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Morphology and microstructure of epitaxial Cu(001) films grown by primary ion deposition on Si and Ge substrates

Journal Article · · Journal of Applied Physics
DOI:https://doi.org/10.1063/1.363795· OSTI ID:397418
; ; ; ; ;  [1]; ;  [2]
  1. Department of Materials Science, the Materials Research Laboratory, and the Coordinated Science Laboratory, University of Illinois, Urbana, Illinois 61801 (United States)
  2. Department of Physics, Linkoeping University, S-581 83 Linkoeping (Sweden)

A low-energy, high-brightness, broad beam Cu ion source is used to study the effects of self-ion energy {ital E}{sub {ital i}} on the deposition of epitaxial Cu films in ultrahigh vacuum. Atomically flat Ge(001) and Si(001) substrates are verified by {ital in} {ital situ} scanning tunneling microscopy (STM) prior to deposition of 300 nm Cu films with {ital E}{sub {ital i}} ranging from 20 to 100 eV. Film microstructure, texture, and morphology are characterized using x-ray diffraction {omega}-rocking curves, pole figure analyses, and STM. Primary ion deposition produces significant improvements in both the surface morphology and mosaic spread of the films: At {ital E}{sub {ital i}}{gt}37 eV the surface roughness decreases by nearly a factor of 2 relative to evaporated Cu films, and at {ital E}{sub {ital i}}{approx_equal}35 eV the mosaic spread of Cu films grown on Si substrates is only {approx_equal}2{degree}, nearly a factor of 2 smaller than that of evaporated Cu. During deposition with {ital E}{sub {ital i}}{approx_equal}25 eV on Ge substrates, the film coherently relaxes the 10{percent} misfit strain by formation of a tilt boundary which is fourfold symmetric toward {l_angle}111{r_angle}. The films have essentially bulk resistivity with {rho}=1.9{plus_minus}0.1 {mu}{Omega}cm at room temperature but the residual resistance at 10 K, {rho}{sub 0}, shows a broad maximum as a function of {ital E}{sub {ital i}}, e.g., at {ital E}{sub {ital i}}{approx_equal}30 eV, {rho}{sub 0}=0.5 {mu}{Omega}cm. {copyright} {ital 1996 American Institute of Physics.}

Research Organization:
University of Illinois
DOE Contract Number:
FG02-91ER45439
OSTI ID:
397418
Journal Information:
Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 12 Vol. 80; ISSN JAPIAU; ISSN 0021-8979
Country of Publication:
United States
Language:
English