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

Abstract

The metal-insulator-metal (MIM) capacitors with (HfO2)(1-x)(Al2O3)(x) high-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 the mole fraction of Al2O3. It was demonstrated that the (HfO2)(1-x)(Al2O3)(x) MIM capacitor with a Al2O3 mole fraction of 0.14 is optimized. It provides a high capacitance density (3.5 fF/muM(2)) and low VCC values (similar to 140 ppm/V-2) at the same time. In addition, small frequency dependence, low loss tangent, and low leakage current are also obtained. Also, no electrical degradation was observed for (HfO2)(1-x)(Al2O3)(x) MIM capacitors after N-2 annealing at 400 degreesC. All these show that the (HfO2)(0.86)(Al2O3)(0.14) MIM capacitor is very suitable for the capacitor applications within the. thermal budget of the back end of line process.