低溫鈍化技術於多功能薄膜之研究與應用

Abstract

在此論文裡，我們研究了介電常數材料在超臨界二氧化碳流體混合水的熱處理下其電性的改變。首先，在室溫下，利用電子束蒸渡系統成長極薄的氧化矽薄膜，厚度約為7奈米，為了取代傳統的高溫退火製程，能在未來於玻璃基本上運用。使用了溫度約150°C超臨界流體混合水的技術，為了驗證超臨界流體混合水能有效的使水分子進入到氧化矽，進而減少薄膜的缺陷密度，我們經由紅外線光譜儀、熱脫附常壓游離質譜儀與X射線光電子能譜來做材料分析，結果均顯示於氧化矽薄膜內氧的含量增加，而厚度為7奈米氧化矽薄膜在閘極電壓3伏特的操作下，其單位面積漏電流約為2×10-7 A/cm2，並且得到較高的崩潰電壓，崩潰電壓約為6伏特，傳導機制亦由原本未經過處理的量子穿隧效應轉換為熱放射效應，以上主要的原因是由於氧化矽薄膜的缺陷密度減少。 除此之外，我們發現在超臨界二氧化碳流體混合水處理過後的薄膜擁有非揮發性電阻式記憶體的特性。並且量測了其儲存的時間，可靠度，提出了相關的物理模型去解釋其儲存的成因。藉由薄膜內部處理過後剩餘的缺陷，施加足夠的偏壓下，使其缺陷內部電子發生局部穿隧的情形，進而改變能帶。產生了電阻的改變，達到記憶體的特性。 由這些結果均顯示，藉由超臨界流體混合水的技術，能減少薄膜的缺陷密度。並且也能在低溫下製造出記憶體。可預期的，若超臨界流體的特殊特性整合在介電常數材料、薄膜電晶體、太陽能電池與記憶體製程上，將具有其優勢。

In this study, supercritical fluids (SCF) technology is employed originally to effectively improve the properties of low-temperature-deposited silicon oxide dielectric films. In this work, 7 nm ultra-thin Silicon Oxide (SiOx) films are fabricated by e-gun method at room temperature, and replacing the conventional high temperature annealing with supercritical fluids treatment at 150 °C. The supercritical fluids act a transporter to deliver H2O molecule into the SiOx films for repairing defect states. After this proposed process, the absorption peaks of Si-O bonding apparently raise and the quantity of oxygen in SiOx film increases from FTIR and TDS measurement, individually. The leakage current density of 7 nm SiOx film is cut down to 2×10-7 A/cm2 at |Vg| = 3 V, and the conduction mechanism is transferred from quantum tunneling to thermal emission because of the significantly reducing the defects in the SiOx film. Moreover, the higher breakdown voltage is obtained, reaching |Vg| = 6 V. Additionally, the RRAM characteristics was found in SiOx film treated by supercritical fluid,and retention,endurance were measured.when less trap was in treated film,the bias was applied enough on film,that made tunning effect happened inside.The resistence changed was by binding energy .