Fabrication of InGaAsP/InP ridge waveguide lasers with dry etched facets using chemically assisted ion beam etching and a simple photoresist mask

Abstract

Dry etched facets remain a very attractive task in the semiconductor laser diode fabrication, as they can potentially lead to on-wafer device fabrication including preliminary testing, allowing thus a substantial cost reduction. Chemically assisted ion beam etching (CAIBE) technique is commonly applied to this aim, as it allows for vertical sidewall etching combined with high etch rates. However, while on the GaAlAs/GaAs basis some quite convincing results were achieved (Unger et al., 1993), this seems not to be the case for the InGaAsP/InP laser devices to the same extent. Published results were obtained either at low temperature etching (5/spl deg/C) with IBr/sub 3/ as a chemical component (Eisele et al., 1996), or at higher temperatures (250-300/spl deg/C) with Cl/sub 2/ using multilayer masks or thick (700 nm) SiO/sub 2/ (Youtsey et al., 1994; Dzioba et al., 1993; Tsang et al., 1999). In this paper we present, to our knowledge for the first time, results on ridge waveguide (RW) lasers with dry etched laser facets using a simple photoresist mask, without any additional treatment after the lithographic exposure. We demonstrate that the fabricated devices show identical characteristics to those of lasers with cleaved facets.