COMPOSITIONAL ANALYSIS OF MOLECULAR-BEAM EPITAXY GROWN INYGA1-YAS GAAS/ALXGA1-XAS QUANTUM-WELLS BY DETERMINATION OF FILM THICKNESS/

The thickness of the individual layers of molecular beam epitaxy grown pseudomorphic InyGa1-yAs (0.1 less-than-or-equal-to y less-than-or-eq ual-to 0.35)/GaAs/Al0.3Ga0.7As quantum well structures has been determ ined by transmission electron microscopy (TEM), secondary ion mass spe ctrometry (SIMS) depth profiling, and reflection high energy electron diffraction (RHEED) with the aim of the compositional analysis of the ternary alloy films. Agreement between SIMS and TEM thickness data wit hin 15% is found. Reliable RHEED data at y greater-than-or-equal-to 0. 25, where the number of RHEED oscillations is drastically reduced by t he three-dimensional growth of the InGaAs film, have been obtained by averaging repeated RHEED measurements. As compared with TEM, RHEED ten ds to lower values by 10% at maximum. The compositional data determine d by the different methods including also photoluminescence (PL) agree within 20% in the technologically important region y greater-than-or- equal-to 0.2. At y = 0. 1, extreme accuracy requirements concerning th e thickness determination limit the accuracy of SIMS and TEM to around 30%. Therefore PL and RHEED are superior at this concentration. An in fluence of the growth temperature on the In content at y = 0.3 could b e detected only by PL, demonstrating the excellent relative accuracy o f PL.