Method for forming dual gate in dram embedded with a logic circuit

Abstract

A method for forming a dual gate of a semiconductor device includes the steps of sequentially stacking a gate insulating film, a semiconductor layer, and a low resistance metal layer on a semiconductor substrate having a first well of a first conductivity type and a second well of a second conductivity type, forming first and second gate patterns that include the semiconductor layer and the low resistance metal layer on the substrate corresponding to the first and second wells, forming sidewall spacers at sides of the first and second gate patterns, and exposing the first well and the first gate pattern, implanting impurity ions of the second conductivity type into the exposed first well and the first gate pattern to form a first source and a first drain, exposing the second well and the second gate pattern, implanting impurity ions of the first conductivity type into the exposed second well and the second gate pattern to form a second source and a second drain; and diffusing the impurity ions from the low resistance metal layer into the semiconductor layer to form first and second gate electrodes.