Abstract
The regrowth of Si + -preamorphized and BF + 2 - implanted thin films on (111)Si has been studied by both plan-view and cross-sectional transmission electron microscopy. Polycrystalline Si grains were found to form in Si + -preamorphized and BF + 2 - implanted (111)Si with the original amorphous-crystalline (a-c) interface located deeper in the preamorphized Si substrate than in BF + 2 - implanted samples. Rapid thermal annealing was performed to obtain kinetic data for the formation of polycrystalline Si grains. The nucleation and growth of polycrystalline Si grains were found to occur in the amorphous phase ahead of the growing a-c interface. The incubation time for the formation of 4 nm or larger crystallites in amorphous Si at 700°C was found to be less than 30 s. The results are discussed in terms of the competition between the propagation of the a-c interface to sweep over the potential nucleation sites and random nucleation in the amorphous phase. Ramifications of the formation of polycrystalline Si grains in instances with a relatively low ion dosage and/or moderate annealing temperature are addressed.