熱電子之量子益得與GaSb/AlSb/InAs電晶體之研究

Abstract

一般的熱電子電晶體具有注入效率高,短的基極傳輸時間,以及小的基極電 阻值等特性.如果想要在電晶體中產生電子電洞對,那麼就要在空乏區加上 很大的電場來產生碰撞離子化,但是這對於元件上的應用來說並不理想.所 以我們利用銻化鋁和砷化銦這兩種化合物能帶不連續的特性,使得電晶體 可以不必在外加大電場的情形下,即可發生碰撞離子化而產生電子電洞對. 熱電子在基極產生的電洞除了供應流回射極的電流以及和在基極的電子再 結合之外,多餘的電洞會由基極流出,形成負的基極電流.我們對基極加正 向偏壓卻有電流由基極流出,這就表示該元件具有負電阻,可以應用於振盪 器或微波元件等,有很大的發展空間.在本篇論文中,我們即針對碰撞離子 化所產生的量子益得和銻化鎵/銻化鋁/砷化銦所組成的熱電子電晶體做一 番詳實的研究. Common hot electron transistors have the characteristics: high injection efficiency,short base transit time,and small base resistance.Previously,electron-hole pairs can be gene- rated by appling a large field in the depletion region to creat impact ionization. However,appling such a large volt- age is not desirable in some device application. Therefore, we use the band discontinuity of AlSb/InAs to creat impact ionization and generate electron-hole pairs. Holes generated by impact ionization can supply the current injected to the emitter and the recombination with electrons in the base. The remained holes will result in negative base current.We apply positive voltage to the base but the current flows from base , indicating negative resistance for this device. It can be used in the oscillator or microwave devices. In this thesis, we study the quantum yield by impact ionization and this GaSb/AlSb/ InAs hot electron transistor.