Formation of Double-Channel Mesa Structure for GaSb-BASED MID-Infrared Laser

Abstract

ABSTRACTSemiconducting antimonide compounds have received increasing attention as the alternative materials for mid-infrared photonic devices, with a variety of applications such as remote sensing, pollution monitoring, and molecular spectroscopy. For many, if not all these devices it is necessary to pattern antimonide films into mesa or line structures. While plasma etching techniques have played an increasing role in producing such features, little was reported until now on dry etching of GaSb- and AlSb-containing alloys. In this paper we present the results of our recent work towards the development of the technology for GaSb-based ridge wave-guide laser emitting at 2–2.3 μm at RT. Specifically, we discuss the fabrication of double-channel mesa structure in AlxGai1−xAsySb1−y/GaSb (x=0.2–0.5) heterostructure materials by RIE technique. The effects of gas and material composition, rf power, pressure and temperature on etching characteristics were studied with special attention paid to surface quality, etching rate and etching profile, which are crucial for obtaining a single mode waveguide. CCI2F2/H2 and CCI4/H2 process chemistries were investigated which shows the latter to provide vertical sidewalls and residue free etch surfaces at controllable etch rates.