Transmission electron microscopy was used to characterize structural defects in annealed implanted both at room temperature and at 200°C with at 150 keV. During implantation at room temperature an amorphous layer was formed to a depth of ∼1850Å, whereas no such layer was formed on the specimen implanted at 200°C. Upon recrystallization of the amorphous layer at 650°C or higher shear dislocations were observed as well as loop structures up to 2000Å in diameter on {111} and {110} planes within that region. Smaller, interstitial loops were present on {110} planes throughout the implanted region. The specimens implanted at 200°C did not go through a recrystallization stage. Therefore, no shear dislocations were formed in this case. However, these specimens when annealed to 650°C or higher contained loops under 100Å in size. The structural differences observed between the room temperature and 200°C implants may account for the higher carrier mobility measured for the 200°C implant.