Dose: As we have seen before, increasing the dose leads not only to a thicker layer of SiO2, but also to a more sharply defined boundary. A typical value for implantation of O+ ions is 10e18/cm2. For a given energy level, there exists a maximum dose after which the surface crystallinity will be lost.
Energy: Increased energy leads to increased depth of the SiO2 layer. There exists a lower limit of energy below which the surface crystallinity cannot be maintained. Implant energies are typically on the order of 100 keV.
Implant temperature: Typical implant temperatures range from 550-600 C. Lower temperatures result in less recrystallization during implanting.
Annealing temperature: Current processes generally specify that annealing be carried out at very high temperatures--1300 C or greater. The melting point of silicon is around 1400 C. Such high temperatures allow for the silicon to recrystallize and for SiO2 precipitates to dissolve. However, even annealing at the melting point will only decrease the dislocation density by about an order of magnitude. (Baumgart, 112)