A method for forming a floating gate semiconductor device such as an electrically
erasable programmable read only memory is provided. The device includes a silicon
substrate having an electrically isolated active area. A gate oxide, as well as
other components of a FET (e.g., source, drain) are formed in the active area.
A self aligned floating gate is formed by depositing a conductive layer (e.g.,
polysilicon) into the recess and over the gate oxide. The conductive layer is then
chemically mechanically planarized to an endpoint of the isolation layer so that
all of the conductive layer except material in the recess and on the gate oxide
is removed. Following formation of the floating gate an insulating layer is formed
on the floating gate and a control gate is formed on the insulating layer.
