Oxidation of Au/Si Films For Self-Confined Interconnects

We have explored the possibility of oxidizing a Au/Si composite layer or a Au-Si alloyed layer on SiO2 substrates to form a highly conductive narrow line with a protective SiO2 layer over it. A number of sample configurations and annealing ambients have been investigated. It was found that co-evaporated Au-Si alloys ( ∼30 at. % Au) showed no oxide formation for annealing temperatures between 200°C and 800°C in a flowing O2 ambient (annealing time ≃ 2.25hrs). Samples with a configuration of SiO2/Au/Si showed mixing of the Au and Si layers, but no appreciable oxide formation until after annealing at 800°C in a flowing O2. Samples with a configuration of SiO2/Si/Au, however, showed uniform and smooth oxide growth on top of the Au layer after annealing in air at 200°C. The structural and electrical properties of the self-confined Au lines will be discussed. This process may be potentially useful for narrow interconnects on VLSl chips.