Low-temperature CAIBE processes for InP-based optoelectronics

We have developed Cl2 /Ar and IBr3 /Ar chemicaily-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 (approximately equal 0 deg. C). Etch rates of 400-750 Ae "AU"/min and excellent surface morphologies at substrate temperatures between minus 5 deg. C and plus 10 deg. C with both Cl2 /Ar and IBr3 /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 (plus 50 deg. C to plus 120 deg. C) yield still higher etch rates, but at the expense of severely degraded surface morphologies. An InGaAsP/InP (1.55 micrometer) bulk laser with one facet etched the other cleaved is demonstrated and compared with a bothfacets cleaved laser