| 摘要 |
PURPOSE:To provide a high speed and uniformization of the performance by forming the film thickness of the floating gate thinner than the lower-layer polysilicon layer constituting the polycide control gate, thereby preventing the increase and scattering of the word line resistance. CONSTITUTION:The film thickness d1 of a floating gate 4 is formed thinner than the film thickness d2 of a lower-layer polysilicon layer 6 constituting a polycide control gate CG. For instance, on the floating gate 4 consisting of a first polysilicon layer having a thickness of 1500-2000Angstrom , the polycide control gate CG consisting of a second polysilicon 6 having a thickness of 2000Angstrom or greater and a WSi2 layer 7 having a thickness of the order of 2000Angstrom is provided through a second gate oxide film 5 having a thickness of the order of 300-500Angstrom which was formed by thermal oxidation. With this, the coverage of an upper- layer silicide layer constituting the word line in the floating gate step section can be improved and the increase of the word line resistance due to the disconnection of the silicide layer and the reduction of the film thickness can be prevented, thereby enabling the operation speed to be improved. |
