Xinming Huang

Effect of heavy boron doping on pressure-induced phase transitions in single-crystal silicon

The influence of applied loads and loading/unloading rates on pressure-induced phase transitions in lightly and heavily boron-doped silicon was systematically investigated. The resultant phases were plotted into two-dimensional maps with applied loads and loading/unloading rates as the coordinate axes. The formation region of the amorphous phase in the heavily boron-doped silicon was found to be much larger than that in the lightly boron-doped one, suggesting that heavy boron doping promotes the amorphization in silicon.

Dislocation-free CZ-Si crystal growth without the thin Dash-neck

It is found that dislocation-free Si crystal growth is possible without a thin neck. Dislocation behaviour in a heavily B-doped CZ-Si crystal has been analysed, and it is found that three kinds of dislocations generated due to thermal shock, lattice misfit and incomplete seeding must be suppressed to grow dislocation-free crystal without the thin Dash-neck. Heavily B-doped or Ge-doped Si seeds are useful in suppressing dislocation generation due to thermal shock, and heavily B- and Ge-codoped Si seeds not only suppress dislocation generation due to thermal shock most effectively but can also suppress that due to lattice misfit. A relative higher melt temperature at the start of pulling is suggested for suppressing the dislocation generation due to incomplete seeding. Dislocations were observed in crystals grown from an annealed heavily B-doped Si seed, and they were probably induced by the dislocation loops in the annealed seed.