CELL STRUCTURE FOR ONE TIME PROGRAM ROM WHEREIN SOURCE REGIONS OF EACH CELL HAS ITS OWN CONTACT, AND METHODS FOR PROGRAMMING AND READING THE OTP ROM

摘要

An OTP(One Time Program) ROM cell structure having a contact formed at a source region of each cell and a method for programming and reading a ROM are provided to perfectly break down a fuse by preventing degradation of a current flowing on a selected transistor. A gate electrode(33) is formed on a first thick dielectric stacked on a substrate. A fuse is formed to be separated from the gate electrode. A drain electrode is placed between the gate electrode and the fuse. The fuse includes a fuse electrode(35) formed on a second thick dielectric layered on the substrate and on the first dielectric. The dielectric is broken down when a predetermined voltage is applied to the fuse electrode. A bit line(39) is electrically connected to the fuse electrode through a first contact(38). A word line(34) applies a voltage to the gate electrode. A source region is electrically connected to a metal line(41) through a second contact(40).