Three-dimensional stacked phase change memory and preparation method thereof

Abstract

The invention discloses a three-dimensional stacked phase change memory and a preparation method thereof. The preparation method comprises a step of preparing first horizontal electrodes with spacingfrom each other on a substrate, a step of preparing first strip-shaped phase change layers with gaps in the centers in areas corresponding to the spacing of the first horizontal electrodes, a step ofpreparing first gate tubes between the gaps of the first strip-shaped phase change layers, a step of preparing a first insulating layer, a step of preparing second horizontal electrodes at the same vertical positions on the first insulating layer, a step of preparing second strip-shaped phase change layers, a step of preparing second gate tubes, a step of preparing horizontal insulating holes in the spacing of the horizontal electrodes, and a step of preparing a vertical electrode between adjacent insulating holes and then forming a multi-layer stacked phase change memory with a vertical structure. According to the invention, the overall process design of the key preparation method, the shape setting of each detail structure and the like are improved, and the problems of complicated multi-layer stacking steps, difficult process realization and the miniaturization of a unit size of the three-dimensional stacked phase change memory in the process preparation are solved.

Description

technical field [0001] The invention belongs to the technical field of microelectronic devices and memories, and more specifically relates to a three-dimensional stacked phase-change memory and a preparation method thereof. Background technique [0002] As a new type of memory that is most likely to develop into one of the mainstream memories in the future, in order to meet the demand for high-capacity storage in the era of big data, phase change memory is gradually developing into three dimensions, forming a multi-layer stacked three-dimensional phase change memory. [0003] At present, the three-dimensional stacked phase change memory is simply stacked vertically upwards based on the horizontal electrode intersection array structure. Although the structure is simple, as the number of stacked layers increases, the process steps are cumbersome, and the surface unevenness is intensified, which brings Reliability issues; in addition, the feature size of the memory cell is limi...

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Problems solved by technology

[0004] In view of the above defects or improvement needs of the prior art, the purpose of the present invention is to provide a three-dimensional stacked phase change memory and its preparation method, wherein the overall flow process design of its key preparation method, the shape setting of each detailed structure, etc. Improvement, compared with the prior art, it can effectively solve the problems of complex multi-layer stacking steps in the process preparation of three-dimensional stacked phase change memory devices, difficulty in process realization, and unit size reduction. The present invention adopts a vertical electrode structure to establish a three-dimensional phase change memory In the change memory array, the feature size of the phase change unit is determined by the thickness of the film (for example, the thickness of the phase change layer can be as low as 2nm, which breaks through the limitation of photolithography process), and the phase change unit in the three-dimensional stacked phase change memory formed is located on the horizontal electrode Spatial overlapping area with the vertical electrode, the preparation process can be effectively simplified

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