Dopant activation of heavily doped silicon-on-insulator by high density currents

Abstract
We have activated heavily boron-doped and arsenic-doped silicon-on-insulator (SOI) strips by applying electrical current. The SOI strips were implanted with 40 keV BF2+ or As+ at a dosage of 5×1015 ions/cm2. Without postimplantation annealing, these implanted SOI strips can be activated by applying a current up to 1×106 A/cm2, the resistance decreased from 8.80 to 0.61 kΩ for a 10 μm wide, 50 μm long, and 0.2 μm thick n+ silicon strip, for instance. This reduction of resistance is close to that obtained by the conventional postimplantation annealing at 900 °C for 30 min. To separate the effect of Joule heating from that of current activation, the temperature of the SOI strips during the current activation has been measured by Pt sensors. The result indicates that the temperature rise due to Joule heating is low and cannot explain the observed activation. We conclude that implanted dopants in Si can be activated by current stressing. To confirm it, carrier concentration obtained by Hall measurement is presented.