电荷俘获存储器阻挡层研究进展

Research Progress of Blocking Layers in Charge Trapping Memories

随着非挥发性存储器(NVM)存储单元的特征尺寸进入20 nm节点,使用单层SiO2作为阻挡层的传统电荷俘获存储器结构性能上逐渐受到限制。基于阻挡层在存储器栅堆栈中的作用与基本要求,首先,指出单层SiO2作为阻挡层存在的主要问题,然后对高介电常数材料作为阻挡层时,其禁带宽度、介电常数、内部的缺陷密度以及退火工艺等方面对存储特性的影响进行了分析,同时对近年来研究较多的阻挡层能带工程进行了详细介绍,如SiO2和Al2O3的复合阻挡层结构、多层高介电常数材料的阻挡层结构等。最后,对目前研究进展中存在的问题以及未来的研究方向和趋势进行了总结和展望。

With the non-volatile memory（NVM） technology enters 20 nm-node,conventional charge trapping memories with the SiO2 blocking layer confront severe performance limitation.Based on the function and basic requirements of the blocking layers in the charge trapping me-mory grid stack,the main problems of the single SiO2 blocking layer are pointed out firstly.And then,the impact of the band gap,dielectric constant,internal defect density and annealing process of the high-k blocking layer as the blocking layer on the memory characteristics is analyzed.Moreover,the energy band engineering of blocking layers researched much recently,such as SiO2/Al2O3 stacked structure and the multi-layer high-k material blocking layer structure,is discussed in detail.Finally,the problems of latest research progress as well as the direction and tendence for future research are given.