Contamination of BF_2~+ Beam and the Effects on Implantation Junction Depth
BF_2~+注入束的沾污和对结深的影响

The BF_2~+ beam can be contaminated by BF~+,F~+ and B~+ beams with different energies dueto the collisions between BF_2~+ and the remaining gas moleculae in the system. It is unfavourablefor shallow junction formation because the junction depth would be increased remarkably asshown by the SIMS results. Three methods of removing or decreasing the contamination beamsare presented.