Mechanism for phosphorus deactivation in silicon-based Schottky diodes submitted to MW-ECR hydrogen plasma

摘要

Current work reveals the deactivation mechanism of phosphorus in silicon-based Schottky diodes. Microwave plasma power (P-MW) was fixed at 650W to observe the variation in different operational parameters of diodes such as initial phosphorus concentration, flux and hydrogenation temperature (T-H) and process time (t(H)). The analysis of variation in concentration of phosphorus by hydrogenation has been carried out by capacitance-voltage (C-V) measurements to monitor the doping activation/deactivation. The results clearly show that the atomic species H+ is dominant in the reactors MW-ECR plasma. Therefore, the rates and depth of neutralization were obtained in the low phosphorus-doped silicon sample. The H+ becomes H-0 and prefers an interaction with another H-0 instead of gaining an electron to become a negative ion. The hydrogenation temperature study indicates that the deactivation rate of phosphorus is achieved in a complex manner. Indeed, as the hydrogenation temperature increases, deactivation of phosphorus also increases till saturation at 250 degrees C. At higher temperature, low or even no phosphorus-hydrogen complex exists due to their thermal dissociation. The same behavior was confirmed by long hydrogenation.