| 초록 |
Metal silicides have been extensively used in modern Si-based semiconductor devices in recent years. Among the metal silicides, cobalt silicide has been greatly investigated for the application of interconnects and contacts in ultra-large-scale integration (ULSI) devices. The key advantages of Co-silicide are low resistivity and high thermal stability. Co-silicide structure is closely related to the diamond cubic structure of silicon and its lattice mismatch between CoSi2 and Si is about 1.2% at room temperature. Most Co-silicide has been produced mainly by the Physical Vapor Deposition (PVD) and Chemical vapor deposition (CVD) techniques. Co-silicide with PVD method provides good quality of thin film but also exhibits a problem of poor step coverage. CVD method is good to solve a step coverage problem but it generally contains a large amount of impurities due to the chemical reactions. To overcome these above mentioned problems, we introduced Remote Plasma ALD technique which is the technique to provide low impurity and high quality of thin film. In addition, we were also looking for the suitable precursors which should have a high volatility, a low decomposition temperature, and no premature decomposition. Based on these criteria, we studied the process for deposition Co from the metalorganic precursor which are cyclopentadienyl cobalt dicarbonyl, Co(C5H5)(CO)2, and Dicobalt octacarbonyl, Co2(CO)8. The crystal structure and microstructure of the films were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) respectively. The composition of the films was analyzed by Auger electron spectroscopy (AES). |
