GROWTH LIMITATIONS OF STRAINED MULTIPLE-QUANTUM WELLS

The growth limitations of strained multiple quantum wells are studied theoretically. A dynamic strain relaxation model is developed to estim ate both the critical layer thickness for barrier and well of multiple quantum well InxGa1-xAs/GaAs device structures. According to the calc ulations, if the well and barrier growth temperatures are 480 and 550- degrees-C for a 30% indium 50 angstrom four-quantum-well structure, th e minimum barrier thickness is around 150 angstrom, and for a 20% indi um 40 angstrom thirty-quantum-well structure, the barrier layer thickn ess could be as thin as 200 angstrom. This model should prove useful i n optimizing practical strained-layer device structures.