Planar transistors field-effect transistor

Short intramolecular contacts between chalcogens and other chalcogens or other heteroatoms have been shown to influence molecular geometry, particularly planarity, in many structures of electroactive materials. Hence the position of the chalcogen atom in the material can profoundly affect its properties. For example Crouch et al 2 report the X-ray crystal structure of compound 24 (Figure 10), a candidate for an organic field-effect transistor, showing the effect of intramolecular S- F close contacts (in tandem with H F contacts) on the planarity of the molecule in the solid state. Note also the... 

More recently, the 5-5 heterocyclic system has found application in the preparation of -type organic field effect transistors, which are currently receiving much attention for applications such as flexible displays, low-cost electronic papers, and smart memory-sensor elements. The most recent examples are molecules prepared by Yamashita, who has prepared the planar, perfluorinated thiazolothiazole molecules 169-171 to this end <2004CL1170, 2005JA5336, 2004JMC1787>. 

A plurality of thin film field effect transistors 11 are deposited onto a substrate 12. Each of the transistors has a source electrode 13, a drain electrode 14 and a gate electrode 15. Source lines 17 link the source electrodes in each row of the transistors and drain lines 18 link the drain electrodes in each column of the transistors. The source lines and drain lines are electrically isolated by a planarization layer 19. A mercury cadmium telluride layer 20 is deposited onto the planarization layer followed by a top electrode layer 23. The gate electrodes are connected with the mercury cadmium telluride layer by connectors 21. A cross-section of the imager is shown below. 

Our choice for an Ion Sensitive Field Effect Transistor (ISFET) as a transducing element was based on the fact that the SiO surface contains reactive SiOH groups for the covalent attachment of organic molecules and polymers. In addition the FET has fast response times and can be made very small with existing planar IC technology. FIGURE 1... 

Ba " ", Cs, NH4", Ag" ") and anions (NOi j Cl , HCOi ). Solid-state ISEs (coated wire electrodes) have also been developed in which the sensitive membrane is coated directly onto a metal wire, usually a silver-silver halide. While these have the advantage of being small and easy to fabricate, they have been noted for their unpredictable properties and suffer from lifetime and stability problems. More sophisticated approaches involve the use of semiconductor planar fabrication technologies to deposit ion-sensitive layers onto semiconductor substrates to produce ion-selective field-effect transistors. These are conceptually very attractive but it has proven very difficult to produce devices as good as the equivalent ISE. 

As an example the limitations in the commonly used planar technology are related to difficulties in making field effect transistors (FET), with low... 

One of the early hopes was that the technique could be used to create ultrathin insulating layers for field effect transistors and other electronic devices. This application is, however, bedeviled by the presence of very small defects (pinholes) in the films. These defects can be obviated by using a material whose transition temperature is well below room temperature (at which, it is assumed, fabrication takes place), such as the phospholipids found in nature as the main amphiphilic components of the ubiquitous bilayer lipid membrane that surrounds cells and their internal organelles, but these molecules are not very robust and would not have the longevity required in typical electronics applications. Another attempted application has been the creation of planar optical waveguides, but it turned out to... 

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