Low-resistance nonalloyed ohmic contacts to Si-doped molecular beam epitaxial GaAs

Kirchner, P. D.; Jackson, T. N.; Pettit, G. D.; Woodall, J. M.
July 1985
Applied Physics Letters;7/1/1985, Vol. 47 Issue 1, p26
Academic Journal
We have found evidence that the surface depletion charge density in molecular beam epitaxial n-GaAs doped heavily with Si approaches the Si concentration. In situ metallization of the as-grown surface of GaAs uniformly doped with Si at 1×1020 cm-3 yields a specific contact resistivity of 1.3 μΩ cm2, indicating a space-charge density about equal to the silicon density despite a measured bulk electron density of 4×1018 cm-3. This contact resistivity is among the lowest for nonalloyed ohmic contacts to n-GaAs. We attribute the large discrepancy between surface space-charge density and bulk electron density to the amphoteric behavior of silicon in GaAs. Surface Fermi-level pinning and arsenic stabilization create a surface depletion region where donor site selection predominates, whereas the extrinsic electron density in the bulk causes self-compensation.


Related Articles

  • Delta-doped ohmic contacts to n-GaAs. Schubert, E. F.; Cunningham, J. E.; Tsang, W. T.; Chiu, T. H. // Applied Physics Letters;8/4/1986, Vol. 49 Issue 5, p292 

    A new type of nonalloyed ohmic contact to GaAs is realized by molecular beam epitaxy. The ohmic characteristic of the metal-semiconductor junction is obtained by placing a highly δ-doped donor layer a few lattice constants away from the metal-semiconductor interface of the contact and thus...

  • Contact resistances of NiGeAu, PdGeTiPt, and TiPd ohmic contacts to GaAs and their temperature dependence from 4.2 to 350 K. Jones, K. A.; Linfield, E. H.; Frost, J. E. F. // Applied Physics Letters;12/30/1996, Vol. 69 Issue 27, p4197 

    The specific contact resistance (rc) of NiGeAu and PdGeTiPt ohmic contacts to n-GaAs and TiPd and PdGeTiPt ohmic contacts to p+-GaAs were determined as a function of temperature between 4.2 and 350 K. The low rc obtained for some of the contacts at 4.2 K implies that much of the total contact...

  • Very low resistance nonalloyed ohmic contacts using low-temperature molecular beam epitaxy of GaAs. Patkar, M.P.; Chin, T.P. // Applied Physics Letters;3/13/1995, Vol. 66 Issue 11, p1412 

    Explores very low resistance ohmic contacts using low-temperature molecular beam epitaxy of gallium arsenide films. Improvement of film stability; Protection of high space charge density layer on the surface; Result of heavy beryllium doping.

  • Extremely low nonalloyed and alloyed contact resistance using an InAs cap layer on InGaAs by molecular-beam epitaxy. Peng, C. K.; Chen, J.; Chyi, J.; Morkoç, H. // Journal of Applied Physics;7/1/1988, Vol. 64 Issue 1, p429 

    Examines the formation of extremely low alloyed and nonalloyed ohmic contact resistances on n-type InAs cap layer on InGaAs by molecular-beam epitaxy. Information on the samples; Method used in evaluating the contact resistances; Conclusion of the study.

  • Improved contacts to semi-insulating GaAs photoconductive switches using a graded layer of InGaAs. Kuchta, D.; Whinnery, J. R.; Smith, J. S.; Woodall, J. M.; Pettit, D. // Applied Physics Letters;10/8/1990, Vol. 57 Issue 15, p1534 

    High performance photoconductive switches are demonstrated using a molecular beam epitaxy grown graded layer of InxGa1-xAs to make an ohmic contact to semi-insultating GaAs. It is found that the graded layer results in a peak signal amplitude that is more than a factor of 2 larger than what is...

  • Effects of substrate preparation conditions on GaAs oval defects grown by molecular beam epitaxy. Fujiwara, K.; Nishikawa, Y.; Tokuda, Y.; Nakayama, T. // Applied Physics Letters;3/17/1986, Vol. 48 Issue 11, p701 

    Effects of substrate preparation conditions, i.e., wet chemical and ultrahigh vacuum cleaning preparations, on GaAs oval defects grown by molecular beam epitaxy (MBE) were investigated. It is found that, with our MBE system, the presence of the smaller (<10 μm) ovally shaped defects without...

  • Nucleation and initial growth of GaAs on Si substrate. Rosner, S. J.; Koch, S. M.; Harris, J. S. // Applied Physics Letters;12/29/1986, Vol. 49 Issue 26, p1764 

    The microstructure of thin layers of GaAs grown on Si substrates at low growth temperatures by molecular beam epitaxy was examined using transmission electron microscopy and MeV 4He+ ion channeling angular scan analysis. Crystalline island formation is observed at temperatures as low as 325...

  • Device quality growth and characterization of (110) GaAs grown by molecular beam epitaxy. Allen, L. T. P.; Weber, E. R.; Washburn, J.; Pao, Y. C. // Applied Physics Letters;8/31/1987, Vol. 51 Issue 9, p670 

    Device quality (110)GaAs has been reproducibly grown by molecular beam epitaxy (MBE) for the first time. Angling of the substrate to expose stable, Ga-rich ledges on the (110) surface has been shown to be the necessary condition for two-dimensional growth. The layers exhibit a room-temperature...

  • Effect of substrate tilting on molecular beam epitaxial grown AlGaAs/GaAs lasers having very low threshold current densities. Chen, H. Z.; Ghaffari, A.; Morkoç, H.; Yariv, A. // Applied Physics Letters;12/21/1987, Vol. 51 Issue 25, p2094 

    Single quantum well, graded refractive index separate confinement heterostucture (SQW GRINSCH) lasers with well thicknesses in the range of 65–480 Å have been grown by molecular beam epitaxy (MBE) on (100) and off of (100) by 4° toward (111) A substrates. The threshold current...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics