Local amorphous thin-film crystallization induced by focused electron-beam irradiation

Crystallization is induced in amorphous 80 nm films of Ge ₄₈Te₅₂ by electron irradiation to produce structures with characteristic dimensions as small as of 10-100 nm. The experiments are performed in a 200 keV field-emission scanning transmission electron microscope (TEM/STEM) that provides an electron probe about 1-2 nm in diameter (FWHM) with approximately 1 nA of current. When entire films are annealed in the absence of electron irradiation, they crystallize at approximately 450 K. Crystallization occurs under focused-probe electron irradiation when the average film temperature is as low as 300 K. The local transformation is driven by some combination of electron-beam heating and radiation-defect generation. A discussion is presented in the context of related nanocrystallization experiments driven by scanned-probe techniques for optical data storage applications.