Positron beam profiling study of the metal-GaAs interface

• Published in: Applied surface science Vol. 116; pp. 256 - 262
• Main Authors: Ling, C.C., Weng, H.M., Hu, Y.F., Beling, C.D., Fung, S.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.1997; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Interface structure and roughness; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other interactions of matter with particles and radiation; Physics; Positron annihilation; Solid surfaces and solid-solid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Interface structure; Gold; Gallium arsenides; Annihilation; Tungsten; Size effect; Nickel; Experimental study; Positron beams
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/S0169-4332(96)01065-3

Properties of metal contacts on III–V semiconductors are dependent on the electronegativity of the metal. Generally metals have been classified into three categories according to their behaviour upon heat treatment. Au, Ni and W are the three metals belonging to different categories with the descending order of electronegativity. In this study a low energy positron beam has been used to investigate as-grown Au GaAs (SI), Ni GaAs (SI) and W GaAs (SI) samples with different thicknesses of metal overlayers. The method that has been employed is that of monitoring the Doppler broadening of annihilation radiation through S parameter measurements as a function of the beam energy. The S- E data were analysed by the program VEPFIT with different models and different implantation profiles. It is found that the interfacial information able to be extracted from the fitting is limited by present uncertainties in the implantation profile.