The interface roughness of a GaAs/AlGaAs/InGaAs double-barrier-quantum-well
structure was controllably altered by changing substrate surface misorient
ation and growth interruption time at metal organic vapor-phase epitaxy (MO
VPE) growth interfaces. Atomic force microscopy (AFM) and X-ray reflectance
measurements were used to quantify the interface roughness. The InGaAs qua
ntum wells grown on singular substrates exhibit an island growth mode morph
ology, while step-bunched growth is observed on the misoriented substrates.
A short growth interruption time, of typically similar to 15 s, can decrea
se the InGaAs/AlGaAs interface roughness. The low-temperature I-V character
istics of the resonant tunneling diodes based on this quantum-well structur
e are found to be sensitive to the quantum-well interface roughness. The me
asured interfacial roughness was used as input to a numerical simulation of
device performance. (C) 1998 Elsevier Science B.V. All rights reserved.