Nuclear Instruments and Methods in Physics Research B 84 (1994) 190-194 North-Holland NW zyxwvutsrqponm B Beam Interactions with Materials 8 Atoms Identification of EOR defects due to the regrowth of amorphous layers created by ion bombardment B. de Mauduit a, L. Lahab a, C. Bergaud b, M.M. Faye a, A. Martinez b and A. Claverie a a zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA CEM ES - LOE/CNRS, B.P. 4347, 31055 Toulouse Cedex, France b LAAS/CNRS, 7 avenue du Colonel Roche, 31077 Toulouse Cedex, France In this paper TEM investigations have been carried out on typical EOR defects found in Ge-amorphized (001) wafers (Ge + Si, 150 keV, 2X1015 ions/cm’) after thermal annealing (RTA, looo”C, 10 s). These defects consist of medium sized (lo-50 nm) dislocation loops that have been characterized by conventional electron microscopic techniques. Most of them ( - 75%) are circular faulted Frank loops with b = a/3(111) vectors. The remaining ( - 25%) loops are perfect elongated hexagon-shaped loops: they have nearly (111) habit planes, with b = a /2( 101) vectors. Hence, it is possible to deduce from only one TEM image the number of Si atoms available in the loops as well as the density of the loops for different implantation or annealing conditions. This is needed for optimization of process conditions. 1. Introduction The formation of amorphous layers by ion bom- bardment prior to the introduction of a dopant or any other chemical impurity has several advantages over direct implantation in semiconductors. A preamor- phization step eliminates channelling problems and results in abrupt dopant profiles [l]. More generally, the fact that the incorporation of the dopant or the formation of some alloy (like SiGe) occurs during an- nealing through the solid phase epitaxial (SPE) re- growth of the u-layer is desirable because defect-free regrown layers can be obtained with required stoi- chiometry and electrical characteristics in most cases [2]. By contrast, it is well known that after SPE re- growth, structural defects are formed beneath the for- mer c/a interface. These defects have received the strange name of “EOR” - end-of-range defects. EOR defects are the only disadvantage of this technique because they are known to dramatically affect impurity diffusion [3] and also to be responsible for the leakage current when situated in a space-charge region of a device. However, for the mastering of the so-called preamorphization technique, a better knowledge of Fig. 1. Weak-beam image of both circular and elongated EOR loops seen near a [108] beam direction B using g = OaO, with positive s corresponding to a (g, 2g) condition. Loops in a variety of orientations are labelled according to the notation in table 1. 0168-583X/94/$07.00 0 1994 - Elsevier Science B.V. All rights reserved SSDI 0168-583X(93)E0371-M