Effects Of Channel Thickness Research Articles

Simulation on the Effect of Channel Thickness on the Performance of Multi-Bridge Channel Field-Effect Transistor

A Multi-Bridge Channel Field-Effect Transistor (MBCFET) structure has been designed and simulated to characterize its electrical performance. An MBCFET is a device designed to bridge single-channel FETs, allowing more flexibility with signal routing and power management in complex designs. However, MBCFET suffers from Short Channel Effects which degrade its performance. Channel thickness is another important parameter that affect the performance of MBCFETs. Thus, the impact of channel thickness variation on MBCFET performance is investigated in this project. The electrical characteristic of MBCFET such as its threshold voltage (Vth), subthreshold swing (SS), on-state current (Ion), and off-state current (Ioff) were obtained and analyzed by using the TCAD simulation tool. Comparing the simulation results to published results indicated that the difference between the results was less than 5% for various parameters. The second part of the simulation work shows that as the channel thickness of an MBCFET increases, Vth decreases, Ion increases, and SS decreases. However, when the channel thickness is too thin, SS increases significantly, which leads to the device consuming higher power with lower performance.

Effect of channel thickness on radiation hardness of solution-processed oxide thin film transistors

The electrical properties of a-ZITO TFTs with different channel thicknesses were characterized under proton irradiation with electrical stress. The device measurements showed stronger radiation-tolerance of oxide TFTs with smaller channel thickness.

Effects of Channel Thickness on Electrical Performance and Stability of High-Performance InSnO Thin-Film Transistors

InSnO (ITO) thin-film transistors (TFTs) attract much attention in fields of displays and low-cost integrated circuits (IC). In the present work, we demonstrate the high-performance, robust ITO TFTs that fabricated at process temperature no higher than 100 °C. The influences of channel thickness (tITO, respectively, 6, 9, 12, and 15 nm) on device performance and positive bias stress (PBS) stability of the ITO TFTs are examined. We found that content of oxygen defects positively correlates with tITO, leading to increases of both trap states as well as carrier concentration and synthetically determining electrical properties of the ITO TFTs. Interestingly, the ITO TFTs with a tITO of 9 nm exhibit the best performance and PBS stability, and typical electrical properties include a field-effect mobility (µFE) of 37.69 cm2/Vs, a Von of −2.3 V, a SS of 167.49 mV/decade, and an on–off current ratio over 107. This work paves the way for practical application of the ITO TFTs.

Effect of channel thickness on noise in organic electrochemical transistors

Organic electrochemical transistors (OECTs) have been widely used as transducers in electrophysiology and other biosensing applications. Their identifying characteristic is a transconductance that increases with channel thickness, and this provides a facile mechanism to achieve high signal amplification. However, little is known about their noise behavior. Here, we investigate noise and extract metrics for the signal-to-noise ratio and limit of detection in OECTs with different channel thicknesses. These metrics are shown to improve as the channel thickness increases, demonstrating that OECTs can be easily optimized to show not only high amplification, but also low noise.

Effect of channel thickness on the electrical performance and the stability of amorphous SiZnSnO thin film transistor

The electrical performance and the stability of amorphous SiZnSnO (a-SZTO) thin film transistors (TFTs) were investigated depending on the channel thickness. The channel thickness was changed from 27 nm to 108 nm, systematically. As the channel thickness increased, the threshold voltage (VTH) of a-SZTO shifted to the positive direction, from 2.13 to 4.59 V. The negative bias temperature stress test (NBTS) was measured at −20 V for 120 min to determine the stability of a-SZTO TFTs at 60 °C. The ΔVTH was changed only 2.02 V at 27 nm because of less total trap density in the channel layer. The mechanism of stability change depending on the thickness is explained. Transmission line method (TLM) was also used to find the relation between the total resistance (RTotal) and the channel thickness. As increasing the channel thickness, the contact resistance (RC) increased and sheet resistance (Rsh) decreased. It must be considered the channel thickness of a-SZTO channel layer for the electrical properties and stability. Finally, we made the depletion load type inverter using two transistors of different channel thickness. The achieved voltage gain of the inverter is 21.962 V/V at the VDD = 11 V.

