High-density RF MIM capacitors using high-k La2O3 dielectrics

Abstract

The integrity of the metal-insulator-metal (MM) capacitor with high-k La2O3 dielectrics formed using a 400degreesC back-end process was investigated. A very high capacitance per unit area of 9.2 fF/mum(2) was achieved for La2O3 MIM capacitors at 1 MHz, significantly reducing the chip size of radio frequency (rf) circuits. A mathematical derivation, involving measured S parameters, yielded the small voltage-dependent capacitance (DeltaC/C) less than or equal to 100 ppm at 1 GHz, indicating that the precision capacitor circuit can be applied in the rf regime. Furthermore, such a high capacitance density can be maintained as the frequency is increased from 10 KHz to 20 GHz with a large Q factor greater than or equal to90. (C) 2004 The Electrochemical Society.