[en] The operation principle of a semiconductor nanowire (NW) ion-sensitive field effect transistor (ISFET), denoted for pH sensing, is studied within the framework of this work. The physical processes in the system are mathematically modelled and presented in details. The dependences of the NW ISFET current-pH characteristics on NW geometrical and physical parameters are analyzed. The plots of the ISFET sensitivity versus pH at different NW radii, the thicknesses of the oxide layer, and the NW doping densities are presented. The obtained results are in qualitative agreement with the experimental data

[en] Semiconductor devices are prepared by forming a pattern of resist material on a substrate, using the pattern as a mask to form doping regions and forming the latter by ion implantation. (U.K.)

[en] In this paper, the impact of correlation between two line-edge roughnesses (LERs) on electronic transport in armchair graphene nanoribbons (AGNRs) is investigated, employing an atomistic model based on the non-equilibrium Greens function formalism. For demonstrating the influence of this correlation, crucial transport properties like mean free path and localization lengths corresponding to different sets of roughnesses and geometrical parameters are extracted. The results indicate the substantial role of the degree of cross-correlation in transport characteristics. Besides, for showing its importance in practice, some parameters in an AGNR-based field effect transistor relating to diverse correlations are provided. Additionally, an analytical compact model is developed to formulate conductance as a function of cross-correlation coefficient. The presented results offer novel insights into electronic transport in GNRs casting light on how the correlation of LERs should be regarded as the decisive factor in choosing an experimental approach for fabrication of GNRs. (paper)

[en] A novel n-type junctionless field-effect transistor (JLFET) with a step-gate-oxide (SGO) structure is proposed to suppress the gate-induced drain leakage (GIDL) effect and off-state current I _off. Introducing a 6-nm-thick tunnel-gate-oxide and maintaining 3-nm-thick control-gate-oxide, lateral band-to-band tunneling (L-BTBT) width is enlarged and its tunneling probability is reduced at the channel--drain surface, leading the off-state current I _off to decrease finally. Also, the thicker tunnel-gate-oxide can reduce the influence on the total gate capacitance of JLFET, which could alleviate the capacitive load of the transistor in the circuit applications. Sentaurus simulation shows that I _off of the new optimized JLFET reduced significantly with little impaction on its on-state current I _on and threshold voltage V _TH becoming less, thus showing an improved I _on/I _off ratio (5 × 10⁴) and subthreshold swing (84 mV/dec), compared with the scenario of the normal JLFET. The influence of the thickness and length of SGO structure on the performance of JLFET are discussed in detail, which could provide useful instruction for the device design. (paper)

[en] Operations of arrayed ferroelectric (Fe)-NAND flash memory cells: erase, program and read were demonstrated for the first time using a small cell array of four word lines by two NAND strings. The memory cells and select-gate transistors were all n-channel Pt/SrBi₂Ta₂O₉/Hf-Al-O/Si ferroelectric-gate field effect transistors. The erase was performed by applying 10 µs wide 7 V pulses to n- and p-wells. The program was performed by applying 10 µs wide 7 V pulses to selected word lines. Accumulated read currents of 51 programmed patterns in the Fe-NAND flash memory cell array successfully showed distribution of the two distinguishable '0' and '1' states. The margin between the two states became wider by applying a verification technique in programming a cell out of the eight. Retention times of bit-line currents were obtained over 33 h for both the '0' and '1' states in a program pattern

[en] Si nanonets (SiNN, networks of randomly oriented Si nanowires) and multi-parallel silicon nanowires (MP-SiNW) were integrated into field effect transistor using standard and low cost microelectronic technologies. The SiNN field effect transistors exhibit high initial ON-state current (in the range of 10^–7 A), I_ON/I_OFF ratio up to 10⁴ and rather homogeneous transfer characteristics. In contrast, the MP-SiNW ones present smaller modulation between ON and OFF currents, higher I_OFF and more scattered electrical characteristics. In view of DNA hybridization detection, a simple and eco-friendly functionalization process with glycidyloxypropyltrimethoxysilane (GOPS) was used to covalently graft single strand DNA probes on both SiNN and MP-SiNW devices. Validated by fluorescence measurement, DNA hybridization leads to a systematic decrease of ON-state current of SiNN devices. In addition, SiNN-based sensors exhibit more homogeneous and reproducible current variation in response to DNA hybridization step as compared to MP-SiNW configuration. This result highlights the better sensing performances of SiNN FETs as compared to MP-SiNW ones and emphasizes the SiNN potential for label-free detection of DNA. (paper)

[en] Field effect transistors have been fabricated on high-purity germanium substrates using low-temperature technology. The aim of this work is to preserve the low density of trapping centers in high-quality starting material by low-temperature (< 350⁰C) processing. The use of germanium promises to eliminate some of the traps which cause generation-recombination noise in silicon field-effect transistors (FET's) at low temperatures. Typically, the transconductance (g/sub m/) in the germanium FET's is 10 mA/V and the gate leakage can be less than 10^-12 A. Present devices exhibit a large 1/f noise component and most of this noise must be eliminated if they are to be competitive with silicon FET's commonly used in high-resolution nuclear spectrometers

[en] The field-effect transistor (FET) noise properties of KP303G, KP307ZH, 2N4416, 2N4392 types are investigated. FETs of first three types are used in the charge-sensitive preamplifier circuits. It is shown that the least contribution to the noise by connecting up a preamplifier to detector has been obtained by using the 2N4392 FET switch. The preamplifier circuit involving such a FET is given. The obtained results can be applied in precision nuclear spectroscopy

[en] The dependence of ballistic electron current on Sn content, sidewall orientations, fin width, and uniaxial stress is theoretically studied for the GeSn fin field-effect transistors. Alloying Sn increases the direct Γ valley occupancy and enhances the injection velocity at virtual source node. (112^¯) sidewall gives the highest current enhancement due to the rapidly increasing Γ valley occupancy. The non-parabolicity of the Γ valley affects the occupancy significantly. However, uniaxial tensile stress and the shrinkage of fin width reduce the Γ valley occupancy, and the currents are enhanced by increasing occupancy of specific indirect L valleys with high injection velocity

[en] The advantages of organic field-effect transistors (OFETs), such as low cost, flexibility and large-area fabrication, have recently attracted much attention due to their electronic applications. Practical transistors require high mobility, large on/off ratio, low threshold voltage and high stability. Development of new organic semiconductors is key to achieving these parameters. Recently, organic semiconductors have been synthesized showing comparable mobilities to amorphous-silicon-based FETs. These materials make OFETs more attractive and their applications have been attempted. New organic semiconductors resulting in high-performance FET devices are described here and the relationship between transistor characteristics and chemical structure is discussed. (topical review)