本篇論文中，我們探討萃取Si材料的電子和電洞撞擊游離係數，藉由加入載子碰撞游離模型於二維元件模型內，來模擬半導體元件內部載子發生雪崩崩潰之現象。首先，我們探討 pn 接面二極體，藉此元件來探討不同濃度下載子的傳輸現象，並且進行一系列的 pn 二極體模擬。再來介紹兩種不同的撞擊游離萃取方法，第一種為分離法，分別求出電子或電洞的撞擊游離係數,先設電洞撞擊游離係數已知或不重要,藉由 pn 所量測出來的 I-V 圖對應到四邊圖形的四個猜值來搜尋電子撞擊係數的斜率及截距兩個未知變數，同理可求電洞撞擊係數的兩個未知變數。第二種為耦合法，由四位元的十六種排列組合對應到 pn 量測出來的I-V圖一起求出電子和電洞撞擊係數的四個未知變數。以上兩種萃取方法適用在所有電場下，比逐步在一固定電場下的電子和電洞撞擊係數萃取來的更準確又有效率。This thesis reports the extraction of impact ionization for the silicon material. We design a 2-D device simulator which includes the impact ionization model to simulate the avalanche breakdown. At first, we use p-n diode to discuss the impact generation current with different doping concentration in p-n diode. Secondly, we introduce two methods for impact ionization extraction. One is the decoupled method. This method is used to find the intercept and slope for the electron impact ionization parameters if the hole impact ionization parameters are given. We obtain four I-V curves from 4 guessed parameters, and compare the 4 I-V curves with the measured I-V curve. The 4 guessed parameters forms a square in the 2D searching space. By moving the square and comparing the I-V curves, the intercept and the slope parameters can be obtained. Similarly, the hole impact ionization parameters can be obtained. The other method is the coupled method. The coupled method is used to find electron and hole impact ionization parameters simultaneously with 4 unknown variables. Compared with the extraction method in one fixed electric field, this method is more efficient and accurate because the intercept and the slope are valid for a wide range of electric filed.
