We investigated the as-implanted profiles, electrical activation, diffusion, and recrystallization of gallium implanted in germanium samples through the combination of secondary-ion mass spectrometry, transmission electron microscopy, and sheet resistance measurement. Because of their high activation level (4.4 x 10(20) cm(-3)) without preamorphization, low activation temperature (400 degrees C), and absence of diffusion (up to 700 degrees C), Ga junctions in crystalline Ge are very promising candidates for implementation in germanium technology. In the amorphous Ge phase, an increased diffusivity of Ga was observed at temperatures above 400 degrees C. (C) 2009 The Electrochemical Society. [DOI:10.1149/1.3225204] All rights reserved.