RF, DC, and reliability characteristics of ALD HfO2-Al2O3 laminate MIM capacitors for Si RF IC applications

Abstract

High-performance metal-insulator-metal capacitors using atomic layer-deposited HfO2-Al2O3 laminate are fabricated and characterized for RF and mixed-signal applications. The laminate capacitor can offer high capacitance density (12.8 fF/μm2) up to 20 GHz, low leakage current of 4.9 × 10-8 A/cm2 at 2 V and 125°C, and small linear voltage coefficient of capacitance of 211 ppm/V at 1 MHz, which can easily satisfy RF capacitor requirements for year 2007 according to the International Technology Roadmap for Semiconductors. In addition, effects of constant voltage stress and temperature on leakage current and voltage linearity are comprehensively investigated, and dependences of quadratic voltage coefficient of capacitance (α) on frequency and thickness are also demonstrated. Meanwhile, the underlying mechanisms are also discussed.