High-density MIM capacitors using Al2O3 and AlTiOx dielectrics

We have investigated the electrical characteristics of Al ₂ O ₃ and AlTiO/sub x/ MIM capacitors from the IF (100 KHz) to RF (20 GHz) frequency range. Record high capacitance density of 0.5 and 1.0 μF/cm ² are obtained for Al ₂ O ₃ and AlTiO/sub x/ MIM capacitors, respectively, and the fabrication process is compatible to existing VLSI backend integration. However, the AlTiO/sub x/ MIM capacitor has very large capacitance reduction at increasing frequencies. In contrast, good device integrity has been obtained for the Al ₂ O ₃ MIM capacitor as evidenced from the small frequency dependence, low leakage current, good reliability, small temperature coefficient, and low loss tangent.