Crystallization of growth-dominant eutectic phase-change materials

We report on initial efforts to exploit the characteristics of members of the eutectic family Ge(Sb/sub 70/Te/sub 30/)+Sb (hereafter referred to as "SGT films"). SGT films are doped with excess Sb for crystallization speed control. Ge/sub 2/Sb/sub 2.3/Te/sub 5/ (GST) films are usually nucleation-dominant in their crystallization behavior: crystallization proceeds mainly via the generation of "embryos," which if sufficiently large, form stable nucleites, which then grow from the interior and edge of amorphous-phase regions. In contrast, SGT films have low nucleation probability. As a consequence, crystallization proceeds primarily from the amorphous mark boundaries. Understanding and comparing this growth-dominant crystallization mode for various instances of the SGT films, and and comparing with nucleation-dominant GST films, is the objective of the work.