利用晶圓接合與雷射剝離技術製作氮化鎵面射型雷射

Abstract

由於氮化鎵材料的發光元件可廣泛應用於照明燈、光儲存和光通訊等領域，因此過去幾十年來氮化鎵相關的材料吸引了學術界和業界的目光，在近幾年的研究表現上具有非常卓越的突破。 我們藉由雷射剝離與晶圓接合技術製作不同結構的面射型雷射，在完成以後，我們以脈衝波的方式對元件的光電特性進行量測，包括 LIV特性及近場的實驗結果，在改良結構下其10 μm與12 μm孔徑大小的元件均成功達成雷射操作，其閾值電流密度分別為57.30 kA/cm2與57.47 kA/cm2。 在近場光形中我們可以發現具有雷射操作的區域只有一小塊，原因與缺陷息息相關，在未來若是以其他低缺陷的磊晶製作元件的話，勢必良率以及發光區域將會大幅改善。ITO的吸收以及n-GaN表面的不平整將使得損耗變大，也使得閾值電流上升，故未來將以改善ITO厚度以及研磨製程以讓閾值電流下降。

Solid state electronics have attracted considerable attentions over the past decades, owing to their wide variety of applications. In particular, GaN-based devices, which can be applied in back lighting, ambient lighting, display, optical storage, optical communication, and so on, have been widely investigated by both academia and industry. Recently, several remarkable breakthroughs in device performance were reported. Laser lift-off and wafer bonding techniques were adopted in order to fabricate different types of vertical-cavity surface-emitting lasers. The laser characteristics such as L-I-V curve, near field images were measured by electroluminescence system under pulse condition. Lasing action were achieved in optimized devices with 10 micrometers and 12 micrometers aperture, and the threshold current density were 57.30 kA/cm2 and 57.47 kA/cm2 respectively. Non-uniform light emitting inside the aperture can be attributed to surface defects. We believe that, by using low defect density epi-wafer in fabrication, the defect-free rate and emission uniformity can be improved in the future. In addition, lower threshold current can be achieved by reducing the thickness of ITO layer and further polishing on n-GaN side to obtain smooth surface.