Plasma-induced quantum well intermixing for the universal high-density photonic integration

The quantum well intermixing has been developed for tuning the bandgap of III–V compound semiconductor materials using Argon plasma at the postgrowth level. The inductively coupled plasma shows an advantage of a larger blue-shift with a narrower linewidth than the plasma generated using reactive ion etching system. A wide range of III–V compound material systems covering the wavelength range from 700 to 1600 nm has been intermixed using the technique. Using the multiwidth quantum-well probe structure, the intermixing mechanism was investigated. The point defects are created at near sample surface during plasma exposure and upon annealing they propagate downwards to promote quantum-well intermixing. Such technique gives a spatial resolution of better than 2.5 μm utilizing the stress inducing SixNy mask. The extended cavity laser has been demonstrated using selective plasma induced intermixing with a low loss intermixed waveguide of ∼2.3 cm−1. The result indicates a promising approach of lateral bandgap tuning for high-density photonic integrated circuits at postgrowth level using a plasma system widely used in the semiconductor industry.