Characterization of phosphorus implantation in 4H-SiC

We report the characterization of phosphorus implantation in 4H-SiC. The implanted layers are characterized by analytical techniques (secondary ion mass spectrometry, transmission electron microscopy) as well as electrical and a sheet resistance value as low as 160 Ohm/square has been measured. We have also studied the effect of annealing time and temperature on activation of phosphorus implants. It has been shown to be possible to obtain low sheet resistance (similar to 260 Ohm/square) by annealing at a temperature as low as 1200 degrees C. High-dose (similar to 4 x 10(15) cm(-2)) implants are found to have a higher sheet resistance than that on lower dose implants which is attributed to the near-surface depletion of the dopant during high temperature anneal. Different implantation dosages were utilized for the experiments and subsequently junction rectifiers were fabricated. Forward characteristics of these diodes are observed to obey a generalized Sah-Noyce-Shockly multiple level recombination model with four shallow levels and one deep level.