The effect of phosphorus ion implantation on molybdenum/silicon contacts

Abstract

Formation of Mo/Si contacts by implantation of phosphorus ions was studied. The implantation was carried out at temperatures of −196, 25, and 150 °C and a fluence ranging between 1015 and 1017 ions cm−2. The morphological and structural characterizations were done with scanning electron microscopy, transmission electron microscopy, and x-ray diffraction. Hexagonal MoSi2 phase was identified in samples implanted with more than 1016 ions cm−2 at all three implantation temperatures. Traces of MoP were found in the sample implanted with 1017 ions cm−2 at 150 °C. Measured effective contact resistance showed ohmic behavior in as-implanted samples except for samples implanted with 1015 ions cm−2 at 150 °C. Smooth surfaces of implanted MoSi2 structures remained after post-implant annealing at 850 °C for 1/2 h in H2 ambient. The effect of post-implant annealing is also discussed in terms of doping, microstucture, and contact resistance.