Low temperature high density Si3N4 MIM capacitor technology for MMMIC and RF-MEMs applications

In this work, a novel, high quality, high-density, deposited at room temperature ultra thin 5 nm Si3N4 metal insulator metal (MIM) capacitor process for monolithic millimetre-wave integrated circuit (MMMIC) applications is demonstrated. This process is developed using inductively coupled plasma enhanced chemical vapor deposition technique (ICP-CVD). Capacitance of 6.7 fF/μm2 and a breakdown electric field of more than 3 × 106 V cm−1 were achieved. RF characterisation and equivalent circuits models were extracted which showed an increase in capacitance per area by more than 13-fold and reduction in RF loss as silicon nitride thickness reduced from 120 to 5 nm. Comparison with high temperature conventional 300 °C PECVD Si3N4 showed comparable breakdown voltage and leakage current