以MOCVD成長GaSb,AlGaSb與量測GaSb/AlGaSb/GaSb之電流傳輸

Abstract

本文主要是在常壓下使用有機金屬化學氣相沉積法,研究砷化鎵晶片上成 長銻化鎵(GaSb)與銻化鋁鎵(AlGaSb)之薄膜,以及單屏障銻化鎵/銻化鋁 鎵/銻化鎵結構之電流傳輸特性。在GaSb的成長中,成長溫度的改變影響較 大,其次是五三比的調變。此外較高之TMSb流量,會在較高之溫度得到好的 GaSb薄膜品質。成長之銻化鋁鎵均為p型,600℃之成長品質會優於680℃。 Al攙入GaSb晶體的成長中,會使得移動率遞減得很快,與載子濃度遞增得很 快。在GaSb/AlXGa1-XSb/GaSb結構的電流-電壓傳輸方面,Al含量在0.3以 上,室溫下即有整流的特性。此特性顯示GaSb/AlGaSb之間具有能帶不連續 性的存在。我們使用簡單之熱激理論來分析此電流傳輸機制。 We used the metal organic chemical vapor deposition epitaxial in atmospheric pressure to study the growth of GaSb and AlGaSb on GaAs substrates and the current transport properties in GaSb/ AlXGa1-XSb/GaSb structures. In GaSb growth,the growth temperature is more strongly influence the growth condition than the V/III ratio.The TMSb Flow rate is also found to influence the GaSb growth condition. Under higher TMSb flow rate ，high quality GaSb layers can be grown at higher substrate temperation. The grown of AlXGa1-XSb is p-type. The quality of AlXGa1-XSb grown at 600℃ is better than that at 680℃. The mobility was reduced rapidly and the carrier concentration increase rapidly when Al was incorpoeated into GaSb crystal growth. In GaSb/AlXGa1-XSb/GaSb structures，the room- temperature current voltage characteristic shows a rectified feature when Al composition X is higher than 0.3. This rectified feature shows a valence-band distinuity in GaSb/ AlGaSb interface. The thermionic emission theorem was used to analyze the current transport mechanism.