高含氮量氧化層於氮化矽快閃記憶體元件製作與特性研究

Abstract

記憶體市場蓬勃發展，其收益日益增加，不可同日而諭，隨著製程的微縮化記憶體元件製作與特性也愈到愈來愈多的問題，最基本的是儲存資料的能力，現行的快閃記憶體是以浮動閘記憶體元件為主，而當穿隧層厚度小100Ǻ，複晶浮動閘儲存的電荷就容易從穿隧層的缺陷地方漏掉，造成原本儲存的資料遺失。 於是SONOS型態的記憶體元件被提出來，且不斷的被研究，或許是在電荷捕捉層上作改變，例如:調整電荷捕捉層的矽/氮含量者用奈米點結構來儲存電荷，有的是在穿隧氧化層上作改變，例如:用ONO結構態代替原本只有一層氧化戲的穿隧氧化層，此方法可以使漏電不易發生，也有將高介電常數材料來取代氧化矽或氮化矽，種種方法不勝枚舉。 本實驗室在穿隧氧化層上做些調整，首先用雙氧水浸泡20分鐘，在來用爐管、通氨氣來達到氮化效果，經過以上兩步驟並不會使穿碎層有足夠的厚度，所以再用乾式氧化爐管把穿隧層成長到所需的厚度，經過這些步驟高氮含量是分佈在電荷捕捉層與穿隧層介面附近，不會像用N2O直接氧化成長穿隧層的氮分佈主在矽基板與穿隧層的介面，很容易使元件在操作過程中劣化，本實驗方法可以修補穿遂層中的表面缺陷((Y. Yang and M. H. White. Solid. State Electron. Vol. 44, pp. 949, 2000.) ，進而減少儲存的電荷漏電，實驗得到的結果確實在資料儲存時間與操作次數上有非常好的改善。

The market of memory is more and more important, There are many problems in memory with technology scaling down. I gave attention in flash memory. There are two key points of flash memory are retention and endurance .At least, a flash memory product must be operated 106 cycles and the data could be identified after ten years. But the thickness of tunneling oxide is thinner with technology scaling down and the charge stored in charge storage layer will leak easily. The experiment is designed to solve the leakage of flash memory. I used oxynitride to be tunneling oxide. It was figured in 2000 by Y. Yang and M. H. White. (Y. Yang and M. H. White. Solid. State Electron. Vol. 44, pp. 949, 2000.). By this way, there would be less interface state between substrate and tunneling oxide and the charge leakage would be reduced. After measurement of my device, we can find the improvement of charge leakage.