Field effect

About: Field effect is a research topic. Over the lifetime, 4018 publications have been published within this topic receiving 92613 citations.

MOSFET with suppressed gate-edge fringing field effect

Abstract: A method of fabricating an integrated circuit with less susceptibility to gate-edge fringing field effect is disclosed. The transistor includes a low-k dielectric spacer and a high-k gate dielectric. The high-k gate dielectric can be tantalum pentaoxide or titanium dioxide. The process can be utilized for P-channel or N-channel metal oxide field semiconductor effect transistors (MOSFETs).

Modulating the charge-transfer enhancement in GERS using an electrical field under vacuum and an n/p-doping atmosphere.

Abstract: The modulation of charger-transfer (CT) enhancement in graphene-enhanced Raman scattering (GERS) by an electric field under different atmospheres is reported. The GERS spectra of cobalt phthalocyanine (CoPc) molecules were collected by in situ Raman measurements under ambient air, vacuum, NH3 atmosphere, and O2 atmosphere, in which the Fermi level of graphene was modulated by an electrical field effect (EFE). The Raman scattering intensities of adsorbed molecules can be tuned to be stronger or weaker as the graphene Fermi level down-shifts or up-shifts under electrical field modulation. However, the Raman intensity modulation in GERS is seriously influenced by the hysteresis effect in graphene EFE, which makes the modulation ability small and shows strong gate voltage sweep rate dependence in ambient air. Fortunately, the hysteresis effect in graphene EFE can be decreased by performing the measurement under vacuum conditions, and thus the Raman modulation ability in GERS can be increased. Furthermore, compared with the vacuum condition, the Raman modulation ability shows an increase under an NH3 atmosphere, while it shows a decrease under an O2 atmosphere, which is due to the different Fermi level modulation region in different atmospheres. More interestingly, this Raman intensity modulation in GERS shows a hysteresis-like behavior that is the same as the graphene Fermi level modulation under the EFE in a different atmosphere. All these observations suggest that the Raman enhancement in GERS occurs through a charge-transfer (CT) enhancement mechanism and the CT process can be modulated by the graphene EFE. This technique will benefit the study of the basic properties of both graphene and chemical enhancement mechanism in surface-enhanced Raman spectroscopy (SERS).

Air stable, high performance pentacene thin-film transistor fabricated on SiO2 gate insulator treated with β-phenethyltrichlorosilane

Abstract: A pentacene thin-film transistor (TFT) was fabricated on a SiO2 gate insulator treated with β-phenethyltrichlorosilane (β-PTS). Employing β-PTS for the surface treatment of SiO2, large grains were present in the initial stage of pentacene crystal growth. The field effect mobility was as high as 1.5cm2∕Vs and the on/off ratio was over 106. The surface treatment dramatically improved the stability in air of the pentacene-TFT’s electrical characteristics. A field effect mobility of over 1cm2∕Vs and on/off ratio of over 105 were maintained after scanning the gate voltage 2000 times in air. This result indicates that the surface treatment with β-PTS not only improved TFT performance but also significantly suppressed the device’s degradation.

Field-Effect Semiconductor Device

Abstract: A HEMT-type field-effect semiconductor device has a main semiconductor region comprising two layers of dissimilar materials such that a two-dimensional electron gas layer is generated along the heterojunction between the two layers. A source and a drain electrode are placed in spaced positions on a major surface of the main semiconductor region. Between these electrodes, a gate electrode is received in a recess in the major surface of the main semiconductor region via a p-type metal oxide semiconductor film whereby a depletion zone is normally created in the electron gas layer, with a minimum of turn-on resistance and gate leak current.

The effect of surface states and fixed charge on the field effect conductance of amorphous silicon

Abstract: We have developed a computer program to calculate the field effect conductance for an amorphous semiconductor including the effects of surface states and fixed charge at both surfaces of the thin semiconductor film. For undoped films with a bulk density of states of less than 1017 cm−3 eV−1, the space‐charge region extends to a depth of 0.5 μm. A complete description of the potential distribution in the semiconductor must include the contribution of surface charge from the surface opposite the gate electrode. This is of practical importance in thin film transistors, for example, where different transistor structures and processing of devices can affect the charge density of this surface.