Dry etching of Al-rich AlGaAs with silicon nitride masks for photonic crystal fabrication

作者：Zhang Xiuyu^*; Togano Yuji; Hashimura Kentaro; Morifuji Masato; Kondow Masahiko

来源：Japanese Journal of Applied Physics, 2015, 54(4): 042003.

DOI：10.7567/JJAP.54.042003

We investigate inductively coupled plasma (ICP) deep dry etching of Al0.8Ga0.2As for photonic crystal (PC) fabrication using a Cl-2/BCl3/CH4 gas mixture. On the basis of our previous report [Y. Kitabayashi et al., Jpn. J. Appl. Phys. 52, 04CG07 (2013)], we obtained a PC structure having air holes deeper than 1.5 mu m and a diameter of 120nm by adjusting the gas flow rate and increasing the process pressure. In this study, silicon nitride (SiNx) and SiO2 were both used as the mask layer. Furthermore, samples with SiNx and SiO2 masks for ICP deep dry etching were also fabricated and compared. The vertical profile of the PC structure with the SiNx mask layer displayed a rounded shape that was caused by the charge up in the mask layer. Then, a thinner mask layer was used to ease the effects of mask retardation and charge up. As a result, a PC structure with a SiNx mask layer having air holes deeper than 1.7 mu m and a diameter of 190 nm was successfully fabricated.

• 出版日期2015-4