在本篇論文中,我們利用二維元件模擬器來模擬三閘極元件內部的電位分布以及電場分布情況,並且討論三閘極元件的轉角效應,同時也使用Poisson’s Equation推導三閘極元件二維內部的電位分布情況,並且將此推導結果與我們利用二維元件模擬器得到的模擬結果做比較,再利用此結果推出模擬與推導的臨界電壓。再者,為了更了解電流的特性曲線I_D-V_G、次臨限擺幅、汲極導致能障降低等短通道效應,我們使用三維元件模擬器,分析三閘極與單閘極元件的I_D-V_G,以及單閘極與三閘極在不同通道長度下次臨限擺幅差異。 In this thesis, we design a 2-D device simulator to simulate the triple gate’s potential distribution and electron distribution , then discuss the corner effect of triple gate’s structure. We add Poisson’s Equation to analyze 2-D potential distributions and simulation, using the formula to compare with the simulation, and use the formula to obtain threshold voltage. In order to understand the characteristics I_D-V_G of device and subthreshold swing and DIBL characteristic, we add 3-D device simulator to analyze the short channel effects about triple-gate structure.