Preferential Paths of Air-water Two-phase Flow in Porous Structures with Special Consideration of Channel Thickness Effects

Accurate understanding and predicting the flow paths of immiscible two-phase flow in rocky porous structures are of critical importance for the evaluation of oil or gas recovery and prediction of rock slides caused by gas-liquid flow. A 2D phase field model was established for compressible air-water two-phase flow in heterogenous porous structures. The dynamic characteristics of air-water two-phase interface and preferential paths in porous structures were simulated. The factors affecting the path selection of two-phase flow in porous structures were analyzed. Transparent physical models of complex porous structures were prepared using 3D printing technology. Tracer dye was used to visually observe the flow characteristics and path selection in air-water two-phase displacement experiments. The experimental observations agree with the numerical results used to validate the accuracy of phase field model. The effects of channel thickness on the air-water two-phase flow behavior and paths in porous structures were also analyzed. The results indicate that thick channels can induce secondary air flow paths due to the increase in flow resistance; consequently, the flow distribution is different from that in narrow channels. This study provides a new reference for quantitatively analyzing multi-phase flow and predicting the preferential paths of immiscible fluids in porous structures.

Effects of channel thickness on structure and transport properties of AlGaN/InGaN heterostructures grown by pulsed metal organic chemical vapor deposition

High-quality AlGaN/InGaN heterostructures are grown and the effects of InGaN channel thickness on the structure and transport properties are investigated. With the increase of InGaN channel thickness from 7 nm to 28 nm, the two-dimensional electron gas density decreases continuously, while the mobility shows a trend of increasing at first, and then decreasing. The optimum thickness of 21 nm is obtained for the In0.05Ga0.95N channel, achieving a high electron mobility of 1712 cm2/V, which indicates the huge potential for InGaN channel heterostructures in high-frequency and high-power applications. The variation in transport properties is studied by analyzing the structure formation, material quality, and interface characteristic in detail. The results are not only beneficial for the further study of the InGaN channel heterostructures, but also instructive for the other inserted channel system.

Effects of channel thickness on oxide thin film transistor with double-stacked channel layer

To improve the field effect mobility and control the threshold voltage (V th ) of oxide thin film transistors (TFTs), we fabricated the oxide TFTs with double-stacked channel layers which consist of thick Zn-Sn-O (ZTO) and very thin In-Zn-O (IZO) layers. We investigated the effects of the thickness of thin conductive layer and the conductivity of thick layer on oxide TFTs with doublestacked channel layer. When we changed the thickness of thin conductive IZO channel layer, the resistivity values were changed. This resistivity of thin channel layer affected on the saturation field effect mobility and the off current of TFTs. In case of the thick ZTO channel layer which was deposited by sputtering in Ar: O2 = 10: 1, the device showed better performances than that which was deposited in Ar: O2 = 1: 1. Our TFTs showed high mobility (μ FE ) of ~ 40.7 cm2/Vs and V th of ~ 4.3 V. We assumed that high mobility and the controlled V th were caused by thin conductive IZO layer and thick stable ZTO layer. Therefore, this double-stacked channel structure can be very promising way to improve the electrical characteristics of various oxide thin film transistors.

Paper No P20: Effects of the Channel Thickness on Characteristics of Ga‐Doped Zinc Oxide Thin‐Film Transistors Fabricated on Glass

AbstractIn this paper, high‐performance fully transparent bottom‐gate type Ga‐doped zinc oxide thin‐film transistors (GZO TFTs) have been successfully fabricated on glass substrate. The effects of channel thickness on the electrical performances of GZO TFTs are researched. We study to improve the performance of bottom gate Ga‐doped Zinc Oxide Thin Film Transistors by optimizing the active layer process. Optimized TFTs exhibit excellent electrical properties, with high Ion/Ioff current ratio of 1.3 × 109, saturation mobility (μsat) of 99 cm2/Vs, subthreshold swing (SS) of 77mV/decade and threshold voltage (Vth) of 2.2 V. The variation trend of Ion/Ioff, μsat, SS, and Vth against channel thickness is analyzed in detail. The experimental results suggest that the performance of GZO TFT can be improved effectively by optimum channel thickness.

