GaSb基VCSEL刻蚀工艺研究

摘要

2 μm~5 μm GaSb-based VCSEL is an ideal light source for atmospheric detection. However, the immaturity of its fabrication technology seriously hinders its development. The undercutting effect is the outstanding etch problem in its fabrication. In this paper, Etching characteristics of GaSb is investigated in detail by use of phosphoric acid plus tartaric acid solution. In order to compare them, we chose concentration ratio of H3PO4:H2O2:C4H6O6:H2O as 1 mL: 1 mL: 0.3 g: 10 mL, 1 mL: 1 mL: 0.6 g: 10 mL, and 1 mL: 1 mL: 1 g: 10 mL, respectively. The testing results from step profiler and scanning electron microscopy (SEM) were compared and analyzed. Etched GaSb in the solution with a concentration ratio of H3PO4:H2O2:C4H6O6:H2O=1:1:0.6:10 shows very good morphology. Undercutting effect was eliminated and a vertical side wall was obtained with no lateral etching. Etching rate is 0.62 μm/min. The perfect etch behavior of GaSb provides a good technical support for laser preparation.%2μm~5μm波段GaSb基VCSEL对大气检测技术有着重要的应用,但制备技术的不成熟严重制约着GaSb基VCSEL的发展.刻蚀工艺中出现的下切效应就是器件制备中存在的突出问题.针对上述问题,选择三种不同成分的磷酸系刻蚀液进行了对比性刻蚀实验,并通过台阶仪、扫描电子显微镜(SEM)测试观察了刻蚀速率和表面形貌.实验分析表明,浓度配比为1 mL:1 mL:0.6 g:10 mL的H3PO4:H2O2:C4H6O6:H2O刻蚀液具有良好的腐蚀效果,消除了以往腐蚀过程中出现的下切效应,且垂直形貌好,未出现钻蚀现象,晶片表面平整且光滑,且保持稳定的刻蚀速率0.62μm/min,为激光器制备提供了良好的前期实验基础.