Ultra-low Contact Resistivity of PtHf Silicide Utilizing Dopant Segregation Process

We investigated the dopant segregation (DS) process for PtHf silicide to realize low contact resistivity. After the patterning of SiO 2 hard mask and heavily doped n + diffusion region formation on p -Si(100) substrates, 20 nm-thick PtHf-alloy thin film with 10 nm-thick HfN encapsulating layer was deposited in situ utilizing a PtHf-alloy target by RF magnetron sputtering at room temperature. Then, PH 3 ion implantation was carried out for DS followed by silicidation at 450–500°C/5–60 min in N 2 /4.9%H 2 ambient. After Al electrode formation, a sintering process was carried out at 400°C/20 min in N 2 /4.9%H 2 ambient. Ultra-low contact resistivity was achieved for fabricated PtHSi with a DS process on the order of 2.5 × 10 −8 Ω cm 2 evaluated by the cross-bridge Kelvin resistor method.