Ay. Lew et al., INTERFACE STRUCTURE IN ARSENIDE PHOSPHIDE HETEROSTRUCTURES GROWN BY GAS-SOURCE MBE AND LOW-PRESSURE MOVPE/, Journal of electronic materials, 26(2), 1997, pp. 64-69
We have used cross-sectional scanning tunneling microscopy (STM) to st
udy interface structure in arsenide/phosphide heterostructures grown b
y gas-source molecular beam epitaxy (GSMBE) and by low-pressure metalo
rganic vapor phase epitaxy (LP-MOVPE). High-resolution images of GSMBE
samples consisting of GaAs interrupted at 200 Angstrom intervals with
a 40 s P-2 flux reveal substantial; growth-temperature-dependent inco
rporation of phosphorus with nanometer-scale lateral variations in int
erface structure. STM images of InGaAs/InP multiple quantum well struc
tures grown by LP-MOVPE show evidence of interface asymmetry and exten
sive atomic cross-incorporation at the interfaces. Data obtained by ST
M have been corroborated by high-resolution x-ray diffraction and refl
ection high-energy electron diffraction. Together, these studies provi
de direct information about nanometer-scale grading and lateral nonuni
formity of arsenide/phosphide interfaces that can occur under these gr
owth conditions.