Gate dielectric material

Fig. 6.3. Schematic overview and classification of gate-dielectric materials used in organic TFTs.

For a solution-processed active interface, in which either the gate dielectric material is deposited from solution on to a solution-processible semiconducting material or vice versa, it is critical to avoid dissolution or swelling effects during deposition of the upper layer, which can lead to interfacial mixing and increased interface roughness. The preferred approach to achieve this is to choose orthogonal solvents for the deposition of the multilayer structure [23]. 

Abstract. The design and synthesis of new molecular synthons for vapor-phase self-assembled nanodieletrics and silane crosslinkers for crosslinked polymer blend dielectrics is described. These dielectric films exhibit excellent dielectric properties with tunable thicknesses and capacitance values. These new gate dielectric materials are integrated into thin-film transistors based both p- and n-type organic semiconductors. 

Common polymers such as polystyrene (PS) and polymethylmethacrylate (PMMA) have been used as gate dielectric materials [7,20,46]. Their ready availability made them some of the early polymers investigated by researchers in the field [11,39,47]. However, the low capacitances of these films made them less attractive than other polymers. Poly(4-methylstyrene) has been explored as a possible polarizable gate insulator [48]. 

Wallace, R. and WiUc, G., High-k gate dielectric materials, MRS Bull. March 2002, 192-197, 2002. 

Also poly(chloro-/7-xylylene) (parylene-C) has been used as a gate dielectric material for transistors [42]. The devices exhibit positive bias shifts with negative DC gate-source voltages. No hysteresis was observed in the transfer characteristics for the devices. This tendency was enhanced with increasing annealing temperatures. 

Many materials systems are currently under consideration as potential replacements for Si02 as the gate dielectric material for sub-0.l-ftm CMOS technology. A systematic consideration of the required properties of gate dielectrics indicates that the key guidelines for selecting an alternative gate dielectric are (a) permittivity, band... 

Iwai H et al. (2002) Advanced gate dielectric materials for sub-100 nm CMOS. Tech Digest Int Electron Devices Meeting (IEEE). 

Bartic C, Jansen H, CampiteUi A, Borghs S (2002) Ta205 as gate dielectric material for low-voltage organic thin-film transistors. Org Electron 3 65-72... 

Another key issue for ZnO TFTs is the selection of the gate insulator. Various gate dielectric materials have been tested for ZnO-based TFTs, such as Si02 [162], Hf02 [169], PbZrTiO [185], ZnMgO [186], and Y2O3 [184]. As an example, TTFTs with transparent oxide semiconductor ZnO serving as the electron channel and... 

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