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.