Fast switching and low drift of TiSbTe thin films for phase change memory applications

Abstract

As the non-volatile storage medium of the next generation, phase-change random-access memory (PCRAM) has characteristics such as high density, low cost and a wide range of market applications. However, the write speed of GST-based PCRAM falls short of the current DRAM memories and its applications domain expansion is limited. In this article, TiSbTe (TST) shows good performance both in high speed and low drift due to its fast crystallization rate and titanium-centered stable octahedral structure. The promising properties of this new material are illustrated in a 4 Mb chip for embedded applications and tested at wafer level, and the results show that the crystallization speed of TST is improved by 80% and a smaller resistance drift is achieved, with the drift exponent coefficient of highest resistance level being as low as is 0.02, compared with GeSbTe (GST).