铜(钛)和铜(铬)自形成阻挡层性能表征

采用直流磁控溅射法分别将Cu (Ti)和Cu (Cr)合金层沉积在SiO2/Si衬底上,随后将制得的样品在真空(2×10-3 Pa)中退火1h,退火温度为300 ～ 700℃.对Cu (Ti)及Cu (Cr)自形成阻挡层进行对比研究,通过X射线衍射(XRD)、X射线光电子能谱(XPS)和透射电子显微镜(TEM)观察并表征样品的微观结构.通过半导体分析仪测试样品的电学性能,并分析了其热稳定性.结果表明,在Cu膜中分别加入少量的Ti或Cr可使Cu沿〈111〉晶向择优取向生长.两种样品交界面处的Cu及Si元素含量迅速下降,表明在交界面处自形成阻挡层,抑制了Cu与Si元素之间的扩散.Cu (Ti) /SiO2/Si和Cu (Cr) /SiO2/Si样品漏电流测试结果表明,Cr自形成的阻挡层具有更好的热稳定性.

Performance Characterization of Cu (Ti) and Cu (Cr) Self-Forming Barrier Layer

Cu (Ti) and Cu (Cr) alloy layers were deposited separately on SiO2/Si substrates by the DC magnetron sputtering method directly and subsequently the samples were annealed in vacuum (2× 10-3 Pa) at 300-700 ℃ for 1 h.The comparative study of Cu (Ti) and Cu (Cr) self-forming barrier layers was carried out.The microstructure of the samples were observed and characterized by X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM).The electrical properties of the samples were measured by the semiconductor analyzer,and the thermal stability of the interconnect was analyzed.The results show that the addition of a small amount of Ti or Cr to the Cu film allows the Cu to grow along a preferential〈 111 〉crystal orientation.The contents of Cu and Si elements at the interface of the two samples were rapidly decreased,which indicated that the barrier layer self-formed at the interface restrained the interdiffusion between Cu and Si.The measured results of leakage currents of Cu (Ti) /SiO2/Si and Cu (Cr) /SiO2/Si samples show that the selfforming barrier layer of Cr has better thermal stability than that of Ti.