacho ◽  
P.F.P. Fichtner ◽  
F.C. Zawislak ◽  
G. Feldmann

ABSTRACTThe effects of film morphology (mosaic- or bamboo-like grain structures) and of He bubbles on the redistribution of Cu, as well as on the formation of Al-Cu precipitates in 200 nm thick Al/SiO2 films similar to microelectronic device interconnects, are investigated using Rutherford backscattering spectrometry, elastic recoil detection analysis and transmission electron microscopy. As-deposited and pre-annealed Al films were implanted with Cu and/or He ions forming concentration profiles located 100 nm below the surface and with peak concentrations of about 3 at.%. It is shown that grain boundaries and/or He bubbles can affect the vacancy fluxes inside the grains and reduce or even inhibit the Cu redistribution as well as the nucleation and growth of θ and θ′ Al-Cu precipitates during post-implantation annealings at temperatures from 473 to 553 K. It is also shown that mosaic-like grain structures allow the control of grain size distribution within the 25 to 1500 nm size range, thus providing an additional microstructure engineering tool to improve device reliability against electromigration failures.


1987 ◽  
Vol 107 ◽  
Author(s):  
J. Blake ◽  
J. C. Gelpey ◽  
D. M. Lee ◽  
L. Rowland ◽  
G. A. Rozgony

AbstractA cross-sectional transmission electron microscopy study has been performed on SIMOX wafers prepared using three sequential low dose (6 x 1017 cm2) oxygen implantations. After each implant the wafers were annealed using rapid thermal processing at temperatures up to 1360°C for times of 1 to 5 minutes. The TEM results show that, although low dislocation densities are obtained, oxygen precipitate dissolution is incomplete for these conditions. Therefore, longer annealing times will be required. In addition, lower increments of oxygen dose are recommended to approach dislocation-free superficial silicon layers.


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