HIGH-RESOLUTION TEM AND XRD STUDY OF INTERFACE COMPOSITION INHOMOGENEITIES IN CBE AND MOCVD GROWN IN (GAAS)P/INP MULTIPLE-QUANTUM WELLS

In(As)P/InP and InGaAs(P)/InGaAs ''false'' QWs have been investigated for studying interface compositional changes during the growth. An As and P incorporation depth of about 3-4 monolayers, quite independent of the growth conditions both for CBE and MOCVD samples, was found. The As and P concentration increased by increasing the growth interruption time, the dominant effect being the group V atom incorporation at the InGaAs/InP heterointerfaces. Further, contamination effects (carry over) of As atoms in the growth chamber were also observed in lattice matched MQW laser structures. Finally, HREM and high resolution x-ray diffraction investigations of the same structures revealed different amounts of elastic strain at the InGaAs/InP and InP/InGaAs interfaces.