日本东芝公司为了能使新一代的高密度NAND型存储器实用化，已研制成能大幅度缩小存储器单元面积的器件技术。NAND型存储器由于存储单元的结构简单，作为适合于大容量的半导体特别引人注目。为了使记忆媒体实用化，占芯片面积大部分的存储器单元面积缩小和低价格的技术是必要的 Toshiba Corporation in order to make a new generation of high-density NAND-type memory practical, has been developed to significantly reduce the memory cell area device technology. The NAND type memory is particularly attractive as a semiconductor suitable for a large capacity due to the simple structure of the memory cell. In order to make the practical use of the storage media, it is necessary to reduce the area of ​​memory cells and reduce the cost of most of the chip area