Effect of Channel Thickness and Doping Concentration on Sub-Threshold Performance of Graded Channel and Gate Stack DG MOSFETs

Effect of Channel Thickness and Doping Concentration on Sub-Threshold Performance of Graded Channel and Gate Stack DG MOSFETs

Effect of channel thickness, electrolyte ions, and dissolved oxygen on the performance of organic electrochemical transistors

We investigated the device characteristics of organic electrochemical transistors based on thin films of poly(3,4-ethylenedioxythiophene) doped with poly(styrene-sulfonate). We employed various channel thicknesses and two different electrolytes: the micelle forming surfactant cetyltrimethyl ammonium bromide (CTAB) and NaCl. The highest ON/OFF ratios were achieved at low film thicknesses using CTAB as the electrolyte. Cyclic voltammetry suggests that a redox reaction between oxygen dissolved in the electrolytes and PEDOT:PSS leads to low ON/OFF ratios when NaCl is used as the electrolyte. Electrochemical impedance spectroscopy reveals that doping/dedoping of the channel becomes slower at high film thickness and in the presence of bulky ions.

On the Ballistic Performance of InGaSb XOI FET: Impact of Channel Thickness and Interface States

Here, we report the effect of channel thickness on the performance of a InGaSb-on-insulator FET with 15-nm gate length. The ballistic current-voltage characteristic is computed by nonequilibrium Green’s function method using thickness-dependent effective mass, which is extracted from tight binding dispersion. Simulation result reveals that the threshold voltage and subthreshold slope decrease with decreasing channel thickness. Nearly three times enhancement in the ON-state current is observed for 3 nm compared with a 5-nm channel when the OFF-state current is made equal in each case by tuning the gate metal work function (WF). The drain-induced barrier lowering is found to decrease with decreasing channel thickness. However, interface states and roughness greatly affect the performance of such ultrathin-body device. Nevertheless, impact of interface states can be compensated by engineering the gate metal WF.

Effects of channel thickness on characteristics of HZO‐TFTs fabricated at low temperature

The channel process to further improve the performance of bottom gate hafnium-doped zinc oxide (HZO) thin-film transistors (TFTs) is optimised. The effects of channel thickness on the electrical performances of HZO TFTs is studied. The results show that the extracted saturation mobility increases first and then decreases with the increase of HZO film thickness, reaching maximum when the channel thickness is optimum. The dependence of the optimum thickness on channel length is studied and it is found that optimum thickness increases with the increase of channel length.

Effect of channel thickness on the field effect mobility of ZnO-TFT fabricated by sol gel process

In this study, bottom-gate structured ZnO TFTs were fabricated on pSi/SiO2 substrate. ZnO active layers with different thickness were deposited by using sol gel spin coating method and the electrical performances of the obtained TFTs were investigated regarding the thickness of the channel layer. The effects of channel thickness on the structural and morphological properties of ZnO were examined. The mobility values of TFTs were significantly improved by increasing the thickness of active channel layer and the highest mobility of ZnO TFTs was obtained by 1.09cm2/Vs for 140nm layer. ZnO TFTs showed a high off-current and this current increased as the channel thickness increased.

Effect of channel thickness on electrical performance of amorphous IGZO thin-film transistor with atomic layer deposited alumina oxide dielectric

We have investigated the electrical performance of amorphous indium–gallium–zinc oxide (α-IGZO) thin-film transistors with various channel thicknesses. It is observed that when the α-IGZO thickness increases, the threshold voltage decreases as reported at other researches. The intrinsic field-effect mobility as high as 11.1 cm2/Vs and sub threshold slope as low as ∼0.2 V/decade are independent on the thickness of α-IGZO channel, which indicate the excellent interface between α-IGZO and atomic layer deposited Al2O3 dielectric even for the case with α-IGZO thickness as thin as 10 nm. However, the source and drain series resistances increased with increasing of α-IGZO channel thickness, which results in the apparent field-effect mobility decreasing. The threshold voltage shift (ΔVth) under negative bias stress (NBS) and negative bias illumination stress (NBIS) were investigated, also. The hump-effect in the sub threshold region under NBS and threshold voltage shift to negative position under NBIS were enhanced with decreasing of α-IGZO channel thickness, owing to the enhancement of vertical electrical field in channel.

