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Journal of the Korean Ceramic Society 2001;38(10): 871. |
Effect of Dopants on Cobalt Silicidation Behavior at Metal-oxide-semiconductor Field-effect Transistor Sidewall Spacer Edge |
Jong-Chae Kim, Yeong-Cheol Kim, Byung-Kook Kim1 |
Department of Materials Engineering, Korea University of Technology and Education 1Division of Materials, Korea Institute of Science and Technology |
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ABSTRACT |
Cobalt silicidation at sidewall spacer edge of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) with post annealing treatment for capacitor forming process has been investigated as a function of dopant species. Cobalt silicidation of nMOSFET with n-type Lightly Doped Drain (LDD) and pMOSFET with p-type LDD produces a well-developed cobalt silicide with its lateral growth underneath the sidewall spacer. In case of pMOSFET with n-type LDD, however, a void is formed at the sidewall spacer edge with no lateral growth of cobalt silicide. The void formation seems to be due to a retarded silicidation process at the LDD region during the first Rapid Thermal Annealing (RTA) for the reaction of Co with Si, resulting in cobalt mono silicide at the LDD region. The subsequent second RTA converts the cobalt monosilicide into cobalt disilicide with the consumption of Si atoms from the Si substrate, producing the void at the sidewall spacer edge in the Si region. The void formed at the sidewall spacer edge serves as a resistance in the current-voltage characteristics of the pMOSFET device. |
Key words:
Cobalt silicidation, Void, Lightly doped drain (LDD), Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) |
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