Enhanced Performance of Single Poly-Silicon EEPROM Cell With a Tungsten Finger Coupling Structure by Full CMOS Process

A single poly-silicon electrically erasable programmable read only memory cell with a tungsten finger coupling structure by fully compatible 0.13-μm CMOS process is proposed for the first time in this paper and its performances are compared with the conventional poly-silicon finger coupling cell. Results show that the tungsten finger coupling cell has smaller drain-induced barrier lowering effect, higher coupling ratio, and higher cell current and programming/erasing (P/E) speeds due to its metallic control gate and incremental capacitance from control gate structure. Furthermore, the reliability characteristics in this proposed tungsten finger coupling cell are comparable with poly-silicon finger coupling cell, and its P/E windows are wider during reliability tests.