- 作者: 高耀堂; 王世維; 郭雙發
- 作者服務機構: 交通大學電子研究所
- 中文摘要: 本研究比較了幾種可以使用在離子植入電腦模擬中的核子及電子阻擋模式。對核子阻擋而言,吾人發現,莫里耳電位最重,通用電位最輕,而Kr-C電位則介於其間。對非局部電子阻擋而言,以LSS模式最簡單,若選擇適當的修正參數值,可以得到不錯的結果。ZBL模式則依實驗值而設,必須使用與實驗結果相吻合的八參數模式。ABS模式在許多離子與靶的組合中,它通常具有最大的電子能量損失,只適用於中低能量之範圍。 為了建立一個較為物理的電子阻擋模式,吾人採用Klein,Park及Tasch三人所提議的局部能量損失模式,使用Runge-Kutta方法計算離子在靶中的路徑,使用cubic-spline匹配法求出不同位置的靶原子之電子電荷密度。而與局部電子濃度相依的電子能量損失,則依照ABS模式的方法來計算。假使吾人在蒙地卡羅模擬中的每一次碰撞都如此計算的話,這將是一個非常耗費時間的工作,為了節省計算時間,在模擬過程中,吾人事先算出不同離子能量及入衝參數下的電子能量損失,再以除差(divided difference)內插法求出在此二維數據下各個碰撞的電子能量損失。此外,在此研究所得到的電子阻檔也與其他局部能量損失模式(如OR及XLL)相比較。
- 英文摘要: In this study, we compare various nuclear and electronic stopping power models which can be usedin the computer simulation of ion implantations. For nuclear stopping, we find that the Moliere potentialis the heaviest interatomic potential, the universal potential is the lightest one and the Kr-C potential isthe intermediate one. For nonlocal electronic stopping, the LSS (Lindhard, Scharff, and Schiott) modelis the simplest model, and good results can be obtained by properly adjusting a correction factor. TheZBL (Ziegler, Biersack, and Littmark) model is the most elaborate nonlocal model, but eight parametershave to be used to fit to the experimental results. The ABS (Azziz, Brannon, and Srinivasan) model hasthe largest stopping power for various ion-target combinations and is usable only at low or intermediateenergy. To establish a more physical model of electronic stopping based on local energy loss as first proposedby Klein, Park, and Tasch (KPT), the Runge-Kutta method is used to compute the trajectory of an ionin collision with a target atom, and the cubic spline fitting method is used to interpolate the electroniccharge density of a target atom at different positions. Electron concentration dependent energy loss isevaluated according to the ABS model. This is a time consuming job if we do all of these calculationsfor every collision in the Monte Carlo simulation. To reduce the computer time, the electronic energyloss of an ion in a target as a function of impact parameter and incident energy is precalculated, and adivided difference method has been developed to interpolate the two dimensional data in the simulationprocess. The electronic stopping obtained in this work is compared with other local energy loss modelssuch as OR (Oen and Robinson) and XLL (Xia, Lau, and Lennard).
- 中文關鍵字: process simulation; ion implantation; physical model
- 英文關鍵字: --