TY - JOUR
T1 - Processing and dielectric properties of nanocomposite thin film "supercapacitors" for high-frequency embedded decoupling
AU - Raj, P. Markondeya
AU - Balaraman, Devarajan
AU - Govind, Vinu
AU - Abothu, Isaac Robin
AU - Wan, Lixi
AU - Gerhardt, Rosario
AU - Swaminathan, Madhavan
AU - Tummala, Rao
N1 - Funding Information:
Manuscript received May 3, 2006; revised April 22, 2007. This work was supported by the National Science Foundation (NSF) through the NSF ERC in Electronic Packaging (EEC-9402723) at the Georgia Institute of Technology. This work was recommended for publication by Associate Editor L. Li upon evaluation of the reviewers’ comments. P. M. Raj, V. I. R. Abothu, R. Gerhardt, M. Swaminathan, and R. Tum-mala are with the Georgia Insitute of Technology Atlanta, GA 30332-0560 USA (e-mail: [email protected]). D. Balaraman is with ATD, Intel Corporation, Chandler, AZ 85226 USA. V. Govind is with Jacket Micro Devices (JMD), Atlanta, GA 30308 USA. L. Wan is with the Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100864, China. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TCAPT.2007.901736
PY - 2007/12
Y1 - 2007/12
N2 - The embedded decoupling capacitor problem has been pursued by several groups and industry around the world over the past decade. Currently, popular ceramic-polymer composites can only provide limited capacitance, typically within 10 nF/cm 2. With the reliability and processing constraints imposed, the capacitance density would be much lower. Newer capacitor concepts such as supercapacitors can overcome the limitations of existing polymer based capacitors and are now being considered. These concepts rely on nanostructured electrodes for high surface area per unit volume resulting in ultrahigh capacitance densities and unconventional polarization mechanisms such as electrical double layer and interfacial polarization. Supercapacitive structures lead to ultrahigh capacitance densities of the order of hundreds of microfarads. However, manufacturers report that the properties are unstable at high frequencies, typically even at tens of megahertz. To adapt these structures for mid-to-high-frequency decoupling, it is hence essential to systematically characterize the high-frequency dielectric properties of the thin nanocomposite films and nanostructured electrodes. This paper reports complete electrical characterization of a part of such a system, carbon black-epoxy nanocomposites. The high-frequency properties of the cured films were evaluated with a multiline calibration technique by measuring S-parameters of transmission lines fabricated on the top of the dielectrics. Though the nanostructured carbon black epoxy composites showed high dielectric constant of 1000 at low frequencies, the high frequency (0.5-4.5 GHz) dielectric constant was found to be only up to 10 times that of the base polymer matrix. The measured dielectric constant at gigahertz frequencies increased from 15-30 when the filler content was increased from 3.8% to 6.5%, with excessive leakage currents. Based on these measurements, conduction and polarization relaxation mechanisms will be assessed and the suitability of the thin film supercapacitors for high-frequency decoupling applications will be discussed.
AB - The embedded decoupling capacitor problem has been pursued by several groups and industry around the world over the past decade. Currently, popular ceramic-polymer composites can only provide limited capacitance, typically within 10 nF/cm 2. With the reliability and processing constraints imposed, the capacitance density would be much lower. Newer capacitor concepts such as supercapacitors can overcome the limitations of existing polymer based capacitors and are now being considered. These concepts rely on nanostructured electrodes for high surface area per unit volume resulting in ultrahigh capacitance densities and unconventional polarization mechanisms such as electrical double layer and interfacial polarization. Supercapacitive structures lead to ultrahigh capacitance densities of the order of hundreds of microfarads. However, manufacturers report that the properties are unstable at high frequencies, typically even at tens of megahertz. To adapt these structures for mid-to-high-frequency decoupling, it is hence essential to systematically characterize the high-frequency dielectric properties of the thin nanocomposite films and nanostructured electrodes. This paper reports complete electrical characterization of a part of such a system, carbon black-epoxy nanocomposites. The high-frequency properties of the cured films were evaluated with a multiline calibration technique by measuring S-parameters of transmission lines fabricated on the top of the dielectrics. Though the nanostructured carbon black epoxy composites showed high dielectric constant of 1000 at low frequencies, the high frequency (0.5-4.5 GHz) dielectric constant was found to be only up to 10 times that of the base polymer matrix. The measured dielectric constant at gigahertz frequencies increased from 15-30 when the filler content was increased from 3.8% to 6.5%, with excessive leakage currents. Based on these measurements, conduction and polarization relaxation mechanisms will be assessed and the suitability of the thin film supercapacitors for high-frequency decoupling applications will be discussed.
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U2 - 10.1109/TCAPT.2007.901736
DO - 10.1109/TCAPT.2007.901736
M3 - Article
AN - SCOPUS:36849040465
SN - 1521-3331
VL - 30
SP - 569
EP - 578
JO - IEEE Transactions on Components and Packaging Technologies
JF - IEEE Transactions on Components and Packaging Technologies
IS - 4
ER -