TW279259B - Making method of electrostatic discharge device - Google Patents

Abstract

A making method of electrostatic discharge device, that is applicable to one silicon substrate, comprises the steps of: forming field oxide on the silicon substrate to separate general function device area and electrostatic discharge device area; forming one gate oxide on the surface of general function device area and the electrostatic discharge device; forming one polysilicon on the gate oxide top; through mask defining, etching the polysilicon and gate oxide to construct gate electrode, and expose silicon substrate surface where will be formed as source/drain of general function device area and electrostatic discharge device area, then performing one ion implantation process to form lightly doped area; forming one oxide on the surface of general function device area and the electrostatic discharge device; coating first photoresist on oxide of electrostatic discharge device area surface, with one electrostatic discharge device mask defining pattern, then etching, removing oxide on general function device area surface, but forming spacer on lateral side of gate electrode of general function device area; with gate electrode and spacer of the general function device area as mask, performing ion implantation process to form heavily doped area, completing one lightly doped source/drain structure, removing the first photoresist on oxide of the electrostatic discharge device area; forming one Ti metal film on general function device area by sputtering deposition, by rapid thermal annealing process, combined with etching process to form self-aligned SiTi on the above gate electrode surface and exposed source/drain surface; coating second photoresist on general function device area, defining pattern by the electrostatic discharge device mask, then etching oxide of electrostatic discharge device area surface; with gate electrode of electrostatic discharge device area as mask, performing ion implantation process to form heavily doped area, removing the second photoresist on the general function device area, completing device making.