臺灣大學: 電子工程學研究所胡振國陳冠銘Chen, Kuan-MingKuan-MingChen2013-04-102018-07-102013-04-102018-07-102011http://ntur.lib.ntu.edu.tw//handle/246246/256796本論文主要在於討論金氧半結構電容—電壓特性之深空乏現象。首先建立一個模型來描述傳統上反轉區的深空乏現象。元件因邊界上的邊緣電場存在，造成了不均勻的性質，所以元件可以簡單分成邊界和內部主體看待。此模型依主導電容變化因素，對傳統上反轉區分成了三個區域，分別是內部主體和邊界均未發生深空乏(區域一)，邊界深空乏主導變化(區域二)，內部深空乏主導變化(區域三)。在區域一時，因為內部主體和邊界均未發生深空乏，所以電容維持不變。偏壓增加電容—電壓曲線進入區域二時，此時邊界相較於內部以較小偏壓達到臨界電場，所以邊界深空乏啟動，進而造成電容下降，而內部此時尚未啟動。當加更大偏壓時，電容—電壓曲線進入區域三，此時邊界空乏區深度比起在區域二時來的更深，內部也達到臨界電場，所以內部深空乏啟動。在此區域三，因為邊界的空乏區深度比起內部的空乏區深度大上很多，所以邊界空乏區的電容影響會變得沒有內部來得大，因而此區稱為內部深空乏主導。 接著把這套模型拿來分析同面積不一樣厚度及同厚度不一樣面積的金氧半結構。在同面積不一樣厚度的數據中，我們得出較厚氧化層的元件相較於較薄氧化層元件在區域三不均勻多了。因為均勻係數較小，較厚氧化層元件的電容在區域二的變化相較於區域一來的小。因為氧化層較厚，邊界深空乏的啟動電壓也會比較大。在同厚度不一樣面積數據中，透過區域三的電容密度—電壓曲線的曲率和模型的簡單計算，我們可以知道大面積的元件相對來講較均勻。接著可得知大面積元件的電容密度在區域二的變化相較於區域一來的大是因為它的均勻係數較大。In this thesis, deep depletion phenomenon in the C-V characteristics of MOS structure was investigated. In the beginning, a model was proposed to explain the deep depletion phenomenon in conventional inversion stage of C-V characteristics. Because the non-uniform characteristics results from the fringing field, devices are divided into the edge and bulk portions. And the enlarged C-V characteristic in the inversion stage is divided into three regions further, i.e., depletion-inversion region (Region 1), edge deep depletion region (Region 2), and bulk deep depletion (Region 3). In region 1, there are no deep depletion in both edge and bulk portions, so the capacitance keeps constant. As the gate bias voltage increases, the edge portion reaches its critical field which leads to the deep depletion and therefore the capacitance starts to drop in region 2. Increasing gate bias voltage further, the bulk portion reaches its critical field in region 3. In this region, the change of capacitance is mainly caused by the deep depletion in the bulk portion. Then, the model was used to explain the effects of oxide thickness on deep depletion behavior and device area on deep depletion behavior. For the device with thicker oxide but with the same pattern size, it has the smaller uniform area ratio (K) in region 3, smaller change of capacitance in region 2 with respect to region 1, and larger initiation voltage of deep depletion. For the device with larger pattern size but with the same oxide thickness, it has larger uniform area ratio in region 3 and larger change of capacitance density in region 2 with respect to region 1.1669230 bytesapplication/pdfen-US金氧半電容元件深空乏現象MOSDeep depletion phenomenonthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/256796/1/ntu-100-R98943054-1.pdf