Capacitors, three-dimensional

Designing a specific material architecture. 3D hierarchical carbon [79,80], 3D aperiodic [79,81,82] or highly-ordered hierarchical carbons are representative samples with multimodal pore structure to optimize the performance of the capacitors. The micropore, mesopore and macropore structure of such three-dimensional hierarchical carbons are generally perfectly interconnected. 

In any real memory device the capacitors take up most of the chip area the transistors and resistors are very small. Therefore the FRAM roadmap [8] shown in Table 2 mandates a fully three-dimensional (3D) capacitor structure in the industry by 2008. The state of the art at present is a PZT-lined trench, a Tokyo Institute of Technology-Samsung collaboration that achieves a 6.5 1 aspect ratio for the trenches. Ru electrodes are used, prepared from the organic precursor Ru-DER, from Tosoh Corp. 

MOSFETs. The metal-oxide-semiconductor field effect transistor (MOSFET or MOS transistor) (8) is the most important device for very-large-scale integrated circuits, and it is used extensively in memories and microprocessors. MOSFETs consume little power and can be scaled down readily. The process technology for MOSFETs is typically less complex than that for bipolar devices. Figure 12 shows a three-dimensional view of an n-channel MOS (NMOS) transistor and a schematic cross section. The device can be viewed as two p-n junctions separated by a MOS capacitor that consists of a p-type semiconductor with an oxide film and a metal film on top of the oxide. 

The constant drive to miniaturize components for communications devices is stimulating efforts to develop LTCC technology into three dimensional circuitry in which passive components (resistors, capacitors and inductors) are packaged into the structure with the active, integrated circuits, bonded to the outer surface. The technology is reviewed by W. Wersing et al. [18]. 

On the other hand, there are applications shown in Figure 27.1 that are not effectively met by CSD. For example, integrated capacitors for dynamic random access memory (DRAM) node elements require a much higher capacitance density, extremely small lateral dimensions, and three-dimensional architectures. For... 

Nonvolatile FeRAM devices ntilize either PZT or SET derivatives. In low density memory FeRAM prodncts, CSD is frequently nsed as the deposition method. For high-density 4- or 32-Mbit FeRAM prototypes, CSD is still used by industry to fabricate ferroelectric PZT thin-fihn capacitors, although gas phase methods like MOCVD have advantages due to the potential for conformal coverage of small three-dimensional strnctures. 

Three-dimensionally ordered porous materials have been applied to electrochemical energy conversion systems, such as Uthium battery, fuel cell, and electrochanical double layer capacitor. Based on this technique, functional materials for other applications can be produced. The advantages of three-dimensionally ordered materials are based on micro or nano size ordered pores. 

Zhou, Q., Li, Y, Huang, L., Li, C., Shi, G., 2014. Three-dimensional porous graphene/polyaniline composites for high-rate electrochemical capacitors. J. Mater. Chem. A 2,17489-17494. 

To push memory densities beyond 64 Mbits using Si02 or ONO dielectrics it has been necessary to develop very complicated three-dimensional structures such as trench capacitors. 

Vu, A., X. Y. Li, J. Phillips et al. 2013. Three-dimensionally ordered mesoporous (3DOm) carbon materials as electrodes for electrochemical double-layer capacitors with ionic liquid electrolytes. Chemistry of Materials 25 4137-4148. 

Xiao, J. W, S. X. Yang, L. Wan, F. Xiao, and S. Wang. 2014. Electrodeposition of manganese oxide nanosheets on a continuous three-dimensional nickel porous scaffold for high performance electrochemical capacitors. Journal of Power Sources 245 1027-1034. 

Kim et al. electrochemically deposited PPy on a CNT/silica film substrate using a potential cycling method at room temperature. After removal of silica with hydrofluoric acid (HF), CNT/PPy composites with controlled pore size in a three-dimensional (3D) entangled structure of a CNT film were prepared as electrode materials for a pseudo-capacitor [36]. The pore size of the final CNT/PPy composite film could be controlled by changing the amount of silica in the mixed suspension of CNTs and nanosize silica. The SC of the CNT/PPy composite with 83.4 wt.% PPy was 250 F/g at a potential scan rate 10 mV/s in 1.0 mol/L KCl and it decreased by only 15% to 211 F/g at 500 mV/s. 

Itoi H, Nishihara H, Kogure T, Kyotani T (2011) Three-dimensionally arrayed and mutually connected 1.2-NmNanopores for high-performance electric double layer capacitor. J Am Chem Soc 133 1165-1167... 

Lin J, MiUler S, Obermeier E (1991) Two-dimensional and three-dimensional as basic elements for chemical sensors interdigital capacitors. Sens Actuators B 5 223-226... 

A fuel cell electrode is porous and three-dimensional instead of flat. Its thickness varies at different locations. The reaction rates can be quite different from point to point due to the endless differences in the three-phase boundaries. The current distribution is not homogeneous at either micro- or macro-levels. For example, the inlet regions normally have higher current densities than the outlet regions. All these factors (three dimensions, uneven thickness, heterogeneous reaction rates, and uneven current distribution) could attribute to the double layers behaving differently from a pure capacitor. 

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