Epitaxial recrystallization of nano-sized amorphous layers, phase nucleation and growth in 4H-SiC


Epitaxial recrystallization of nano-sized amorphous layers, phase nucleation and growth in 4H-SiC

Gao, F.; Zhang, Y.; Posselt, M.; Devanathan, R.; Weber, W. J.

Two nano-sized amorphous layers embedded in perfect crystals have been modeled to study the amorphous-to-crystalline (a-c) transition in the temperature range from 1000 to 2000 K in 4H-SiC by means of classical molecular dynamics methods. The results show that the epitaxial recrystallization of amorphous layers with a-c interface along the c-axis is much faster than that along the basal plane, which suggest the anisotropies in the different activation energies for recrystallization. The recovery of bond defects and the rearrangement of atoms at the interface are important processes driving the epitaxial recrystallization of the amorphous layers. The nano-sized amorphous layer with the a-c interface oriented along the c-axis can be fully recrystallized at all temperatures considered. However, it is observed that second ordered phases, crystalline 3C-SiC, nucleate and grow during the recrystallization process inside the amorphous layer with the a-c interface along the basal plane, and these new phases are stable for long simulation times. Based on a model developed in the previous annealing simulations of 3C-SiC, the range of activation energies are determined to be about 0.35 eV to 2.4 eV, which suggests that the recrystallization consists of multiple recovery processes, rather than a single process proposed previously. The present results are discussed and compared with the annealing simulations of 3C-SiC and experimental observations. The simulation results are in good agreement with previous experimental results in SiC, and thus, provide atomic-level insights into the interpretation of experimentally observed phenomena.

Keywords: computer simulation; recrystallization; SiC

  • Invited lecture (Conferences)
    MRS 2005 Fall Meeting, 27.11.-01.12.2005, Boston, MA, USA

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Publ.-Id: 7884