Multilevel resistance state tuned by change in crystallization mode of superlattice-like Sb/Si3N4 films

Abstract

Phase change materials (PCMs) have been attracting increasing interest in computer bionics and artificial intelligence neuron systems. However, the influence of interface between Si3N4 and PCMs on phase chang behavior is still unclear. In this paper, phase change performance and crystallization behavior of homogeneous Sb film are adjusted by changing the thickness of the Si3N4 film and the iteration period. Sb film covered by Si3N4 has better thermal stability, better data retention, and higher crystallization rate due to that the stable Si3N4 can reduce the long-range order and inhibit the nano-size growth of Sb crystal grains. The low element diffusion between Sb and Si3N4 is favorable to stabilize the nano-interface and significantly improve the resistance drift. The resistance polymorphism including high, intermediate, and low resistance states can be obtained by annealing at different temperatures. The ability to achieve such a multilevel resistance state is ascribed to the nucleation-dominated crystallization mode.