ABSTRACT
One of the most critical issues in Dynamic Random Access Memory (DRAM) cell designs is the fabrication of sufficient value reliable storage capacitance while cell size is continuously decreasing. While forming grained polycrystalline Si film for DRAM storage capacitor, it is important to determine its electrical properties. Leakage current density of the device with rough electrode is less than the area enhancement factor times that of the device with controlled poly-Si electrode. It is shown that morphology roughness and doping of the film strongly affect the electrical performance of the capacitor. Metal-insulator-metal capacitor structures using materials with increasing value of dielectric strength material like Ta2O5, Barium strontium titanate, HfO2, ZrO2, and layered combinations of some of these materials are taken up next. A different surface modifying method was developed by Y. H. Jun and others obtain a modulated stacked capacitor, in which surface area of the storage electrode was increased up to eight times that of an ordinary stacked capacitor.
