Solid phase epitaxial regrowth of buried amorphous silicon layers obtained by ion irradiation

In this work, using Rutherford backscattering of 4He+ ions combined with channeling and cross-section transmission electron microscopy, we studied the solid phase epitaxial recrystallization (SPER) of buried layers of amorphous silicon (a-Si), obtained by Ar+, Ge+ or 29Si+ ion bombardment. The SPER process of buried a-Si layers is characterized by the different motion velocities of the external and internal amorphous-crystalline interfaces. At least two factors affect the motion of the a-c interfaces: the existence of implanted impurities and the difference in concentration of defects in the regions adjacent to the a-c interfaces. Both factors are the consequence of an asymmetry in the distribution of impurity and defects with respect to the initial position of a-c interfaces. A model of the recrystallization process, taking into consideration the influence of vacancies and interstitial defects on the motion of the a-c interfaces has been proposed. (orig.)