ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Tungsten was deposited on GaAs using a low-temperature laser-chemical vapor deposition process. A KrF excimer laser beam incident perpendicularly on a GaAs surface was found to induce metallic W formation from a gas mixture containing WF6 and SiH4 at laser energy densities as low as 25 mJ/cm2. In-situ x-ray photoelectron spectroscopy analysis shows that SiH4 plays an important role in the initiation of metallic W deposition at such low laser energy densities. Scanning electron microscopy of the W films shows a dense and regular columnar structure. Auger depth profiles show that the deposited W is pure. No impurities such as F, C, or O were observed, with a detection limit of 1 at. %, and the interdiffusion between W and GaAs is minimal. X-ray diffraction shows that the W film is mostly in the stable, highly conductive α phase, as confirmed by the low resistivity value of 21 μΩ cm. Metallic W features of 60 μm on GaAs were obtained by laser direct-projection patterning. I–V measurements show that the W–GaAs structures formed provide good quality Schottky contacts, with an average barrier height of 0.71 eV and an average ideality factor of 1.2. To our knowledge, these are the first Schottky diodes obtained using a laser based resistless projection patterning process on GaAs. © 1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.365199
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