TEM studies of spots crystallized in amorphous films by electron beam

Abstract

Electron beam (e-beam) annealing is powerful method for local modifying and crystallization in desired modes of semiconductors and microelectronics components and is also interesting for information storing. Nevertheless, discussed in many papers mechanism of explosive crystallization of amorphous (a-Ge, a-Si) films is still not clear enough and requires new structure studies. It is more relevant for recently discovered growing of micro-crystals with strong internal lattice bending (gradient crystals) in some amorphous films. This paper reports our findings in the structure of spots crystallized in these unusual modes by TEM beam in vacuum deposited (Ge, Se, Se-Te) or prepared by pyrolysis (Fe2O3) unsupported amorphous films. Bendcontour technique was used to analyze the fields of lattice orientation for gradient crystals, including in situ crystal growth studies or videorecord analysis.Explosively crystallized spots in a-Ge, a-Si films are known to consist of 3 zones, Fig. 1. We observed the same zones for films 400-800Å thick, deposited at rates 1- 100Å/s: polycrystal central zone (O), surrounded by a fan of radially elongated single crystals (zone R) which in turn is surrounded by zone (C), formed by concentric or spiral shells (each subdivided into single-crystal subshell and polycrystal subshell).