Method for increasing surface area of a bottom electrode for a DRAM

摘要

A method of increasing a surface area of a bottom electrode for a DRAM. A polysilicon layer is formed. An etching process is performed and the polysilicon layer is etched into a surface having protrusions in order to increase the surface area of the polysilicon layer. A redox reaction is performed and the etched polysilicon layer is transformed to a metal layer by use of a solution; thus, the original appearance is still maintained. An annealing process is performed to concentrate the metal layer and further to reduce a thin-film leakage current.