MIM capacitors using atomic-layer-deposited high-/spl kappa/ (HfO2)/sub 1-x/(Al2O3)/sub x/ dielectrics

Metal-insulator-metal (MIM) capacitors with (HfO₂)/sub 1-x/(Al₂O₃)/sub x/ high-/spl kappa/ dielectric films were investigated for the first time. The results show that both the capacitance density and voltage/temperature coefficients of capacitance (VCC/TCC) values decrease with increasing Al₂O₃ mole fraction. It was demonstrated that the (HfO₂)/sub 1-x/(Al₂O₃)/sub x/ MIM capacitor with an Al₂O₃ mole fraction of 0.14 is optimized. It provides a high capacitance density (3.5 fF/μm²) and low VCC values (/spl sim/140 ppm/V²) at the same time. In addition, small frequency dependence, low loss tangent, and low leakage current are obtained. Also, no electrical degradation was observed for (HfO₂)/sub 1-x/(Al₂O₃)/sub x/ MIM capacitors after N₂ annealing at 400/spl deg/C. These results show that the (HfO₂)/sub 0.86/(Al₂O₃)/sub 0.14/ MIM capacitor is very suitable for capacitor applications within the thermal budget of the back end of line process.