Effects of hydrogen plasma on dislocation motion in silicon

We have measured the velocity of dislocation glide motion in phosphorus-doped FZ-silicon during hydrogen plasma irradiation, and, have found for the first time that the velocity was drastically promoted under hydrogen plasma by a factor of 10 to 100 in the temperature range of 390-480°C, and the activation energy of dislocation motion was reduced to 1.2eV from the value 2.3eV, in the dark. We exclude the possibility that the observed phenomenon is due to so called radiation-enhanced dislocation glide induced by plasma light, since no enhancement of dislocation motion occurred at all under nitrogen plasma with the same light intensity as hydrogen plasma, and hydrogen plasma irradiation with covers to prevent light exposure promoted dislocation motion as well. In addition, it is confirmed by spreading resistance measurements that hydrogen atoms were actually incorporated up to about 10 μm beneath the surface to passivate boron. This assures us that hydrogen atoms were incorporated to enough depths at the temperatures where dislocation velocity was measured. These results clearly indicate that hydrogen itself enhances dislocation motion. Some discussions are made on the enhancement mechanisms of dislocation motion.