BE-ZN INTERDIFFUSION AND ITS INFLUENCE ON INGAASP LASERS FABRICATED BY HYBRID GROWTH OF CHEMICAL BEAM EPITAXY AND METALORGANIC VAPOR-PHASE EPITAXY

We have studied the dopant redistribution between a chemical beam epit axy (CBE) frown InGaAsP laser structure and a metalorganic vapor phase epitaxy overgrown InP layer. Secondary ion mass spectroscopy analysis reveals that Zn and Be atoms deeply interdiffuse in the adjacent InP layers for a Zn doping of 10(18) cm(-3) and that a fraction of Zn atom s go through the CBE InP and penetrate the laser structure guide layer . We have found that the Zn outdiffusion is significantly suppressed b y reducing the Be doping concentration from 10(18) to 5 X 10(17) cm(-3 ). As a result, for tensile-strained InGaAsP multiquantum well (MQW) b uried-heterostructure (BH) lasers, the threshold current and internal loss decrease from 13 to 9 mA and 15 to 10 cm(-1) by lowering the Be d oping, respectively. InAsP MQW BH lasers have an internal loss of 5.5 cm(-1). (C) 1997 American Institute of Physics.