Device Characteristics of a Ge-doped SbTe alloy for High-speed Phase-change Random Access Memory

Abstract

We investigated the influence of phase-change materials on the device performance for low-power and high-speed phase-change random access memory (PCRAM). The Ge-doped SbTe (Ge-ST) alloy was used as a phase-change material and was compared with the conventional Ge2Sb2Te5 (GST225) alloy. An as-deposited Ge-ST film grown by using chemical vapor deposition had an amorphous phase which showed the superior gap-fill capability compared to as-deposited crystalline GST225. The crystallization time for the set operation was decreased to 80 ns, and the reset current reduced to 0.16 mA when Ge-ST was introduced in sub-40 nm a PCRAM. In addition, the Ge-ST alloy showed a good data retention property of 10 years guaranteed at 100 ◦C. These results will enable us to realize low-power and high-speed PCRAM devices beyond the sub-40 nm design rule.