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

Abstract

The metal-insulator-metal (MIM) capacitors with (HfO2)1-x(Al2O3)x high-κ 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 fFμm2) and low VCC values (∼ 140ppm/V2) 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 N2 annealing at 400 °C. 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.