Design, Fabrication, and Micro-Reflectance Measurement of a GaAs/AlAs-Oxide Antireflection Film

We have designed and fabricated a double-layer antireflection (AR) film by selective oxidation of an epitaxially grown GaAs/AlAs heterostructure. The method presented in this work has the advantage that it is much simpler in processing than the conventional AR coating method. Furthermore, the fabrication steps for the AR films are fully compatible with the standard monolithic semiconductor device processing technology so that the films can be easily and economically manufactured. The reflectance of the fabricated AR films was measured using a micro-reflectance measurement setup based on a 2×1 fiber coupler, which offered a spatial resolution on the order of the fiber core diameter. The measured reflectance showed a minimum value as low as 0.0033 at a wavelength of 1064 nm, and the 1 % reflectance bandwidth was measured to be 23 nm.