Field effect transistor with thin AlOxNy film as gate dielectric

2020 ◽  
Vol 37 (2) ◽  
pp. 103-107
Author(s):  
Piotr Firek ◽  
Jakub Szarafiński ◽  
Grzegorz Głuszko ◽  
Jan Szmidt

Purpose The purpose of this study is to directly measure and determine the Si/SiO2/AlOxNy interface state density on metal insulator semiconductor field effect transistor (MISFET) structures. The primary advantage of using aluminum oxynitride (AlOxNy) is the perfectly controlled variability of the properties of these layers depending on their stoichiometry, which can be easily controlled by the parameters of the magnetron sputtering process. Therefore, a continuous spectrum of properties can be achieved from the specific values for oxide to the specific ones for nitride, thus opening a wide range of applications in high power, high temperature and high frequency electronics, optics and sensors and even acoustic devices. Design/methodology/approach The basic subject of this study is n-channel transistors manufactured using silicon with 50-nm-thick AlOxNy films deposited on a silicon dioxide buffer layer via magnetron sputtering in which the gate dielectric was etched with wet solutions and/or dry plasma mixtures. Furthermore, the output, transfer and charge pumping (CP) characteristics were measured and compared for all modifications of the etching process. Findings An electrical measurement of MISFETs with AlOxNy gate dielectrics was conducted to plot the current-voltage and CP characteristics and examine the influence of the etching method on MISFET parameters. Originality/value In this report, a flat band and threshold voltage and the density of interface traps were determined to evaluate and improve an AlOxNy-based MISFET performance toward highly sensitive field effect transistors for hydrogen detection by applying a Pd-based nanocrystalline layer. The sensitivity of the detectors was highly correlated with the quality of the etching process of the gate dielectrics.

2019 ◽  
Vol 36 (3) ◽  
pp. 109-113
Author(s):  
Piotr Firek ◽  
Bartłomiej Stonio

Purpose The purpose of this paper is to present the influence of gate dielectric etching on obtained MISFET (metal insulator semiconductor field effect transistor) structures. Because of its properties, aluminum nitride (AlN) layers can be successfully used in a large area of applications. In addition, AIN has a wide bandgap (6.2eV) and high thermal conductivity (3.2 W/cm * K). Its melting temperature is greater than 2,000°C. The relative permittivity is about 9. All these features (especially high power, high temperature and high-frequency) make AlN a useful material in the fields of electronic, optical and acoustic applications. Design/methodology/approach To fabricate n-channel transistors, silicon technology was used. The 50-nm thick AlN films were deposited using the magnetron sputtering. After preparation of SiO2/AlN stack as the gate dielectric, the optimization processes of dry etching in plasma environment by Taguchi method were realized. In the next step, three methods of AlN etching were selected and used to MISFET device fabrication. Atomic force microscopy and scanning electron microscopy allowed to surfacing of the state observation after etching process. The current–voltage (I–V) output and transfer characteristics of structures with modified etch technology were measured. Keithley SMU 236/237/238 measurement set was used. Findings In this research work, a method of AlN etching in a field effect transistor technology was developed and improved. Current−voltage characteristics of obtained MISFET structures were measured and compared. Influence of etching procedure on transistors properties was examined. Originality/value The obtained results allow improving the MISFET technology based on AlN film as a gate dielectric. The complete research work will allow using the developed technologies to implement in highly sensitive ion-sensitive field effect transistor (ISFET) structures in the future. The improvement of the etching element in the technology strongly influences the detection capabilities and operating range of the transistor.


2021 ◽  
Vol 16 (12) ◽  
pp. P12034
Author(s):  
S. Hu ◽  
Y. Jia

Abstract The solution-gate graphene field effect transistor (Sg-GFET), as a popular sensing platform, its applications are still hindered by the deficiency in all-solid-state, due to the dependence on liquid-state gate-dielectric. Inspired by DNA hydrogel which can provide microporous architecture to accommodate the fluidic analyte, moreover, its combination with graphene is believed to foster electron transport in the field of electrochemistry. We are interested to take advantage of DNA hydrogel's solid-state and capability for holding solution, and investigate whether it can replace the traditional solution. So pure DNA hydrogel, their complexes with GO (GO/DNA hydrogel) and RGO (RGO/DNA hydrogel) are studied herein. Their micro-porous 3D morphologies are demonstrated, their influences on the electrical characteristics of GFETs are carefully examined and proved to be able to maintain the typical bipolarity of Sg-GFET, firstly. Then, pure DNA hydrogel and GO/DNA hydrogel are selected as the optimized gate-dielectrics, because of their renewability after dehydration. Furthermore, by using aptamer-based heavy metal ions (Pb2+ and Hg2+) detections as proof-of-concept, the strategies for building the sensing platform based on the optimized hydrogel dielectric-gated GFETs are studied. It is found, for the purpose of substituting fluidic dielectric in traditional Sg-GFET, the scheme of directly mounting aptamer on graphene channel and coating pure DNA hydrogel on it is demonstrated to be better than the strategies of using GO/DNA hydrogel and hybriding aptamer probes in hydrogel scaffold. It is explained according to surface charge sensing mechanism. At last, the performances of the sensing platform based on the proposed DNA hydrogel gated GFETs are testified by the detections and selectivity examinations for Pb2+ and Hg2+. Conclusively, pure DNA hydrogel is expected to be a promising candidate in the future all-solid-state Sg-GFET.


Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 680 ◽  
Author(s):  
Cao-An Vu ◽  
Wen-Yih Chen

Aptamers, in sensing technology, are famous for their role as receptors in versatile applications due to their high specificity and selectivity to a wide range of targets including proteins, small molecules, oligonucleotides, metal ions, viruses, and cells. The outburst of field-effect transistors provides a label-free detection and ultra-sensitive technique with significantly improved results in terms of detection of substances. However, their combination in this field is challenged by several factors. Recent advances in the discovery of aptamers and studies of Field-Effect Transistor (FET) aptasensors overcome these limitations and potentially expand the dominance of aptamers in the biosensor market.


2016 ◽  
Vol 60 (1) ◽  
pp. 81-90 ◽  
Author(s):  
Vivek Pachauri ◽  
Sven Ingebrandt

Biologically sensitive field-effect transistors (BioFETs) are one of the most abundant classes of electronic sensors for biomolecular detection. Most of the time these sensors are realized as classical ion-sensitive field-effect transistors (ISFETs) having non-metallized gate dielectrics facing an electrolyte solution. In ISFETs, a semiconductor material is used as the active transducer element covered by a gate dielectric layer which is electronically sensitive to the (bio-)chemical changes that occur on its surface. This review will provide a brief overview of the history of ISFET biosensors with general operation concepts and sensing mechanisms. We also discuss silicon nanowire-based ISFETs (SiNW FETs) as the modern nanoscale version of classical ISFETs, as well as strategies to functionalize them with biologically sensitive layers. We include in our discussion other ISFET types based on nanomaterials such as carbon nanotubes, metal oxides and so on. The latest examples of highly sensitive label-free detection of deoxyribonucleic acid (DNA) molecules using SiNW FETs and single-cell recordings for drug screening and other applications of ISFETs will be highlighted. Finally, we suggest new device platforms and newly developed, miniaturized read-out tools with multichannel potentiometric and impedimetric measurement capabilities for future biomedical applications.


MRS Advances ◽  
2017 ◽  
Vol 2 (23) ◽  
pp. 1249-1257 ◽  
Author(s):  
F. Michael Sawatzki ◽  
Alrun A. Hauke ◽  
Duy Hai Doan ◽  
Peter Formanek ◽  
Daniel Kasemann ◽  
...  

ABSTRACTTo benefit from the many advantages of organic semiconductors like flexibility, transparency, and small thickness, electronic devices should be entirely made from organic materials. This means, additionally to organic LEDs, organic solar cells, and organic sensors, we need organic transistors to amplify, process, and control signals and electrical power. The standard lateral organic field effect transistor (OFET) does not offer the necessary performance for many of these applications. One promising candidate for solving this problem is the vertical organic field effect transistor (VOFET). In addition to the altered structure of the electrodes, the VOFET has one additional part compared to the OFET – the source-insulator. However, the influence of the used material, the size, and geometry of this insulator on the behavior of the transistor has not yet been examined. We investigate key-parameters of the VOFET with different source insulator materials and geometries. We also present transmission electron microscopy (TEM) images of the edge area. Additionally, we investigate the charge transport in such devices using drift-diffusion simulations and the concept of a vertical organic light emitting transistor (VOLET). The VOLET is a VOFET with an embedded OLED. It allows the tracking of the local current density by measuring the light intensity distribution.We show that the insulator material and thickness only have a small influence on the performance, while there is a strong impact by the insulator geometry – mainly the overlap of the insulator into the channel. By tuning this overlap, on/off-ratios of 9x105 without contact doping are possible.


2021 ◽  
Author(s):  
Suman Yadav ◽  
Shivani Sharma ◽  
Satinder K Sharma ◽  
Chullikkattil P. Pradeep

Solution-processable organic semiconductors capable of functioning at low operating voltages (~5 V) are in demand for organic field-effect transistor (OFET) applications. Exploration of new classes of compounds as organic thin-film...


Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3735 ◽  
Author(s):  
Kęstutis Ikamas ◽  
Ignas Nevinskas ◽  
Arūnas Krotkus ◽  
Alvydas Lisauskas

We demonstrate that the rectifying field effect transistor, biased to the subthreshold regime, in a large signal regime exhibits a super-linear response to the incident terahertz (THz) power. This phenomenon can be exploited in a variety of experiments which exploit a nonlinear response, such as nonlinear autocorrelation measurements, for direct assessment of intrinsic response time using a pump-probe configuration or for indirect calibration of the oscillating voltage amplitude, which is delivered to the device. For these purposes, we employ a broadband bow-tie antenna coupled Si CMOS field-effect-transistor-based THz detector (TeraFET) in a nonlinear autocorrelation experiment performed with picoseconds-scale pulsed THz radiation. We have found that, in a wide range of gate bias (above the threshold voltage V th = 445 mV), the detected signal follows linearly to the emitted THz power. For gate bias below the threshold voltage (at 350 mV and below), the detected signal increases in a super-linear manner. A combination of these response regimes allows for performing nonlinear autocorrelation measurements with a single device and avoiding cryogenic cooling.


2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Yi Lan ◽  
Sidra Farid ◽  
Xenia Meshik ◽  
Ke Xu ◽  
Min Choi ◽  
...  

DNA aptamers have the ability to bind to target molecules with high selectivity and therefore have a wide range of clinical applications. Herein, a graphene substrate functionalized with a DNA aptamer is used to sense immunoglobulin E. The graphene serves as the conductive substrate in this field-effect-transistor-like (FET-like) structure. A voltage probe in an electrolyte is used to sense the presence of IgE as a result of the changes in the charge distribution that occur when an IgE molecule binds to the IgE DNA-based aptamer. Because IgE is an antibody associated with allergic reactions and immune deficiency-related diseases, its detection is of utmost importance for biomedical applications.


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