Improved stability of a phase change memory device using Ge-doped SbTe at varying ambient temperature

摘要

Ge-doped SbTe (Ge-ST) was compared with Ge_2Sb_2Te_5 (GST) for its potential use in the phase-change memory with improved stability at varying ambient temperature (T_A). Device characteristics such as RESET current, RESET resistance, and SET resistance of Ge-ST devices were found to vary significantly less with T_A than those of GST devices. From measured carrier density, mobility, and optical band gaps, these findings are interpreted to derive from a metallic nature of the crystalline Ge-ST in contrast with a semiconducting nature of the crystalline GST as well as a relatively weaker covalent bonding in amorphous Ge-ST.