Solid phase crystallization of thin films of Si prepared by plasma-enhanced chemical vapor deposition

Abstract

Solid phase crystallization of thin films of undoped amorphous Si prepared by plasma enhanced chemical vapor deposition has been studied by transmission electron microscopy (TEM). From the TEM images, the thermodynamic parameters for the amorphous and crystalline phases were extracted. These parameters were compared with those previously reported for evaporated, chemical vapor deposited, and self-implanted amorphous Si. We conclude that the thermodynamic parameters are very similar for different amorphous Si films, although the initial structure of the films is comparatively different from one to another. To explain this, the existence of an intermediate amorphous state is assumed and discussed.

Anomalous crystallization of hydrogenated amorphous silicon during fast heating ramps

“…Although the standard kinetic parameters used to plot the solid line in Fig. 2 are consistent with experiments done on a variety of materials (hydrogenated LPCVD 6 and PECVD 8 and dehydrogenated a-Si 4,5 ), very few experiments have tested their validity at T > 700°C. To our knowledge, only Spinella et al 4 have measured the kinetic parameters above this temperature (at 740 and 780°C), and they agree with the standard kinetics.…”

“…Figure 2 is the conventional Kissinger plot for crystallization at the constant heating rates 14 of our measurements (symbols). In addition, from the values of the kinetic parameters that are broadly accepted [4][5][6]8 corrresponding to homogeneous nucleation, the solid line predicts the expected behavior for a three-dimensional (3D) crystallization process. Below 25 K/min, the agreement is excellent for a very large range of heating rates (see the whole set of measurements in Ref.…”

“…2 The kinetics of this process follows the nucleation and growth steps with rate constants characterized by transmission electron microscopy. [3][4][5][6] The relative values of nucleation and growth rates determine the final grain size that can be controlled through the crystallization temperature or by ion irradiation during crystallization. 4 The temperature range in the published results seldom extends above 700°C because of the difficulty in reaching the isothermal conditions without any incipient crystallization taking place during the heating ramp.…”

Atomistic modeling of ion implantation technologies in silicon

“…The recombination of such a bond defect would be equivalent to the generation of a crystal embryo in the amorphous phase. The activation energy for crystal nucleation in amorphous Si has been experimentally determined to be 5 eV [17]. Consequently, the higher the number of surrounding bond defects, the higher the activation energy for bond defect recombination.…”

Molecular Dynamics Studies of the Ion Beam Induced Crystallization in Silicon

“…However, from thermodynamic considerations a few of them will become large enough for growth to be favoured. The nucleahon and growth of small crystal clusters are thermally activated processes that have been described theokticalry [2] and experimentally in silicon [3].…”