Metal wires, such as W, Mo, and Ta, can be boronized to become sinks of B atoms by heating them in the presence of a mixture of H-2 and H3NBH3 or (BH)(3)(NH)(3). These boronized wires behave as sources of B atoms when heated in vacuum. The density of B atoms released to the gas phase increases with the addition of H2 and can be >10(11) cm(-3), which is enough for surface doping. The release is stable and continues for more than several hours when boronized for 1 h. Since the metal wires are not nitrided, contamination by N atoms is not expected. H3NBH3 and (BH)3(NH)3 are not explosive, and wires boronized by these species can be used as safe and contamination-free sources of B atoms for surface doping. (C) 2016 Elsevier B.V. All rights reserved.