在氧化物限制型垂直腔面发射激光器制备中,刻蚀GaAs/AlGaAs时因异质型材料常出现选择性内蚀现象,这会直接影响后续的氧化工艺及电极钝化的效果。针对因选择性内蚀而出现的“镂空”现象,对湿法刻蚀工艺和干法刻蚀工艺进行详细研究,研究结果表明通过调整刻蚀液体积配比和感应耦合等离子体(ICP)刻蚀下电极射频功率可有效消除“镂空”现象。湿法刻蚀中,当刻蚀液H3PO4-H2O2-H2O各物质体积配比为1∶1∶10时,得到了陡直度较好且光滑的侧壁。ICP干法刻蚀时,通过改变下电极RF功率可调整腔室内的化学刻蚀和物理刻蚀的动态平衡,在下电极射频功率为100 W时,“镂空”现象基本消失,且侧壁陡直度大于80°。

In the preparation of oxide confinement vertical-cavity surface-emitting lasers, selective internal corrosion often occurs when GaAs/AlGaAs is etched, which directly affects the subsequent oxidation process and electrode passivation. To address this problem, the wet and the dry etching processes are thoroughly investigated in this study. Results show that the hollows caused by selective internal corrosion can be effectively eliminated by adjusting the volume ratio of the etching solution and bottom electrode radio frequency (RF) power of the inductively coupled plasma (ICP) etching. We obtain good steepness and smoothness in the wet etching process when the volume ratio of the H3PO4-H2O2-H2O solution is 1:1∶10. In the ICP dry etching process, the dynamic balance of the chemical and physical etching in the chamber is adjusted by changing the RF power of the bottom electrode; the hollow phenomenon is hardly observed, and the sidewall steepness is greater than 80° at a power of 100 W.