Active Layer Thickness Effects on the On-State Current and Pulse Measurement at Room Temperature on Deposited Zinc Oxide Thin-Film Transistors

This study reports on the fabrication of thin-film transistors (TFTs) with transparent zinc oxide (ZnO) semiconductors serving as the active channel and silicon dioxide (SiO2) serving as the gate insulator. The ZnO films were deposited by radiofrequency magnetron sputtering at room temperature. Moreover, the effects of channel thickness on the structural and pulse current–voltage characteristics of ZnO TFTs using a bottom gate configuration were investigated. As the channel thickness increased, the crystalline quality and the channel conductance were enhanced. The electrical characteristics of TFTs exhibited field-effect mobilities of 8.36 cm2/Vs to 16.40 cm2/Vs and on-to-off current ratios of 108 to 107 for ZnO layer thickness of 45 nm and 70 nm, respectively. The threshold voltage was in the range of 10 V to 31 V for ZnO layer thicknesses from 35 nm to 70 nm, respectively. The low deposition and processing temperatures make these TFTs suitable for fabrication on flexible substrates.

Effect of channel thickness on density of states in amorphous InGaZnO thin film transistor

We report on the origin of threshold voltage shift with the thickness of amorphous InGaZnO channel layer deposited by rf magnetron sputter at room temperature, using density of states extracted from multi frequency method and falling rates of activation energy, which of trends are entirely consistent each other in respect of the reduction of total traps with increasing the channel thickness. Furthermore, we shows that the behavior of ΔVth under the positive gate bias stress and thermal stress can be explained by charge trapping mechanism based on total trap variation.

Unsteady conjugate problem of a dissipative fluid in a horizontal channel with a periodic variation temperature

The unsteady two-dimensional transient heat transfer problem referring to a fully laminar flow developing in a parallel-plane channel exposed to a periodic variation surface temperature with distance is numerically studied. The effects of channel thickness, Peclet number, wall-to-fluid conductivity ratio, thermal diffusivity ratio, angular frequency and the viscous dissipation parameter are determined in the solutions. The non-linear equations are discretized by means an implicit finite difference scheme and the electric analogy to the resulting system is applied to convert these equations into a network-electrical model that was solved using a computer code (electric circuits simulator). In this scheme, only spatial discretization is necessary, while time remains as a real continuous variable, and its programming does not require manipulation of the sophisticated mathematical software that is inherent in other numerical methods. The network simulation method, which satisfies the conservation law for the heat flux variable and the uniqueness law for temperature, also permits the direct visualization of the local and/or integrated transport variables at any point or section of the medium.

Pre-apoptotic sub-population cell sorting from diosgenin apoptosis induced 1547 cells by Sedimentation Field-Flow Fractionation: The effect of channel thickness on sorting performance

Apoptosis is one of the most important phenomena in cell biology. Pre-apoptotic cells, defined as cells engaged in early stages of apoptosis, could be used as a cellular tool to study apoptosis pathways. The human 1547 osteosarcoma cell line and diosgenin (a plant steroid) association was selected as an in vitro cellular apoptosis model. In a previous study, using this model, we demonstrated that SdFFF monitored apoptosis induction as early as 6 h after incubation. In this study, we investigated the capacity of Sedimentation Field-Flow Fractionation (SdFFF) to sort an enriched population of pre-apoptotic cells from 1547 cells incubated for 6 h with 40 μM diosgenin. In that way, two different separation devices which differed especially in channel thickness, 125 and 175 μm, were used and compared. Results showed, for the first time, that SdFFF is an effective method to obtain an enriched pre-apoptotic sub-population. These results suggest, as a new application, that SdFFF could be an included tool in the study of apoptotic mechanisms or the kinetic action of apoptotic drugs.

Channel thickness dependence of breakdown dynamic in InP-based lattice-matched HEMTs

We have investigated, by using Monte Carlo simulations, the effects of channel thickness on the breakdown dynamics in InP-based lattice-matched HEMTs (LM-HEMTs). Breakdown is due to the parasitic bipolar action of holes generated by impact ionization and accumulated in the low electric field regions near the source. Our results show that channel shrinking results in an increase in time-to-breakdown values due to holes real-space-transfer effects occurring in thin channel devices. The breakdown behavior of thin-channel devices (channel thickness /spl les/20 nm) is dominated by the accumulation of holes in the InAlAs buffer layer; in thick-channel devices breakdown is due to the parasitic bipolar action of holes accumulating in the InGaAs channel. These results suggest a frequency dependence of breakdown which can be relevant for power rf device applications and/or in the study of device survivability to rf overstress.