首次采用椭偏光谱仪检测ＨＦ缓冲溶液（ＢＨＦ）处理的Ｓｉ（１１１）表面在空气中的化学稳定性．研究表明：随着Ｓｉ暴露在空气中时间的增长，Ｓｉ的赝介电常数虚部ε２的Ｅ２临界点峰值随之下降，而Ｅ１临界点峰值却随之上升；在ｐＨ＝５．３的ＢＨＦ中腐蚀，再经去离子水漂洗后，可得到较稳定的Ｓｉ（１１１）表面，在空气中一小时之内基本不氧化． The chemical stability of Si (111) surface treated with HF buffer solution (BHF) in air for the first time was investigated by ellipsometry. The results show that as the time of Si exposure to air increases, the peak value of E2 of the imaginary part ε2 of Si decreases, while the peak of the critical point of E1 increases. At pH = 5.3, In the corrosion, and then deionized water rinse, you can get a more stable Si (111) surface in the air within an hour basically no oxidation.