Investigation on Ultra-high Density and High Speed Non-volatile Phase Change Random Access Memory (PCRAM) by Material Engineering

Abstract

AbstractIn this paper, ultra-high memory density and high speed non-volatile phase change random access memory (PCRAM) was investigated by material engineering. The melting point, crystallization point and activation energy of crystallization of the Bismuth (Bi) doped Germanium-Antimony-Tellurium (GeSbTe) compound was measured using differential scanning calorimetry (DSC) and compared to other GeSbTe ternary compounds. It was observed that the melting temperature of Bi-doped GeSbTe was lower than that of GeSbTe. On the other hand, its activation barrier was found to be reduced, which in turn increased the speed of crystallization of Bi-doped GeSbTe. Bi-doped GeSbTe was then used as a phase change material in the fabrication of PCRAM devices. The properties of PCRAM fabricated using this material were then compared to those using GeSbTe, with emphasis on the programming current required. The results obtained revealed that lower programming current of up to 40% has been achieved for PCRAM with Bi-doped GeSbTe compared to those with other GeSbTe compounds. Bi-doped GeSbTe also has low RESET current and fast speed of crystallization with scaling, making it a suitable material for high speed, ultra-high density PCRAM fabrication in the future.