Epitaxial Ge films have been grown on [001]GaAs by laser photochemical vapor deposition (LPVD) for substrate temperatures (Ts) in the 285≤Ts≤415 °C interval. Films 400–700 A thick were grown at rates up to ∼1 A s−1 (0.6–5 nm/min) by photodissociating GeH4 with an ArF (193 nm) laser in parallel geometry (i.e., laser beam passes above and parallel to substrate). The quality of the Ge/GaAs heterointerfaces has been examined by plan‐view and cross‐sectional transmission electron microscopy. Convergent beam electron diffraction, selected area diffraction patterns, and lattice images show the LPVD films to be epitaxial, whereas films grown in the absence of ultraviolet laser radiation (i.e., by conventional chemical vapor deposition) are amorphous (Ts=305 °C) or heavily defected polycrystalline (Ts=415 °C). Epitaxy apparently hinges on the laser production of a species which migrates more than 10–60 mean free paths to reach the substrate (or is collisionally transformed en route into a more stable species) and ...
[1]
K. Suzuki,et al.
Laser‐assisted chemical vapor deposition of Si: Low‐temperature (<600 °C) growth of epitaxial and polycrystalline layers
,
1985
.
[2]
H. Beneking,et al.
Epitaxial growth of Ge on GaAs substrates
,
1983
.
[3]
A. Christou,et al.
Smooth and continuous Ohmic contacts to GaAs using epitaxial Ge films
,
1978
.
[4]
S. A. Piette,et al.
Laser Photochemical Vapor Deposition of Ge Films (300 ≤ T ≤ 873 K) from GeH 4 : Roles of Ge 2 H 6 and Ge
,
1986
.
[5]
Robert Sinclair,et al.
The preparation of cross‐section specimens for transmission electron microscopy
,
1984
.