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Formation of the anomalous cellular structure in (100) GaSb with Sn ion-implantation at a low temperature is investigated by cross-sectional scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. A fine structure consisting of many cells was formed on GaSb surface implanted by 60 keV Sn. The cell diameter and the thickness of the walls partitioning the cells were about 50 and 10 nm, respectively, which are almost constant in the range of the ion dose 4.0×1014–8.9×1014 ions/cm2. The depth of the cells increased linearly with increasing ion dose, from 100 nm in the sample implanted with a dose of 4.0×1014 ions/cm2 to 220 nm in that implanted with a dose of 8.9×1014 ions/cm2. From the experimental results, it is concluded that the development of the cellular structure originates in formation of the voids. An improved defect formation mechanism based on movement of the implantation-induced point defects is discussed.

The amorphization and recrystallization of tin‐ion‐implanted gallium arsenide were studied by cross‐sectional transmission electron microscopy. Amorphization occurred in the sample implanted at a dose of 1014 ions/cm2. The interface between the amorphous region and the crystalline matrix is not flat. The amorphous region recrystallizes epitaxially with microtwin formation at 673 K. The amorphous‐crystalline interface in the sample implanted at a dose of 1016 ions/cm2 is flat. In the deep region of this sample a solid‐phase epitaxial growth without microtwin formation is observed after annealing at 673 K. These structural changes were compared with the nuclear energy loss (damage energy) distribution simulated by the trim code. It is concluded that the amorphization of the sample implanted at a dose of 1014 ions/cm2 is induced by the accumulation of damage energy; on the other hand, the amorphization of the sample implanted at a dose of 1016 ions/cm2 cannot be explained only by this process. The contributi...

Hydrothermal ZnO wafers implanted at room temperature with 60 keV Sn+ ions are examined by means of photoluminescence (PL), atomic force spectroscopy (AFM), and X-ray diffractometry techniques. The PL intensity significantly decreases in the wafers implanted to doses of 4.1 × 1013 ions/cm2 and higher. The AFM measurements indicate that surface roughness variation is not the cause of the significant decrease in PL intensity. Furthermore, the PL deep level (DL) band peak blueshifts after illuminating the implanted samples with the He-Cd laser 325 nm line; meanwhile, the DL band intensity first increases and then decreases with illumination time. These abnormal behaviors of the DL band are discussed.

The annealing effect of neutron irradiation has been observed for radiation damage in self-ion implanted silicon. Si samples implanted with (0.5–2)×1015Si∕cm2 were neutron irradiated at 400°C with the total number of displacements of 8.8×10−3dpa. A heavily disordered (not amorphized) sample clearly showed damage annealing enhanced by the neutron irradiation. The annealing efficiency (the ratio of annealed defects to atomic displacements) was calculated to be 1.3 defects/displacement. This annealing efficiency was compared with the results of previous ion beam annealing studies.

Cross‐sectional views of iron ion‐implanted gallium arsenide to doses of 4×1014 cm−2 and 1×1015 cm−2 were observed by transmission electron microscopy before and after annealing at 673 K. Microtwins were formed below the surface by implantation of 4×1014 ions cm−2. In the sample implanted to the dose of 1×1015 cm−2 , the region below the surface was amorphized and a thin microtwin layer was observed between the amorphous layer and the crystalline matrix. The electron diffraction pattern and the high‐resolution multibeam lattice image showed that the structure of the microtwin is an atomic stacking of ABCA‘CB‘ABC along the 〈111〉 direction. In both samples, the microtwin layer transformed to the amorphous structure by annealing at 673 K for 30 min. It is suggested that the behavior in gallium arsenide implanted with iron, which is much different from that implanted with the other ion species, may be attributed to the coordination number of the covalent bonding iron.