Analysis of inductively coupled argon plasma-enhanced quantum-well intermixing process for multiple bandgap implementation

The inductively coupled argon (Ar) plasma-enhanced quantum-well intermixing has been investigated for the implementation of multiple bandgaps in an InGaAs/InGaAsP quantum-well laser structure. Multiple bandgap control is achieved by controlling the local defect concentrations without manipulating the critical rapid thermal annealing process using a multi-step plasma exposure or a spatial defect modulation. The interdiffusion process is found to obey Fick's law and enhanced by the near-surface point defects after a short plasma exposure time. For a prolonged exposure, the enhancement is reduced attributed to the possible formation of defect clusters. With single-step plasma exposure, the defect concentrations, thus intermixing degree, can be controlled using a variable window opening. This work demonstrates the practical approaches of multiple bandgap creation suitable for the photonic-integrated circuit application.