Combination of transmission electron microscopy and secondary ion mass spectrometry methods and device characteristics are used to successfully study damage engineering of the B-based low energy ion implants. The depths and densities of the amorphizing (a-Si) layer (surface lattice damage) and the end of range (EOR) damage are found to correlate to ion mass (amu) and implant energy, which are scalable to the molecular ion implants and ultralow energy) implants. The B-11 beam-line implant shows thinner both a-Si and EOR depths due to its smaller amu and lower energy, and the damage are well annealed under the current annealing conditions. The BF2 beam-line implant shows severe surface lattice damage by more amorphizing due to its larger amu and higher energy, and needs more thermal budget to annealing (recrystallizing). The B2H6 plasma doping (PLAD) shows moderate a-Si layer and less EOR damage than beam-line ones which attributes to B deposition as a screen so that there are no direct ion bombardments on Si wafer substrate. The BF3 PLAD shows similar damage behavior to the BF2 beam-line implant but with less lattice damage. The device performance evaluation confirms that the device processed by B2H6 PLAD shows better I-ON versus I-OFF characteristics than those processed by BF2 and C2B10H12 molecular beam-line implants due to less damage and more complete annealing. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3431084]