傳統(0001)面的低壓SiC MOSFETs元件因為SiC/SiO2介面的高Dit，通道遷移率受到了限制，為了改善這個問題，本實驗提出了利用(112̅0)面側壁作為部分通道的tri-gate結構，並且分別使用NO、N2O進行氧化後退火降低Dit並比較他們帶來的影響。
本論文使用N型MOS capacitors、平面型MOSFETs、tri-gate MOSFETs來評估元件的特性以及氧化後退火的比較。跟N2O製程比起來NO製程(0001)面在距離傳導帶0.1 eV處的Dit值下降了約40 %，而且sub-threshold slope(S.S.)降低了20 %左右。Tri-gate結構的S.S.相比於平面結構也降低了約22 %，汲極飽和電流也大約是平面結構的兩倍。最後是初步的討論元件閘極氧化層可靠度，在適當的Vg ,max下， NO製程的tri-gate MOSFET不僅有著最佳的電流特性，而且不論是PBTI、NBTI都有著最小的ΔVTH，然而，在動態導通電阻的穩定性有觀察到一些問題。

Due to the high Dit at the SiC/SiO2 interface, the channel mobility of conventional (0001) face low-voltage SiC MOSFETs is limited. In order to improve this issue, this work proposes a tri-gate structure which include the (112̅0) face sidewall as part of the channel. In addition, NO and N2O are used for post-oxidation annealing to reduce the Dit and their effects are compared.
N-type MOS capacitors, planar MOSFETs, and tri-gate MOSFETs are used to evaluate the characteristics of devices and compare them with different post-oxidation annealing. Compared to the N2O process, the Dit¬ value for (0001) face of the NO process at E-EC=0.1 eV is reduced by about 40%, and the sub-threshold slope (S.S.) is reduced by about 20 %. Compared to the planar structure, the S.S. of tri-gate structure is also reduced by about 22 %, and the drain saturation current is about twice as large as the planar structure. Finally, the preliminary reliability of the gate oxide is discussed. Tri-gate MOSFET with NO process not only has the best current characteristics, but also has the smallest ΔVTH for both PBTI and NBTI under a reasonable Vg,max. However, some dynamic Ron issue is observed.

中文摘要 i
Abstract ii
目錄 iii
圖目錄 vi
表目錄 ix
第一章 序論 1
1.1 前言 1
1.1.1 碳化矽材料特性介紹 1
1.1.2 碳化矽與氧化層介面特性 3
1.2 文獻回顧 4
1.2.1 碳化矽與氧化層介面特性之改善 4
1.2.2 碳化矽(112̅0)面與通道遷移率 5
1.2.3 垂直型功率Tri-gate MOSFET 7
1.3 研究動機 8
1.4 論文大綱 9
第二章 元件設計與實驗介紹 10
2.1 元件介紹 10
2.1.1 垂直型電容器(MOS capacitors) 10
2.1.2 平面型金氧半場效電晶體(Planar MOSFETs) 11
2.1.3 三閘極型金氧半場效電晶體(Tri-gate MOSFETs) 12
2.2 NO及N2O介面氮化 13
2.3 元件基本電性量測 15
2.3.1 電容-電壓特性量測(C-V) 15
2.3.2 C-V量測與介面能態密度 17
2.3.3 MOSFETs元件順向導通特性 20
2.4 元件可靠度測試 22
2.4.1 SiC元件閘極氧化層可靠度 22
2.4.2 BTI對元件可靠度的影響 22
2.4.3 電荷汲引技術(Charge pumping) 23
第三章 結構及退火氣體對元件的影響 26
3.1 垂直型電容器量測之結果與分析 26
3.1.1 不同退火製程對氧化層影響 26
3.1.2 SiC/SiO2介面能態密度(Dit)結果討論 27
3.2 多閘極型與水平型金氧半場效電晶體比較及討論 30
3.2.1 順向導通電流 30
3.2.2 溫度效應對順向導通特性影響 36
3.2.3 汲極崩潰電壓 39
第四章 元件可靠度 40
4.1 BTI的結果分析 40
4.2 電荷汲取技術 44
4.2.1 電荷汲取電流 44
4.2.2 次臨界遲滯(Subthreshold hysteresis) 45
4.2.3 量測溫度與電荷汲取技術 50
4.3 動態導通電阻穩定性(Dynamic Ron) 52
第五章 結論及未來展望 55
參考文獻 57

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