Terrace width evolution during step-flow growth with multiterrace adatom migration

Journal Article · Tue Jun 01 04:00:00 EDT 1993 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.354026· OSTI ID:6464138

Chalmers, S A; Tsao, J Y ^[1]; Gossard, A C ^[2]

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1. Sandia National Laboratories, Division 1311, Albuquerque, New Mexico 87185 (United States)
2. Materials Department, University of California, Santa Barbara, California 93106 (United States)

We have developed a computer-solvable model of step-flow growth that includes both anisotropic multiterrace adatom migration and asymmetric step edge attachment. We find that terrace widths equalize not only when each adatom preferentially attaches to the ascending step edge of the terrace that it lands on, but also when adatoms preferentially migrate over ascending step edges. This latter process can equalize long-range terrace width nonuniformities much more rapidly than can the former process. We also find that a slow lateral movement of terrace width distributions occurs when each adatom adheres to the step edges of the terrace that it lands on. More significantly, we find that a rapid lateral movement of terrace width distributions occurs when adatoms cross multiple step edges. This motion is especially fast when adatoms migrate distances that are comparable to or greater than the terrace width distribution period. We simulated the evolution of an experimentally observed (Al,Ga)Sb lateral superlattice (LSL) terrace width distribution, which led to quantitative estimates of the adatom migration characteristics present during the LSLs growth. At least one type of adatom, probably Ga, migrates nearly isotropically over many terraces. This method of determining adatom migration characteristics can be extended to any material system that allows LSL layers to be grown as terrace width markers.

• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6464138
• Journal Information: Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 73:11; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

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ANTIMONY COMPOUNDS
COMPUTERIZED SIMULATION
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