Capacitance Analysis of Highly Leaky MIM Capacitors Using Time Domain Reflectometry

Characterization of metal-insulator-metal (MIM) capacitors with a scaled dielectric is a challenge using conventional capacitance-voltage (C-V) measurements due to a high leakage current. In this letter, a method to analyze MIM capacitance that is more immune to the leakage current problem has been successfully demonstrated using time domain reflectometry (TDR). The TDR method can be applied to Al₂O₃ MIM capacitors with a capacitance density up to ~ 11.1 fF/μm², for which an impedance analyzer has failed to measure capacitance at 1 MHz. Differences in the voltage coefficient of capacitance and dielectric constant (k) were also investigated.