Abstract: A metal code process for a read-only memory (ROM) combines the alignment dip back process (to reduce the polyoxide thickness over the gate electrode and to protect the field oxide) with a double charge implant approach to provide the function of a depletion mode ROM cell. The alignment dip back process also avoids leakage current problems. A stable depletion mode device character is achieved by implant step energies greater than 150 keV.

Abstract: This invention relates to the fabrication of integrated circuit devices and more particularly to an improved, graded, silicon oxynitride process step, in order to form an unconventional dielectric layer, having an adjustable effective dielectric constant, for the purpose of fabricating capacitors for both DRAM and Logic technologies. During the special CVD process for the oxynitride layer, its composition is varied such that three distinct regions are created in the direction of film growth. The dielectric property of the lower region is close to silicon oxide, the dielectric property of the upper region is close to silicon oxynitride and the dielectric property of the intermediate transition zone is between that of silicon oxide and oxynitride.