用于悬浮纳米结构制作的氢氟酸气相刻蚀研究

Study on HF Vapor-Phase Etching for Suspended Nano Structure Fabrication

针对纳米悬浮结构的制作,对不同温度和不同气相条件下的氢氟酸(HF)气相刻蚀进行了研究。利用自制的研究装置,使用HF/水混合气体和HF/乙醇混合气体分别进行了HF对PECVD SiO2的气相刻蚀实验,同时测量了不同衬底温度下刻蚀速率的变化。研究结果表明,在常温常压下,HF/乙醇混合气体气相刻蚀速率约为7.6 nm/s,而HF/水混合气体气相刻蚀速率约为11.5 nm/s。在衬底温度分别为35,40和50℃时,HF/水混合气体的气相刻蚀速率分别为10.25,7.95和5.18 nm/s。利用HF气相腐蚀进行SiO2牺牲层释放,得到了悬浮的纳米梁结构,梁与衬底的间距为400 nm。

HF vapor-phase etching was studied under different temperatures and different conditions for fabrication of suspended nano structure. Using self-made HF vapor-phase etching equipment and using HF/ H2O vapor and HF/CH3CH2OH vapor as working gas, PECVD SiO2 sacrificial layer etchings are performed. The HF/H2O vapor etching rates are measured respect to different substrate temperatures. Experimental results show that the etching rates of HF/H2O vapor and HF/CH3CH2OH are 11.5 and 7.6 nm/s at room temperature and atmosphere pressure. The HF/H2O vapor etching rate decreased with wafer temperature increasing and are 10.25, 7.95 and 5.18 nm/s at the temperature of 35, 40 and 50 ℃, respectively. Nano suspended structure with 400 nm gap between structure and wafer substrate is fabricated by the HF vapor phase etching method.