Capacitance Density Comparison of PECVD Silicon Oxynitride and Silicon Nitride Dielectric for MIM Capacitor

In this work, we compare capacitance density of MIM capacitors between PECVD Silicon Nitride (SiN) and PECVD Silicon Oxynitride (SiON). Process parameters for both dielectrics are different in term of gasses, refractive index, and dielectric constant, while thicknesses are similar. The capacitors are tested on two different test structures, which are stand alone and matching cells. The size of the cell is 90×90um2. Our measurements show that SiN capacitors are superior to SiON capacitors in terms of higher capacitance density and lower matching variation.