High-Performance Metal-Insulator-Metal Capacitors Using Amorphous Ba Ti4 O9 Thin Film

Amorphous, 70 nm thick Ba Ti4 O9 film grown at 350°C exhibited a high capacitance density of 4.58 fFμ m2 at 100 kHz, which decreased slightly to 3.7 fFμ m2 at 6.0 GHz. It had a relatively high Q factor of 80 at 3 GHz. The leakage current density of the film was ∼1.07 nA cm2 at 1 V and the leakage current mechanism was considered to be Schottky emission. The quadratic and linear voltage coefficients of capacitance of the film were -65.4 and -44.0 ppmV at 100 kHz, respectively. The temperature coefficient of capacitance of the film was also low about 126.6 ppm°C at 100 kHz. These results confirm that the amorphous Ba Ti4 O9 film can be used as a high performance metal-insulator-metal capacitor.