Dry etched mesas for buried heterostructure InGaAsP/InP lasers using electron cyclotron resonance Cl2/CH4/H2/Ar discharges

Abstract

High-density, magnetically enhanced discharges of Cl2/CH4/H2/Ar were shown to provide rapid dry etching of InGaAsP/InP laser structures for sample temperatures of greater than 130 ‡C. The etch rates were ~1 Μm min−1, and they were more than an order of magnitude faster than for conventional CH4/H2/Ar etching. Smooth, anisotropic mesa sidewalls were obtained when the direct-current (d.c.) self-bias was kept low (−80 V). The etched surfaces were suitable for epitaxial regrowth of current-blocking layers by either organo-metallic-vapour-phase epitaxy or metal-organic molecular-beam epitaxy. In the former technique, addition of CCl4 to the growth chemistry was helpful in preventing deposition of polycrystalline InP on the dielectric mask.