Fabrication and characterization of the ultra shallow junction diode with cobalt silicide contact

The Co-silicides were formed from Co(200 Angstrom)/Ti(100 Angstrom) bilayer on the BF2+ ion implanted Si substrates by the rapid thermal annealing pro cess and evaluated in terms of the sheet resistances, the cross-sectional m orphologies, the crystallinites and the atomic species distributions. The s table CoSi2 crystal phases were obtained at the annealing temperature of 70 0 degrees C for 20 seconds and the sheet resistances were decreases from 48 .5 Ohm/square to 4.7 Ohm/square according to the increase of the annealing temperature from 600 degrees C to 800 degrees C. In the fabrication of the p(+)-n shallow junction diodes, the Co(120 Angstrom)/Ti(40 Angstrom) bilaye r was used to reduce the silicide thickness up to 500 Angstrom. From the SI MS analysis results, we found that the emitter junction depth including sil icide layer was about 0.14 mu m. The p(+)-Si/silicide/Al structure exhibite d the Kelvin resistance of 1.2 Ohm through the contact area of 10x10 mu m(2 ) and the specific contact resistance of 1.2x10(-6) Ohm . cm(2). The applic ation of Co/Ti bilayer silicide contact on the p(+)-n ultra shallow junctio n resulted in the improvement of ideality factor as well as the reduction o f source-drain sheet resistance and specific contact resistance.