Superlattice phase change thin film with low density change, phase change memory and preparation method thereof

Abstract

The invention discloses a superlattice phase change film with low density change, a phase change memory and a preparation method. The superlattice phase change film comprises a first phase change layer and a second phase change layer which are alternately stacked to form a periodic structure ; During the crystallization process, the first phase change layer has a conventional positive density change, while the second phase change layer has an abnormal negative density change, so its density during the crystallization process is abnormally reduced and the volume increases, It can be used to counteract the volume reduction phenomenon of the first phase change layer during the crystallization process; the superlattice film formed by alternately stacking conventional phase change materials and materials with negative density changes can reduce the phase change memory material during the phase change process. The volume change of the phase change memory material can reduce the voids caused by the repeated increase and decrease of the volume of the phase change memory material during the cycle of erasing and writing; The stability of cyclic erasing and writing of the phase change memory device is significantly increased, and the service life of the device is improved.

Description

Technical field [0001] The present invention belongs to the technical field of microelectronic devices and memory, and more particularly, to a density variation of a superlattice phase-change film, a phase change memory and its preparation method. Background technique [0002] Since the phase change memory material which can achieve rapid reversible change between the crystalline state (low resistance state) and an amorphous (high resistance state) by applying an electrical or optical pulses much attention as a high impedance transformation process SET resistance state is referred to the process, which is the reverse process is called RESET process. Technology-based storage phase change material is believed to be a strong contender for one of the next-generation storage technology. [0003] Two-state phase change material having a different mass density, in general, since the crystalline state of ordering a higher atomic density, smaller. Due to its amorphous disordered atomic di...

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Problems solved by technology

At present, the two types of phase change layer materials in superlattice phase change materials also have the characteristics of large changes in the two-state density, resulting in "voids" in the process of repeated erasing and writing. Therefore, superlattice phase change materials still have multiple cycles of erasure. The problem of device failure after writing

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