Method of fabricating nonvolatile memory device

A method of fabricating nonvolatile memory devices may involve forming separate floating gates on a semiconductor substrate, forming control gates on the semiconductor substrate, conformally forming a buffer film on a surface of the semiconductor substrate, injecting ions into the semiconductor substrate between the pairs of the floating gates to form a common source region partially overlapping each floating gate of the respective pair of the floating gates, depositing an insulating film on the buffer film, etching the buffer film and the insulating film at side walls of the floating gates and the control gates to form spacers at the side walls of the floating gates and the control gates, and forming a drain region in the semiconductor substrate at a side of the control gate other than a side of the control gate where the common source region is formed.