High-density MIM capacitors using Al₂O₃ and AlTiO_x dielectrics

Abstract

We have investigated the electrical characteristics of Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> 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 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> are obtained for Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> 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 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> MIM capacitor as evidenced from the small frequency dependence, low leakage current, good reliability, small temperature coefficient, and low loss tangent.