Ultrathin High-Density Capacitors based on Carbon Nanofibers Fabricated on Silicon, Alumina and Glass Interposer Materials

We demonstrate the suitability of carbon nanofiber based MIM capacitors (CNF-MIM) to be implemented on various substrates such as silicon, glass and alumina for prospective use as discrete or integrated passives on chips or interposers. The capacitors themselves are only 5 μm thick. However, capacitance densities larger than 300 nF/mm² have been measured on all substrates including a 30-μm thick silicon substrate. The 5 μm thick capacitors feature ESR values in the range of 100 mΩ, ESL below 10 pH and leakage currents as low as 0.01 nA/nF at 1 V with device breakdown at 6 V, which makes them a promising candidate both for highly integrated, multifunctional on-chip and discrete miniaturized electronic components.