Construction for enhancing reliability of phase-change memory storage unit and manufacturing method thereof

Abstract

The invention relates to a structure which can improve the reliability of a memory cell of a phase change memory and a preparation method thereof. The structure and the method are characterized in that a thin layer of cushion material is added between a nanometer heating electrode and a pillar-shaped phase change material of the same diameter to improve adhesiveness and interface match between the phase change material and the heating electrode, simultaneously, electrical match between the phase change material and the heating electrode can be improved, and an ohmic contact can be formed. In addition, a thin layer of thermal resistance material is added between the phase change material and the top electrode so as to improve thermal balance in the process of device erasing and writing, and reduce heat dissipation of the top electrode and energy consumption of the device. The structure of the memory cell prevents diffusion between the phase change material and the heating electrode and the interfacial failure in the process of repeated erasing and writing, and improves the reliability of the device. The heating electrode, the cushion material and a phase change region are limited to the same dielectric hole to form a self-aligned pillar-shaped structure, and an insulating layer does not need to be prepared around the phase change material, thereby reducing the technology process.

Description

technical field [0001] The invention relates to a structure for improving the reliability of a storage unit of a phase-change memory and a manufacturing method thereof, belonging to the field of nanometer devices and preparation techniques in microelectronics. Background technique [0002] At present, there is no ideal high-capacity low-cost of dynamic random access memory (DRAM), high speed of static random access memory (SRAM), non-volatile data of flash memory (FLASH), and simultaneous Memory with high reliability, low operating voltage, and low power consumption, and these characteristics are exactly the storage technologies required by the new generation of consumer electronics industry, computer industry and other fields. Phase-change memory (PCRAM) has the advantages of small memory cell size, non-volatility, long cycle life, good stability, low power consumption, and strong embeddability, especially in terms of device feature size reduction. It is believed that in t...

AI Technical Summary

Problems solved by technology

The key problems of this structure are mainly: (1) The mechanical and electrical matching between the columnar heating electrode and the phase change material. Usually the phase change material is relatively soft, and the hardness of the heating electrode material is relatively large, so that the heating electrode is on the phase change material. Cracks are prone to occur; in addition, the electrical contact between the heating electrode material and the phase change material is usually not a normal ohmic type, there is a Schottky barrier, and the contact resistance is too large. If the contact resistance reaches 10 3 It is difficult to distinguish the resistance value of the phase change material in the polycrystalline state above the ohm

(2) The heat dissipation of the top electrode is too large, resulting in a large power consumption of the device during the erasing process

(3) The reversible phase change region in the phase change material will expand during repeated erasing and writing, which will affect the performance and reliability of the device

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