建立電路模型探討頻率對InAs量子點蕭基二極體電性之影響

Abstract

本論文主要分成兩個部分，第一部分利用砷化鎵蕭特基二極體內含量子點成長於量子井(Dot-in-well)結構的調頻電性量測，從而推測並建構等效RC電路模型，試圖解釋與說明調頻電性量測之特殊現象。在確認等效RC電路模型之結構後，進行導納之運算， 推導出電容與電導對於頻率之關係式，並解出蕭特基電容、量子點電容等參數值，最後進行C-f與G/f-f圖之模擬。第二部分討論在變偏壓下蕭特基電容、量子點電容與電阻之情形，並利用理論計算之方式，計算出零偏壓下量子點電容與位障高度，並與等效RC電路模型之結果進行比對與討論。本論文利用空乏區尚未跨過量子層之調頻電性量測，推導出量子點電容與電阻，並使用理論計算與模擬之方式，以佐證等效RC電路模型之正確性。

There are two cases in this study. In the first case, we discuss frequency-modulated electrical properties of InAs/InGaAs dot-in-well layer embedded in a GaAs Schottky diode, and build the equivalent RC circuit model to explain this appearance. After we check the equivalent RC circuit model, we express the capacitance and conductance to frequency, and work out the capacitance of Schottky and QD, and finally simulate the C-f and G/f-f plots. In the second case, we discuss the capacitance of Schottky, capacitance of QD and resistance of QD in the different bias, and use the theoretical arithmetic to calculate the capacitance and barrier height of QD under zero bias. Then we compare the results of theoretical arithmetic with equivalent RC circuit model. To sum up, we use frequency-modulated electrical measurement for QD layer, which is located outside the depletion region, and then demonstrate the capacitance and resistance of QD with equivalent RC circuit model and theoretical arithmetic. As a result, we confirm the equivalent RC circuit model is correct.