High-density MIM capacitors using Al2O3 and AlTiOx dielectrics

We have investigated the electrical characteristics of Al2O3 and AlTiOx MIM capacitors from IF (100 KHz) to RF (20 GHz) frequency range. Record high capacitance density of 0.5 and 1.0 muF/cm(2) are obtained for Al2O3 and AlTiOx MIM capacitors, respectively, and the fabrication process is compatible to existing VLSI backend integration. However, the AlTiOx MIM capacitor has very large capacitance reduction as increasing frequencies. In contrast, good device integrity has been obtained for Al2O3 MIM capacitor as evidenced from the small frequency dependence, low leakage current, good reliability, small temperature coefficient, and low loss tangent.