Low-temperature CAIBE processes for InP-based optoelectronics

Abstract

We have developed Cl/sub 2//Ar and IBr/sub 3//Ar chemically-assisted ion-beam etching (CAIBE) processes, which allow high-quality etching of InP-based materials such as laser mirrors and gratings at low substrate temperatures (/spl ap/0/spl deg/C). Etch rates of 400-750 /spl Aring//min and excellent surface morphologies at substrate temperatures between -5/spl deg/C and +10/spl deg/C with both Cl/sub 2//Ar and IBr/sub 3//Ar process (400 V Ar ion beam) are achieved. These low temperatures have allowed us to utilize UV-baked photoresists as well as PMMA as etch masks, facilitating very simply process development. Higher substrate temperatures (+50/spl deg/C to +120/spl deg/C) yield still higher etch rates, but at the expense of severely degraded surface morphologies. An InGaAsP/InP (1.55 /spl mu/m) bulk laser with one facet etched the other cleaved is demonstrated, and compared with a both facets cleaved laser.