電子可擦拭可儲存唯讀記憶體直流及高頻儲存/擦拭之暫態

Abstract

在直流儲存/擦拭中,直接加上一個負電壓於源/基極,於是把一寄生於電子 可擦拭可儲存唯讀記憶體之電子可儲存唯讀記憶體導通.通道式熱電子產 生並加入F-N穿透式電流, 一起參與儲存動作.在高頻波動式儲存/擦拭方 式,直接在元件之閘極加上正(負)高頻高壓之波群,於是元件儲存(擦拭)後 之電位均顯著地加強.這是由於高頻波動,窄波引起深層空乏狀態下而激發 另一額外的熱電子所導致.經由實驗證明此種儲存/擦拭方式確實比傳統之 儲存/ 擦拭使用較小之電壓. 於是本論文之研究成果可以應用在未來的電 子可擦拭可儲存唯讀記憶體. In this thesis, Two writing/erasing methods using dc voltage or high-frequencypulses for FLOTOX EEOROM cells are presented and analyzed. They have also beensuccessfully verified by experimental devices.In the DC writing/erasing, an extra dc negative source and substrate voltageis added to turn on the parasiticEPROM device in the FLOTOX EEPROM. Thus thechannel hot- electron injection current in addition to the F-N tunnelingcurrent can be generated in writing the FLOTOX EEPROM devices. Thus thewriting efficiency can be increased.In the high-frequency pulse writing and erasing in the FLOTOX EEPROM devices,a positive (negative) voltage pulse train is applied to the gate.Thewriting (erasing) operation becomes much more efficient so that the written(erased) efficiency is enhanced by the extra hot-carrier injection under thedeep depletion condition (DDC) which is caused by high-frequency gate pulses, short pulse base-level duration, and leaky oxide. It has been verified fromthe measurement data that the pulse writing and erasing operations can beperformed with a lower voltage than the conventional dc operations. Thus theycan be applied in future EEPROM.