半导体存储器可分为两类,一类具有截断电源写入的存储信息就消失的特性,另一类具有电源切断后存储信息仍不消失的特性。一般前者称为易消性存储器,后者称为非易消性存储器。易消性存储器的典型代表是广泛采用的双极型和MOS型的随机存储器(RAM),它具有在1毫秒以下的时间里写入,读出和消失信息的特点。但有切断电源存储信息就不能保持的缺点。为此,近年来对通电时写入存储信息并且即使在切断电源后存储信息仍能保持很长时间的非易消性存储器的研究十分活跃。 Semiconductor memory can be divided into two categories, one with the truncated power supply to write the information stored on the disappeared, the other has the power cut off the storage information is still not disappearing characteristics. The former generally known as consumer memory, the latter known as non-volatile memory. Typical examples of volatile memory are the widely used bipolar and MOS types of random access memory (RAM), which have the ability to write, read, and disappear information in under 1 millisecond. However, there is a shortcoming that power supply information can not be stored. In recent years, research into writing nonvolatile memory that stores information at power-on and that can retain a long time even after power is cut off has been very active.