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本文提出一种新型的电编程序和可变唯读存储器。文中叙述了对于重迭栅雪崩注入型MOS场效应晶体管(SAMOS)中的电子注入、俘获和发射的研究结果,介绍了以这种新结构制成的全译码256位唯读存储器,还研究了俘获电荷的保持与漏出机构。“写”的过程指的是电子注入到浮置栅上并被俘获在上面,浮置栅埋置在栅氧化物中并完全绝缘。SAMOS晶体管的写入时间为20微秒,这个时间比FAMOS晶体管的写入时间(20毫秒)要短得多。存储内容的清除可以采用光学上的光电发射或电学上的场致发射的方法。用光学方法清除记忆时,写入和清除循环能够无限重复;采用电学方法清除时,重复次数为10次以上。俘获电荷的漏出可能是由于栅氧化物中存在的正空间电荷引起福勒-诺尔德哈姆(Fowler-Nordheim)隧道发射的缘故。浮置栅中俘获电荷的半衰期时间在150℃之下估计可达100年以上。与普通硅栅晶体管相比,制造SAMOS仅需要增加一个成本不高的工序。
This paper presents a new type of programming and variable read-only memory. In this paper, the research results of electron injection, trapping and emission in a cascaded gate avalanche-injected MOS field-effect transistor (SAMOS) are described. The full decoding 256-bit ROM with this new structure is also introduced Trapping the charge holding and leakage mechanism. The process of “writing” refers to the electron injection onto the floating gate and its capture, the floating gate buried in the gate oxide and completely insulated. The SAMOS transistor has a write time of 20 microseconds, which is much shorter than the FAMOS transistor write time (20 milliseconds). The removal of stored content may take the form of optical photoemission or electrical field emission. When optically clearing a memory, writing and erasing cycles can be repeated indefinitely; when electrically cleared, the number of repetitions is 10 or more. Leakage of trapped charges may be due to the Fowler-Nordheim tunnel emission due to the positive space charge present in the gate oxide. The half-life of trapped charges in the floating gate is estimated at up to 100 years at 150 ° C. Compared with the ordinary silicon gate transistor, SAMOS only need to add a less expensive process.