Overgrowth of (In,Ga)(As,P) on rectangular-patterned surfaces using gas soruce molecular beam epitaxy

摘要

Integrated optical devices, such planar waveguide-coupled Bragg-resonant filters, are an important component for the implementation of thihg density, narrow bandwidth optical filtering in wavelength division multiplexed otical communication systems. However, accepable optical device performace of the filter is contingent upon the ability to maintain the integrity and profile of the as-fabricated rectangualr-patterned Bragg resoantors during eptiaxial overgrowth of the cladding layer. Bragg gratings are defiend in both InP substrates and InGaAsP epitaxial layers using X-ray lithography and reactive ion etching. The regrwoth process is initiated by removing the native oxide with a low temeprautre (～200 deg C) aomic hydrogen-assisted cleaning regimen that results in a grating that is unaltered from the desired as-etched rectnagular-patterned profile. The technqiues employed to presever the grating profile are described, and the microstructural and otical qualtiy of the strucutres are analyzed via scanning electron microscopy, triple axis X-ray diffractometry, and photoluminescnce.