The crystallization of Ge:Al amorphous films was studied by time resolve TEM intensively in previous years and reported[1]. These studies included the geometry and the dynamics of Al-amorphous interface with time resolution of 40 milliseconds by conventional bright-field (BF) and dark-field (DF) TEM imaging of films of 50 nm thickness and by conventional high resolution (HR) TEM of films of 25nm thickness. The propagation of the Al interface is diffusion controlled, i.e. the velocity is temperature dependent [1]. The Al-amorphous interface was found to be rough with a fractal dimension of 1.2 for the projected image [2]. However, the quantitative analysis of the interface propagation indicates a long range interaction in the Al-amorphous phase interface [3]. These interactions were attributed to existence of ramified clusters of Al in the Ge:Al amorphous phase [4].

Here we will report on quantitative measurements that were obtained with 5 nm thick films heated locally by the electron beam resulting in the modification of the surface. The quantitative measurements will be based on observations that include aberration corrected HRTEM with low time resolution (1 sec) and by conventional HRTEM with high time resolution (few milliseconds). The later will be used also for evaluating the stability of the interface toward its 3D construction. 

References:

1. Y. Lereah, E. Grunbaum and G. Deutscher, Physical Review A 44 8316 (1991)

2. Y. Lereah, J.M. Penisson and A. Bourret, Applied Physics Letters 60 1682 (1992)

3. Y. Lereah, A. Gladckikh, S. Buldyrev and H.E. Stanley, Physical Review Letters 83, 784 (1999)

4. Y. Lereah, S. Buldyrev and H.E. Stanley, Materials Science Forum Vols. 294-296 (1999) p. 525-528

Figures:

Fig. 1 A 80 kV aberration corrected HRTEM image of an Al-amorphous interface. The atomic scale roughness indicates that the 5nm thick film should be regarded as 3D object.

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