Low contact resistivity of Ti/TiN/Al for NiSi₂ on epitaxial Si:P structure at full low-temperature process below 450 °C

Abstract

Combined with Ti/TiN/Al for ultra-thin NiSi 2 and in situ-doped Si:P, an ultra-low contact resistivity of 4.6 × 10 −9 Ω cm 2 was achieved under a low thermal budget (⩽450 • C). The in situ-doped Si:P layer was grown by molecular beam epitaxy at 350 • C with a high doping concentration of 1.2 × 10 21 cm −3 exceeding the solid solubility. On the Si:P substrate, ultra-thin NiSi 2 film of 12.8 nm was formed by low-temperature drive-in diffusion and alloying at 180 • C and 450 • C, respectively. The Ti/TiN/Al-NiSi 2 -Si:P scheme provides a solution to the dilemma between performance boosting and reliability degradation in advanced very-large-scale integration manufacturing technology. It can also be applied in future monolithic three-dimensional integration.