Crystallization Kinetics of Amorphous Ga-Sb films Extended for Phase-change Memory

Performance of phase-change RAM 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 crystallization kinetics of amorphous Sh-rich GaxSb100-x. films were investigated by using in-situ electrical resistance - temperature measurements. The activation energy (E-o) and rate factor (K-o) were evaluated from the heating rate dependency of the peak crystallization temperature using the Kissinger's method. The kinetic exponent (n) was deduced from the differential resistance - temperature curves during crystallization using the Ozama's method. The crystallization temperature (T-2 = 261 to 182 degrees C) decreased with decreasing Ga content (Ga 23 to 9 at%). The activation energy (E-o = 8.34 to 2.31 eV) and rate factor (K-o = 4.66 x 10(82) to 2.33 x 10(26) min(-1)) inconsistently changed at different Ga content and reached a maximum value at composition 19 at% Ga. The n value is smaller than 1.5 as Ga > 15 at%, denoting the mechanism of one-dimensional crystal growth from nuclei. GuSb films with 16 similar to 18% Ga were found to he the optimal for use in phase-change memory.