We investigated the thermal stability of NiSi using Ni-Ta alloy films on Si(100) substrate. After silicidation using one-step rapid thermal processing (RTP) at 500°C for 30 s, uniform NiSi layers were formed from both Ni/Si and Ni-Ta/Si systems. To compare thermal stability of NiSi formed by RTP at 500°C, an additional annealing was performed in a furnace at 600°C for 120 min after a self-aligned silicide (SALICIDE) process. In the Ni-Ta/Si system, the silicide layer exhibited a NiSi phase and a stable sheet resistance of 5 Ω/□ even after furnace annealing at 600°C for 120 min. In the Ni/Si system, however, the sheet resistance dramatically increased with an increase of annealing time due to phase transition from NiSi to NiSi2. X-ray diffraction data and transmission electron microscopy images also suggest that the thermal stability of NiSi was remarkably improved by addition of Ta. In addition, it is confirmed that Ni0.90Ta0.10 film does not react with any dielectric materials (SiO2,Si3N4) at an annealing temperature of 500°C. Conclusively, the experimental results strongly suggest that Ni-Ta film could be applicable to high performance sub-0.1 μm devices for SALICIDE processes.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Science(all)
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering