Annealing effects on electrical property depth profiles of BF 2 and P implanted polycrystalline Si determined by differential hall effect metrology

Differential Hall effect metrology (DHEM) was used to accurately and effectively evaluate the carrier concentration, mobility, and resistivity depth profiles at nano-scale resolution for BF 2 and P implanted poly-Si layers after RTA (750–950 °C) and CO 2 laser (115–135 W) annealing. Microstructure was characterized by transmission electron microscopy (TEM), total dopant concentration was measured by secondary ion mass spectrometer (SIMS). After implantation, the amorphous-Si (a-Si) surface was found to recover fully by RTA annealing, however a residual a-Si layer remained at the surface after CO 2 laser annealing. The carrier concentration and active ratio at the a-Si regrowth region was higher than deeper into the samples. The active ratio could reach ~ 100% at the regrowth region for the CO 2 laser annealed samples, but the mobility values deteriorated due to impurity scattering. Away from the regrowth region near the surface, RTA could produce higher carrier concentration and active ratio compared to CO 2 laser annealing. The suitable carrier concentration value was ~ E + 19 #/cm 3 to obtain relatively high mobility of ~ 40 cm 2 /V s for the BF 2 and P implanted poly-Si. The resistivity was related to the carrier concentration and to the presence of the a-Si residue at the surface. It was demonstrated that DHEM in conjunction with SIMS and TEM can be successfully employed to evaluate, in detail, the electrical properties in ultra-shallow junctions of poly-Si and to correlate these electrical properties to process conditions.