The microstructure of high-energy (0.5–6.0 MEV) As-ion implanted Si and rapid thermal annnealed (RTA'd) Si has been studied by transmission electron microscopy (TEM). The implantations formed buried amorphous layers that recrystallized during RTA at different temperatures and became either single crystal or polycrystalline depending on their implation energy and fluence. At energies > 2.5 MeV and fluences < 1015 cm−2, recrystallization occurred below 400°C and regowth was single crystal. At an energy of 6 MeV and fluence of 5 × 1015 cm−2 recrystallization occurred above 600°C and regrowth was polycrystalline. When the implantation energy and fluence were reduced to 0.5 MeV and 2 × 1014 cm−2, respectively, recrystallization occurred above 600°C and regrowth was polycrystalline. The above results are explained by both the formation mechanisms of amorphous Si resulting from ion implantation and the structural order of a-Si.
With conventional transmission electron microscopy (TEM), dynamic events are pieced together with micrographs from a multitude of specimens annealed at different temperatures over the range of interest. Real-time imaging of dynamic events in the microscope provides the ability to view the entire anneal temperature span with one specimen. As reported by Parker, cross-sectional TEM can be used to observe real-time kinetic phenomena in silicon. Fiore and Herring later reported a new technique for preparing cross-sectional specimens that are annealable to temperatures as high as 1300°C. Both of these recently developed techniques have been used to observe the amorphous-to-crystalline phase transformation and defect network formation in high-energy ion implanted silicon.Cross-sectional specimens were annealed in a Philips CM 12 transmission electron microscope equipped with a heating holder. The specimens were prepared from [111 ]-oriented silicon wafers implanted with 5.5 Mev Ga ions at a dose of lO15 cm-2. Using a ramp-up temperature from ∽30°C to 1000°C over a 5-minute period, the dynamic events were recorded on 3/4-inch video tape from a TEM TV system.
We describe a technique for preparing transmission electron microscope (TEM) cross-sectional specimens for observation during in situ annealing to high temperatures. The process utilizes a ceramic adhesive that is stable to a temperature of 1650°C. The technique, which was successfully used to observe the recrystallization of amorphized silicon, is being applied to high-energy ion-implanted silicon in an attempt to better understand the amorphous-to-crystalline phase transformation and defect formation mechanisms resulting from thermal processing.
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