EFFECTS OF DISLOCATION AND STRESS ON CHARACTERISTICS OF GAAS-BASED LASER GROWN ON SI BY METALORGANIC CHEMICAL VAPOR-DEPOSITION

The thermally induced biaxial tensile stress in GaAs/Si is reduced by postgrowth patterning, and the reduction in stress is dependent on the pattern size and shape. For narrow stripe patterns the stress relief is obtained perpendicular to the stripe. For small square patterns the stress is relieved in both directions. Thermal cycle annealing is also effective in reducing the threading dislocations in GaAs/Si. A thermally cycle-annealed multi-quantum-well (MQW) laser on a Si substrate grown by metalorganic chemical vapor deposition has continuous threshold current as low as 24 mA at 300 K. Rapid degradation can be suppressed by postgrowth patterning for the thermally cycle-annealed laser with an 8-mu-m-wide stripe, which results from the reduction of the biaxial stress to the uniaxial stress.