Mohamad Faris Mohamad Fathil
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Preferred name
Mohamad Faris Mohamad Fathil
Official Name
Mohamad Faris, Mohamad Fathil
Alternative Name
Fathil, Mohamad Faris Mohamad
Fathil, Mohamad Faris Bin Mohamad
Main Affiliation
Scopus Author ID
56395434600
Researcher ID
U-3213-2019

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Effect of back gate biasing on silicon nanowire field effect transistor

2021-05-03 , Wan Amirah Basyarah Z.A. , Md Nor M.N. , Mohd Khairuddin Md Arshad , Mohamad Faris Mohamad Fathil , Azlan A.S. , Ibau C.

This work presents an experimental analysis of the substrate bias influence on the operation of Silicon Nanowire Field Effect Transistor (SiNW-FET). The device analysis has been performed by using atomic force microscope (AFM) and scanning electron microscope (SEM) to obtain the surface morphological characterization. Then, the electrical characterization was measured over a linear DC sweep, range from -1.5 V to 0.6 V with a step voltage of 0.01V and the variation on the substrate bias applied to the sample from -1V to 0V. As a result, the back gate was found to influence the conductivity of the nanowire with a higher than 0.79 V gate voltage to be applied. The device demonstrated a good behavior of p-type silicon nanowire field effect transistor and capable to operate as a biosensing device.

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Femtomolar Dengue Virus Type-2 DNA Detection in Back-gated Silicon Nanowire Field-effect Transistor Biosensor

2022-01-01 , Abidin W.A.B.Z. , Nor M.N.M. , Mohd Khairuddin Md Arshad , Mohamad Faris Mohamad Fathil , Nor Azizah Parmin , Sisin N.A.H.T. , Ibau C. , Azlan A.S.

Background: Dengue is known as the most severe arboviral infection in the world spread by Aedes aegypti. However, conventional and laboratory-based enzyme-linked immunosorbent as-says (ELISA) are the current approaches in detecting dengue virus (DENV), requiring skilled and well-trained personnel to operate. Therefore, the ultrasensitive and label-free technique of the Silicon Nanowire (SiNW) biosensor was chosen for rapid detection of DENV. Methods: In this study, a SiNW field-effect transistor (FET) biosensor integrated with a back-gate of the low-doped p-type Silicon-on-insulator (SOI) wafer was fabricated through conventional photo-lithography and Inductively Coupled Plasma – Reactive Ion Etching (ICP-RIE) for Dengue Virus type-2 (DENV-2) DNA detection. The morphological characteristics of back-gated SiNW-FET were examined using a field-emission scanning electron microscope supported by the elemental analysis via energy-dispersive X-ray spectroscopy. Results and Discussion: A complementary (target) single-stranded deoxyribonucleic acid (ssDNA) was recognized when the target DNA was hybridized with the probe DNA attached to SiNW surfaces. Based on the slope of the linear regression curve, the back-gated SiNW-FET biosensor demonstrated the sensitivity of 3.3 nAM-1 with a detection limit of 10 fM. Furthermore, the drain and back-gate voltages were also found to influence the SiNW conductance changed. Conclusion: Thus, the results obtained suggest that the back-gated SiNW-FET shows good stability in both biosensing applications and medical diagnosis throughout the conventional photolithography method.

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Lectin bioreceptor approach in capacitive biosensor for prostate-specific membrane antigen detection in diagnosing prostate cancer

2021-03-01 , Subramani I.G. , Ramzan Mat Ayub , Subash Chandra Bose Gopinath , Perumal V. , Mohamad Faris Mohamad Fathil , Mohd Khairuddin Md Arshad

This research reports a new approach with lectin-based capacitive non-faradaic biosensor for the detection of prostate-specific membrane antigen (PSMA) as a promising diagnostic marker for determining prostate cancer. PSMA expression is significantly higher in malign hyperplasia, thus can be effectively employed to discriminate other benign prostatic diseases. Herein, the aluminium interdigitated electrode was fabricated and modified by a linker, 2-mercaptoacetate to form the self-assembled monolayer. Gold nanoparticles were used as a signal amplifier and supported the conjugation of Concanavalin A, for efficient capacitive sensing of PSMA. Scanning electron microscope observation effectively captured the surface modification on the aluminium surface by revealing the specific adherence of gold nanoparticles with Concanavalin A. Moreover, the successful surface modification was further validated by atomic force microscopy, Fourier transforms infrared spectroscopy, and X-ray photoelectron spectroscopy. The interaction analysis of Concanavalin A with PSMA by capacitive non-faradaic measurement exhibited a linear detection range from 10 pM to 100 nM and attained the detection limit and sensitivity of 10 pM and 1.65 nF/pM respectively as the comparable performance to the current sensing strategies. Furthermore, the fabrication and quantification of PSMA as demonstrated here are relatively simple and can be employed for the straightforward detection of other biomarkers.

