Scaling of the surface migration length in nanoscale patterned growth
- Center for High Technology Materials, Department of Electrical and Computer Engineering, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico 87106 (United States)
Scaling of the surface migration length in nanoscale patterned growth (NPG) is investigated as a function of the lateral dimension L{sub M} of a mask film fabricated on a substrate for selective epitaxy. By reducing L{sub M} below the surface migration length, any nucleation on the mask is avoided through the evaporation and surface out-diffusion of adatoms. The upper limit of L{sub M} for NPG L{sub M,c} corresponds to the surface migration length on the mask. An equation, identical to that for two-dimensional step-flow growth, is derived for NPG. However, the boundary conditions at the substrate-mask interface are affected by the surface potential difference and are different from those at the terrace edges of a homogeneous stepped surface. This results in a scaling law for surface migration length, which is proportional to the diffusion constant D and the critical incident flux F{sub c} in the form (D/F{sub c}){sup 1/{alpha}} with {alpha} decreasing from 4 to 2 as evaporation becomes dominant. NPG of GaAs for L{sub M,c}{approx}200 nm({alpha}{approx}3.8) is demonstrated at {approx}600 deg. C with molecular beam epitaxy.
- OSTI ID:
- 21294019
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 15 Vol. 94; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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