Contents I. Introduction
Selective Area Metal-Organic Vapor Phase Epitaxy (SA-MOVPE) of InGaAsP is effective for the monolithic integration of semiconductor optical devices [1]–[3]. By SA-MOVPE with an appropriate mask pattern, we can fabricate multiple quantum wells (MQWs) of InGaAsP with various bandgaps in a single growth, which reduces the number of etching and regrowth processes. Semiconductor optical amplifier is a key component for monolithically integrated photonic devices, and polarization independent feature is strongly demanded. Previous studies successfully demonstrated polarization insensitive semiconductor amplifier (SOA) [3]–[7]. However, monolithic integration of polarization insensitive SOA and passive components using wide stripe SAG has not been demonstrated yet because of difficulties in growth due to unclear mechanism in SA-MOVPE. Especially, since tensile-strained wells are required. for polarization insensitive gain feature, relaxation of strain occurs easily. Furthermore, evaluation of strain in selective area is much more difficult than that in planar region. X-ray diffraction is typically used for evaluation of strain in planar region. However, that method is not applicable in narrower selectively-grown area. In order to demonstrate monolithically integrated photonic devices by selective area growth, control of MQWs and its strain is necessary. Therefore, estimation of strain, thickness, photoluminescence (PL) peak wavelength from planar region is important.
