Crystallization Kinetics of Amorphous Ga-Sb Films Extended for Phase-Change Memory

Performance of phase-change materials based on Ga-Te-Sb was found getting better with decreasing Te content in our earlier studies. We concerned much properties of Te-free, Sb-rich binary Ga-Sb, which has been known to possess extremely fast crystallization behavior. Non-isothermal and isothermal crystallization kinetics of amorphous Sb-rich Ga-Sb films were explored by temperature dependent electrical resistance measurements. The crystallization temperature (183 to 261 °C) increases with decreasing Sb content (91 to 77 at%). The activation energy and rate-factor vary with Sb contents and reach the maximum at Ga₁₉Sb₈₁. The kinetic exponent is smaller than 1.5 at Sb <85 at% denoting that the mechanism is one-dimensional crystal-growth from nuclei. The temperature corresponding to 10-year data-retention, evaluated from films, is 180 °C (Ga₁₉Sb₈₁) and 137 °C (Ga₁₃Sb₈₇), respectively. We verified memory performance using test-devices made of Ga₁₆Sb₈₄ working at voltages with 100 ns pulse-width.