Stress compensation in GaAs–Al0.24 Ga0.76 As1−y Py LPE binary layers

To improve the performance and reliability of heterostructure GaAs lasers, it is important to reduce stress in the epitaxial layers caused by lattice mismatch between GaAs and AlxGa1−xAs. More precise measurements than previously available have been made on the lattice mismatch of binary layers of GaAs–Al0.24Ga0.76As1−yPy and GaAs–Al0.36Ga0.64As1−yPy from radius-of-curvature measurements. The heterostructures were grown by LPE, with various atom fractions of P, on (100) and (211) GaAs substrates. Liquidus values of P concentration at 780°C growth temperature to achieve room-temperature lattice matching have been determined to ±4%. The threshold value of the lattice mismatch and layer thickness product on (211) substrates necessary to avoid misfit dislocations is given.