AVS 45th International Symposium
    Electronic Materials and Processing Division Wednesday Sessions
       Session EM2-WeA

Paper EM2-WeA3
The Structure of InAs/AlSb/InAs Surfaces and Interfaces Grown by MBE

Wednesday, November 4, 1998, 2:40 pm, Room 316

Session: Application of Scanning Probes to Electronic Materials
Presenter: B.Z. Nosho, University of California, Santa Barbara
Authors: B.Z. Nosho, University of California, Santa Barbara
W.H. Weinberg, University of California, Santa Barbara
B.V. Shanabrook, Naval Research Laboratory
B.R. Bennett, Naval Research Laboratory
W. Barvosa-Carter, Naval Research Laboratory
L.J. Whitman, Naval Research Laboratory
Correspondent: Click to Email
We have used in-situ plan-view scanning tunneling microscopy to study the surfaces and interfaces within an InAs/AlSb/InAs resonant tunneling diode-like structure grown by molecular beam epitaxy. The nanometer and atomic-scale morphologies of the surfaces have been characterized following a number of different growth procedures. When InAs(001)-(2x4) is exposed to Sb@sub 2@ a bilayer surface is produced, with one monolayer-deep (3 Å) vacancy islands covering approximately 25% of the surface. Both layers exhibit a (1x3)-like reconstruction characteristic of an InSb-like surface terminated with >1 ML Sb, indicating that there is a significant amount of Sb on the surface. When 5 ML of AlSb is deposited on an Sb-terminated InAs surface, the number of layers observed on each terrace increases to three. Growth of an additional 22 ML of InAs onto the AlSb layer, followed by a 30 s interrupt under Sb@sub 2@, further increases the number of surface layers observed. The rms roughness is found to increase at each subsequent interface; however, on all the surfaces the roughness is @<=@2 Å. The surface roughness is attributed to a combination of factors, including reconstruction-related stoichiometry differences and kinetically-limited diffusion during growth. To begin to elucidate these various factors and help distinguish between kinetic and thermodynamic effects, we have examined the initial stages of Sb@sub 2@ deposition on InAs(001)-(2x4) under various growth conditions. Possible methods to reduce the roughness of the interfaces will be discussed.