Low-power phase-change memory cell based on a doped GeTe/InP heterostructure: a first-principles study.

An access-transistor-free (0T1R) structure has been reported to have great advantages in reducing the area of the phase-change memory cell, but leakage current has limited its application in large-scale arrays. In this study, a GeTe/InP heterostructure is proposed as the integration of a selector and phase-change cell in a 0T1R structure. The effect of establishing a GeTe/InP heterostructure is explored based on first-principles study, and the performance is further optimized by doping. The results show that, compared with GeTe, the band gap value of the GeTe/InP heterostructure decreases, and the space charge region forms at the interface, which effectively suppresses the leakage current of the 0T1R structure. In addition, to further improve the performance of GeTe/InP, group III-V elements are used as substitutional dopants at the P site. We find that when N and B dopants are used, the electrical conductivity of GeTe/InP and the charge transfer between interfaces are enhanced. The current–voltage characteristic curves show that the establishment of the GeTe/InP heterostructure and doping significantly improved the nonlinear coefficient of the phase-change memory cell, which can better suppress the leakage current in the 0T1R structure. [ABSTRACT FROM AUTHOR]