Growth of High Quality Cobalt Metal Thin Film by Low Temperature UV-Assisted Atomic Layer Deposition
ZhengYong Liang1*, Yung-Chang Lin2, Chao-Hui Yeh1, Jui-Hsiung Liu3, Po-Wen Chiu1,4
1Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan
2National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
3Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
4Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
* Presenter:ZhengYong Liang,
Atomic layer deposition is a potential process for the deposition of various thin films such as diffusion barriers, liner materials and seed layers, which are required for state-of-the-art interconnects. In this study, Co thin film were deposited by UV-assisted atomic layer deposition using Co(CO)3NO as the Co precursor. The deposited Co films possess decent crystallinity and flatness. The UV-assisted process not only lower the deposition temperature, but also enhance the surface chemisorption, leading to an appreciable increase of deposition rate up to 5.1 Å/ cycle. The impurity contents were also minimized when the Co films deposited by remote plasma UV-ALD with hydrogen plasma in the process temperature range of 190-200 °C. From the XPS analysis, the cobalt and oxygen contents were about 98.2% and 1%, respectively, while the carbon and nitrogen residuals amount to less than 1%. In the flatness analysis by AFM, the RMS of the film deposited at 200 °C was observed to be 1.1 nm, while the film deposited at 180 °C has an RMS of 0.6 nm. After annealing at 350 °C for 15 min, the resistivity of the Co film with thickness of 55 nm can reach 1.0E-5 Ωcm.

Keywords: atomic layer deposition, cobalt, thin film, cobalt tricarbonyl nitrosyl, UV