新型單層多晶矽非揮發性記憶體之研究

The Study of The Novel NVM Device

洪志學(Chih-Hsueh Hung)

指導教授 ： 鄭湘原

中原大學/工學院/電子工程研究所/碩士(2003年)

https://doi.org/10.6840/cycu200300619

摘要

中文摘要

半導體記憶體在現今的發展中依照其記憶特性可分為揮發性記憶體及非揮發性記憶體。揮發性記憶體主要以動態隨機存取記憶體 (Dynamic Random Access Memory，DRAM)及靜態隨機存取記憶體 (Static Random Access Memory，SRAM) 。近年來隨著可攜式產品(如筆記型電腦、數位相機等)的普及，非揮發性記憶體在半導體記憶元件的發展與研究上，其所扮演的角色是愈來愈重要。非揮發性記憶體至1967年來以發展三十多年，非揮發性記憶體的技術也在逐年進步。從早期的唯讀記憶體(Read-Only-Memory，ROM)、可程式唯讀記憶體(Programmable-Read-Only-Memory，PROM)，到可抹除程式化唯讀記憶體(Erasable- Programmable-Read-Only-Memory，EPROM)、電性可抹除程化唯讀記憶體(Electrically Erasable Programmable Read Only Memory，EEPROM)，以至目前最熱門的快閃記憶體(Flash Memory)，非揮發性記憶體在其結構及儲存之材料上隨技術之演進亦有所變化。近來以氮化矽為電荷儲存材料之記憶體元件受到相當的注意。
本論文是以新型單層多晶矽非揮發性記憶體為研究主題，由於此新型單層多晶矽記憶體元件具有多位元儲存特性，及與其它非揮發性記憶體相比具有更高的CMOS製程整合性，於是此新型單層多晶矽記憶體元件可大大地降低生產成本。
本論文首先就簡介此新型單層多晶矽記憶體元件的操作原理，包括利用通道熱電子做為寫入機制和利用熱電洞的注入做為抹除機制，及利用順向讀取和反向讀取機制在單一元件中判別兩儲存位元。實驗方面，利用新型單層多晶矽記憶體元件與標準MOSFET元件及不同條件之新型單層多晶矽記憶體元件比較，從實驗結果中可以驗證新型單層多晶矽記憶體元件在適當條件下具有較大的寫入/抹除邏輯位差。因此新型單層多晶矽記憶體元件適合做為記憶元件。從實驗結果中也可初步得知此新型單層多晶矽記憶體元件具有良好的可靠度。接著利用TSUPREM4製程模擬軟體及MEDICI電性模擬軟體針對此新型記憶體元件做製程及電性上模擬。藉由模擬觀察利用通道熱電子注入之寫入機制的區域性儲存特性(localized trapping)，並利用電性模擬之結果與實際實驗結果做比較，並針對兩者之差異上做探討。

關鍵字

非揮發性記憶體 ； 快閃記憶體

並列摘要

Abstract

Solid-State memory devices can be divided into two major categories, one is the “Volatile” memory and the other is called “Non-Volatile” Memory. NVMs have been manufactured over thirty years, and it has been becoming more and more important in the semiconductor industry because of being applied in portable and mobile applications for data storage. First, the history of the Non-Volatile Memory (NVM), the concept of the NVM and the classifications of NVMs are introduced. Recently, charge trapping memory devices (such as Silicon-Oxide-Nitride-Oxide-Silicon) become the most popular because of its complete compatibility with existing advanced CMOS technology. Under sufficiently high electric field, several physical phenomena including “Hot Carrier Effect” (HCE), “Band-to-Band Tunneling” (BTBT), and “Fowler-Nordheim” (FN) Tunneling are observed. These mechanisms under high field effects can be exactly used as the program and erase operations of NVMs and have been discussed in chap two.
In this thesis, the novel NVM device is compared with standard n-MOSFET and the novel NVM device with different conditions. From the experimental results, the novel NVM device is promising for two-bit NVM applications and the novel NVM device have good data retention behavior. TSUPREM4 and MEDICI simulation tools are used to simulating the novel NVM device. Finally, the simulation and experimental results are compared and discussed.

並列關鍵字

flash memory ； NVM

參考文獻

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