Biologically sensitive field-effect devices using polysilicon TFTs

The authors present a review of recent developments in the detection of biomolecular interactions with field-effect devices. Ion-sensitive field-effect transistors (ISFETs) and enzyme field-effect transistors (EnFETs), based on polycrystalline silicon (poly-Si) TFTs, are discussed. Label-free electrical detection of DNA hybridization has been achieved by a new method, by using MOS capacitors or poly-Si TFTs. In principle, the method can be extended to other chemical or biochemical systems, such as proteins and cells.

A field effect transistor using highly nitrogen-doped CVD diamond for power device applications

A new idea of power device, which contains highly nitrogen-doped CVD diamond and Schottky contact, is proposed to actualise a power device with diamond. Two-dimensional simulation is conducted using ISE TCAD device simulator. While comparably high current is obtained in a transient simulation as expected, this current does not contribute to the drain-source current because of the symmetry of the device. Using an asymmetric structure or bias conditions, the device has high potential as an electric device for extremely high power, high frequency and high temperature. © 2003 Elsevier Science B.V. All rights reserved.

Direct growth of horizontally aligned carbon nanotubes between electrodes and its application to field-effect transistors

This paper presents direct growth of horizontally aligned carbon nanotubes (CNTs) between two predefined various inter-spacing up to tens of microns of electrodes (pads) and its use as CNT field-effect transistors (CNT-FETs). The catalytic metals were prepared, consisting of iron (Fe), aluminum (Al) and platinum (Pt) triple layers, on the thermal silicon oxide substrate (Pt/Al/Fe/SiO2). Scanning electron microscopy measurements of CNT-FETs from the as-grown samples showed that over 80% of the nanotubes are grown across the catalytic electrodes. Moreover, the number of CNTs across the catalytic electrodes is roughly controllable by adjusting the growth condition. The Al, as the upper layer on Fe electrode, not only plays a role as a barrier to prevent vertical growth but also serves as a porous medium that helps in forming smaller nano-sized Fe particles which would be necessary for lateral growth of CNTs. Back-gate field effect transistors were demonstrated with the laterally aligned CNTs. The on/off ratios in all the measured devices are lower than 100 due to the drain leakage current. ©2010 IEEE.

Trapped charge dynamics in a sol-gel based TiO(2) high- k gate dielectric silicon metal-oxide-semiconductor field effect transistor.

We have studied the response of a sol-gel based TiO(2), high k dielectric field effect transistor structure to microwave radiation. Under fixed bias conditions the transistor shows frequency dependent current fluctuations when exposed to continuous wave microwave radiation. Some of these fluctuations take the form of high Q resonances. The time dependent characteristics of these responses were studied by modulating the microwaves with a pulse signal. The measurements show that there is a shift in the centre frequency of these high Q resonances when the pulse time is varied. The measured lifetime of these resonances is high enough to be useful for non-classical information processing.