Developments of new complex materials using mime and interface diffusion of the supersaturated alloy elements in thin films

经高温退火后，Cu（Ti）膜与SiO_2/Si衬底之间形成了薄的富Ti扩散势垒层。这项技术被称为“扩散势垒的自我形成”，对超大规模集成（ULSI）互连的制造具有吸引力。此外，我们研究了该技术在Cu（Ti）合金薄膜上的适用性，这些薄膜沉积在四个低介电常数（low-k）介电层上，这些介电层是未来ULSI-Si器件的潜在介电层。利用透射电子显微镜（TEM）和二次离子质谱（SIMS）分析了Cu（Ti）薄膜的微观结构，并将其与薄膜的电学性能进行了相关性分析。结果表明，Cu(Ti)/介电层样品均形成了富Ti界面层。控制自形成富钛界面层组成的主要因素是介电层中的C浓度，而不是Ti化合物（TiC和TiSi）的形成焓。当C浓度大于17 at.%时，在介质层上形成结晶TiC。

Thin Ti-rich diffusion barrier layers were found to be formed at the interface between Cu(Ti) films and SiO_2/Si substrates after annealing at elevated temperatures. This technique was called "self-formation of the diffusion barrier," which is attractive for fabrication of ultra-large scale integrated (ULSI) interconnects. Furthermore, we investigated the applicability of this technique to Cu(Ti) alloy films which were deposited on the four low dielectric constant (low-k) dielectric layers which are potential dielectric layers of future ULSI-Si devices. The microstructures were analyzed by transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS), and correlated with the electrical properties of the Cu(Ti) films. It was concluded that the Ti-rich interface layers were formed in all the Cu(Ti)/dielectric-layer samples. The primary factor to control composition of the self-formed Ti-rich interface layers was the C concentration in the dielectric layers rather than the formation enthalpy of the Ti compounds (TiC and TiSi). Crystalline TiC was formed on the dielectric layers with a C concentration higher than 17 at.%.