AVS 46th International Symposium
    Electronic Materials and Processing Division Thursday Sessions
       Session EM2-ThM

Paper EM2-ThM7
The Effective Two-step Passivation of Metal/GaAs Interface with Sulfur and Hydrogen Plasma

Thursday, October 28, 1999, 10:20 am, Room 612

Session: Dielectric Passivation/Oxides on Compound Semiconductors
Presenter: M.G. Kang, Yonsei University, Korea
Authors: M.G. Kang, Yonsei University, Korea
J.W. Kim, Yonsei University, Korea
H.H. Park, Yonsei University, Korea
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In application of GaAs to device integration, the reliable and controllable Schottky contact property of metal/GaAs is urgently necessary to yield. However, it is limited to develop furthermore due to the existence of defects at/near the metal/GaAs interface. In this study, a novel method of passivating the defects with sulfur and hydrogen plasma at/near the metal/GaAs interface was investigated. The sulfur-passivation was employed to passivate the defects at GaAs surface, and the defects in GaAs adjacent to the surface were co-passivated using hydrogen plasma. The native oxide of GaAs was completely removed by the surface treatment using HCl solution. The GaAs surface was then passivated with sulfur in a monolayer thickness using (NH@sub 4@)@sub 2@S@sub x@ solution. After the treatment, the surface could be protected from air-oxidation and preserved oxide-free-surface during a followed metallization. In particular, ultra thin Au metal of 5 nm thickness was deposited on the sulfur-passivated GaAs surface prior to hydrogen plasma treatment, in order to protect the GaAs surface from plasma-induced damage. The defect density of the metal/GaAs interface was greatly reduced by this two-step passivation method, compared to GaAs treated with either sulfur or hydrogen. The defects were evaluated by low temperature photoluminescence and deep level transient spectroscopy. The chemical bonding state of GaAs before and after Au-metallization was characterized using an angle-resolved X-ray photoelectron spectroscopic technique.