The effect of doping different contents of Ni on the thermal stability of Cu(Ni) alloy films has been investigated. Cu(Ni) films with different Ni contents were deposited on SiO₂/Si substrates by magnetron sputtering, then annealed in vacuum at 350°C to 650°C for 0.5 h. X-ray diffraction analysis and resistance measurements revealed that high-resistance copper silicide was formed after annealing at 450°C for the Cu(Ni, 1.66 at.%) and Cu(Ni, 9.16 at.%) samples. However, no copper silicide was observed for Cu(Ni, 3.59 at.%) even after annealing at 650°C. Transmission electron microscopy provided evidence for a ∼ 25-nm self-formed barrier layer at the Cu/SiO₂ interface with Cu(Ni, 3.59 at.%). The failure to form a diffusion barrier for the Cu(Ni, 1.66 at.%) sample resulted from its low Ni doping concentration, which was insufficient to produce such a self-formed layer during annealing. The barrier failure was caused by grain refinement due to the increased Ni content, providing diffusion channels for atom diffusion. The results clearly suggest that addition of an appropriate amount of Ni can improve the thermal stability of Cu(Ni)/SiO₂/Si interconnect structure materials.

研究了掺杂不同含量的Ni对Cu（Ni）合金膜热稳定性的影响。通过磁控溅射将具有不同Ni含量的Cu（Ni）膜沉积在SiO ₂ / Si衬底上，然后在350°C至650°C的真空中退火0.5小时。X射线衍射分析和电阻测量表明，在450°C退火后，Cu（Ni，1.66 at。％）和Cu（Ni，9.16 at。％）样品形成了高电阻硅化铜。但是，即使在650℃退火后，也未观察到Cu（Ni，3.59at。％）的硅化铜。透射电子显微镜为在Cu / SiO ₂处形成约25 nm的自形成势垒层提供了证据与Cu（Ni，3.59 at。％）的界面。Cu（Ni，1.66 at。％）样品未能形成扩散势垒是由于其低的Ni掺杂浓度，不足以在退火过程中产生这种自形成层。势垒失效是由于镍含量增加而导致的晶粒细化导致的，从而为原子扩散提供了扩散通道。结果清楚地表明，添加适量的Ni可以改善Cu（Ni）/ SiO ₂ / Si互连结构材料的热稳定性。