先進 VLSI元件中遠程庫倫散射引起電子遷移率衰減之研究

Abstract

摘要

本文探討了在先進VLSI元件中，遠程庫倫散射引起電子遷移率衰減的情形。在高介電場效電晶體中，我們觀察到了電子遷移率衰減的情形。藉由兩種頻率電荷幫浦方法，我們顯示了電子遷移率的衰減是由高介電層內的缺隙所引起的。我們用了一個分析方程式來計算遠程庫倫散射電子遷移率，藉此來模擬遠程庫倫散射的效應。藉著對SONOS使用均勻電子寫入的方式，我們確認了電子遷移率會因遠程庫倫散射而衰減。我們的結果顯示了電子遷移率衰減會隨著面際氧化層厚度微縮而變嚴重。 為了瞭解遠程庫倫散射如何影響隨機電報訊號，我們在SONOS元件中做了隨機電報訊號的量測。藉著控制寫入窗口，在SONOS元件中我們觀察了在不同寫入窗口下的隨機電報訊號。我們觀察到在較大寫入窗口下，隨機電報訊號的振幅比較小。詳細的模型對我們仍然不是很清楚，而且需要更多的研究。

Abstract. The remote Coulomb scattering (RCS) induced mobility degradation in advanced VLSI devices is investigated. Mobility degradation in HK dielectric MOSFETs is observed. By two-frequency charge pumping method, we show that the mobility degradation is caused from the HK bulk traps. An analytical equation for RCS mobility is calculated to simulate the RCS effect. By using SONOS FN programming, we confirm that the mobility will by reduced by RCS. Our result shows that mobility will be severely limited by RCS as interfacial oxide thickness (IOT) scaling.

Try to know that how RCS effect affects random telegraph signal (RTS) noise, the RTS noise is characterized in SONOS flash memories. By controlling program window, the RTS noise at different program window is observed in SONOS flash memories. The amplitude of RTS at larger program window is smaller. The detailed model is still puzzling and needed more investigation.