Electron beam induced crystallization of sputter deposited amorphous alumina thin films

Crystallization of amorphous alumina (Al2O3) in a thin film capacitor structure was induced by the electron beam of a transmission electron microscope (TEM). The crystallization was initially observed while collecting selected area diffraction (SAD) patterns after 2 min of beam exposure at an accelerating voltage of 200 keV and a beam current density of 13.0 A/cm2. After 16 min of beam exposure, distinct ring patterns associated with crystal growth were evident in the SAD pattern. Bright field and dark field TEM images confirmed that crystallization occurred, with crystals growing up to ~50 nm in diameter.

► Thin film capacitors examined by TEM. ► Amorphous Al2O3 crystallized under 200 keV electron beam at beam current of 13 A/m2. ► Al2O3 crystals reached ~50 nm in diameter after 16 min of beam exposure. ► Crystal growth indicates thermal crystallization process.