以低壓有機金屬氣相磊晶法成長氮砷化鎵磊晶層

Abstract

在本論文中，我們使用低壓有機金屬氣相磊晶法（LP- MOCVD），在砷化鎵基板上成長出高品質的長波長材料氮砷化鎵（GaNAs）磊晶層，我們使用聯氨乙烷 (DMHy) 、三乙基鎵 (TEGa) 以及砷化三氫 (AsH3) 做為氮（N）、鎵（Ga） 以及砷（As）等的反應源。利用雙晶X射線繞射法（DCX-ray） 及二次離子質譜儀 (SIMS)來量測磊晶層厚度及氮含量。並利用吸收光譜及光激光光譜（PL）來決定能帶的變化。 實驗中我們發現在成長氮砷化鎵時成長溫度對於氮含量及磊晶品質有很大的影響。我們所成長的氮砷化鎵中氮含量可超過百分之四。一般而言，對於氮砷化鎵做適當的退火處理可以增強光激光（PL）的強度。根據吸收光譜和雙晶X光射線繞射法觀察發現在退火之後磊晶層中的氮含量並不會改變。另一方面，我們也發現在成長氮砷化鎵時加入氨氣（NH３），不會改變磊晶層中的氮含量，但是卻會增強光激光的強度。此外我們成長出高品質的氮砷化鎵/砷化鎵多層量子井結構，其中氮含量可高達百分之四，低溫量測波長可達1.113微米。

GaNAs layer with good structural quality and surface morphology has been successfully grown on a GaAs substrate using low-pressure metal organic chemical vapor deposition epitaxy. In this work, dimethylhydrazine (DMHy), triethylgallium (TEGa) and arsine (AsH3) are used for nitrogen (N), gallium (Ga) and arsenic (As) sources. The content of nitrogen within the layers was analyzed by Double Crystal X-ray diffraction (DCX-ray) and secondary-ion mass spectrometry (SIMS). The fundamental band gap energy was determined by using absorption and photoluminescence data. GaNAs layer growth temperature has a significant influence on nitrogen content and epitaxy quality. GaNAs layers with nitrogen content have grown more than 4%. Typically, post-annealing of the samples increase the GaNAs film quality and strengthen the PL intensity. According to the absorption spectrum and X-ray diffraction measurements, the nitrogen content failed to change after thermal annealing. Alternately, we also discovered that adding NH3 during GaNAs growth failed to change the nitrogen content within the films, but rather the PL intensity was increased. Furthermore, we also successfully grew high quality GaNAs MQWs, which included an N content of 4%. An 1113 nm wavelength at 8K was obtained from the PL emission of annealing a sample at 650C.