TRANSMISSION ELECTRON-MICROSCOPY STUDY OF RAPID THERMALLY ANNEALED PDGE CONTACTS ON IN0.53GA0.47AS/

Phase for?nation in rapid thermally annealed Pd/Ge contacts on In0.53G a0.47As has been investigated by means of cross-sectional transmission electron microscopy, convergent-beam electron diffraction, and energy -dispersive x-ray analysis. Solid-phase regrowth is observed to occur similarly as in Pd/Ge contacts or? GaAs or InP. The reaction starts at low temperatures with the formation of an amorphous Pd-In-Ga-As layer , which crystallizes al elevated temperatures yielding hexagonal Pd4In 0.53Ga0.47As being first described in this work. At temperatures >250 degrees C, this phase decomposes due to epitaxial solid-phase regrowth of In0.53Ga0.47As and formation of Pd-Ge phases. The stable compositi on is reached at temperatures >350 degrees C with excess Ge diffused t hrough top Pd-Ge to the contact interface and growing epitaxially on t he semiconductor. (C) 1996 American Institute of Physics.