The behavior of high energy multiple P + (0.5–7.5 MeV) and B + implanted silicon and rapid thermal annealing

Abstract

Three kinds of composite profiles have been obtained using an Ionex 1.7 MeV Tandem ion implanter. The P + ions were implanted into p-type (111) silicon at energies ranging from 0.5 to 7.5 MeV and with a dose ranging from 3.6×10 12 to 2.0×10 13 cm −2. This was followed by the implantation of B + ions with energies ranging from 50 to 100 keV and with doses in the range from 5×10 13 to 5×10 15 cm −2. The annealing of the specimens was carried out by rapid thermal anneal (RTA). The carrier concentration profiles were measured using a spreading resistance probe (SRP). In order to investigate the defects and stress of the implanted specimens, the depth distribution of the residual defects in the implanted layer was observed after RTA by high voltage electron microscopy (HVEM) using cross-sectional measurement techniques. Samples are free from defects when they were implanted with MeV P +, except there is a dark band in the implanted layer which is in the region of lattice distortion. After the B + implantation, the residual defects are obviously apparent, the density of which increases with B + ion dose. The stress in the specimens was also measured by infrared laser photoelastic techniques, the results of which indicate that the stress within the P + implanted layer is much less than that induced by the phosphorus diffusion process. The value of the stress decreases as the anneal time increases, and increases with increasing ion dose.