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ESD improvement in P-i-N diode through introducing a lighter and deeper anode junction

2017-07 , J. H. See , Mohd Khairuddin Md Arshad , Mohamad Faris Mohamad Fathil

Continuous and aggressive miniaturization in the electronic gadget size poses a challenge in solving Electrostatic Discharge (ESD) reliability performance. For diode devices, the shrinkage of the size leads to severe electrical field crowding effect which can cause a total device failure under high ESD surge. Therefore, in this paper, we present a better ESD performance characteristic which can be achieved by optimizing the profile of the P+ anode junction of P-i-N diode. The characteristics profile can be altered by lowering the dopant concentration and increasing the depth of the P-i-N diode junction. In this work, comprehensive device simulations, followed by simulation result validation at the wafer level were performed. The ESD surge test was performed and results showed that the changes of the P+ anode junction profile on the P-i-N power switching diode can achieve the sustainability of 1 kV ESD surge in the Human Body Model (HBM) and more than 400 V ESD surge in the Machine Model (MM).

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Field-Effect Transistor-based Biosensor Optimization: Single Versus Array Silicon Nanowires Configuration

2020-01-01 , Ong C.C. , Mohamad Faris Mohamad Fathil , Mohd Khairuddin Md Arshad , Mohammad Nuzaihan Md Nor , Ruslinda A. Rahim , Uda Hashim , Rafizatul Fitri Abdullah , Mohd Hazmi Mohd Ghazali , Tamjis N.

This paper demonstrated the effect of different number of silicon nanowire transducer channels, in other word single, double, and triple channels towards the performance of field-effect transistor-based biosensor through simulation tool. These silicon nanowire field-effect transistor biosensors were designed and simulated in device simulation modelling tool, Silvaco ATLAS with fixed length, width, and height of the silicon nanowire. Different negatively interface charge density values were applied on the transducer channels’ surface of the biosensors to represent as detected target biomolecules that will bind onto the surface of the transducer regions. Based on the results, more negatively interface charges density values presented on the sensing channels had reduced the electron carrier accumulation at the channel’s interface, therefore, reduced drain current flow between the source and drain terminal. With the increase number of the transducer channels, significant change in drain current for every applied negatively interface charges became more apparent and increased the sensitivity of the biosensor. The triple transducer channels silicon nanowire field-effect transistor biosensor had demonstrated highest sensitivity, that is 2.83 µA/e∙cm2, which indicates it has better response for the detection of interface charges, thus increases chances for transducer channels reaction to the target biomolecules during testing or diagnosis.

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Impedimetric Lectin Biosensor for Prostate Cancer Detection

2021-01-01 , Abd Rahman S.F. , Mohd Khairuddin Md Arshad , Subash Chandra Bose Gopinath , Mohamad Faris Mohamad Fathil , Sarry F. , Md Nor M.N.

There is considerable attention on the determination of prostate-specific antigen (PSA) glycosylation patterns for the early detection of prostate cancer, as it is one of the most reliable tumor biomarkers. In this study, the highly effective lectin-based biosensor utilizing gold interdigitated microelectrode was developed as a sensing transducer, coupled with electrochemical impedance spectroscopy (EIS) for the sensitive detection of biomolecules event on the device. The self-assembled monolayer using 11-mercaptoundecanoic acid was utilized to modify the sensor surface for the conjugation of Maackia amurensis lectin as biorecognition elements. The analytical analysis of the developed lectin biosensor with PSA glycosylation through impedimetric measurement exhibited a linear detection ranging from 100 pg/mL to 100 ng/mL and attained a detection limit of 27.6 pg/mL.

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Fabrication of Graphene Electrode via Graphene Transfer Method for Bisphenol A (BPA) Detection

2021-01-01 , Shukri N.I.B.A. , Norhayati Sabani , Ruslinda A. Rahim , Mohamad Faris Mohamad Fathil , Syarifah Norfaezah Sabki , Nur Hamidah Abdul Halim , Nur Syakimah Ismail

Exposure of BPA is a concern as BPA can seep into food or beverages from containers and can possibly effects on human health especially endocrine systems. An electrochemical-based aptasensor utilizing graphene was developed in detecting endocrine disrupting compound Bisphenol A (BPA, 4,4'-(propane-2,2-diyl) diphenol). The graphene modified electrode was developed via graphene transfer. Fabrication and characterization of graphene transfer was studied in this paper using Scanning Electron Microscopy (SEM) and High-Power Microscope (HPM). In this research, the investigation of interfacial characteristic modified graphene with aptasensor and recognition of BPA with aptasensor had been done using electrochemical impedance spectroscopy (EIS). The increment of charge transfer resistance (Rct) before and after recognition of BPA denoting the accumulation of charge at the electrode surface in this research.

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Impact of buried oxide thickness in substrate-gate integrated silicon nanowire field-effect transistor biosensor performance for charge sensing

2021-07-21 , Tan Y.M. , Mohamad Faris Mohamad Fathil , Mohammad Nuzaihan Md Nor , Norhayati Sabani , Teoh X.Y. , Mohd Khairuddin Md Arshad , Subash Chandra Bose Gopinath , Rahman S.F.A. , Uda Hashim

The paper investigated on performance in charge sensing for substrate-gate integrated silicon nanowire field-effect transistor biosensor at different thickness of the buried oxide layer, sandwiched in between the top-silicon and substrate layers. The device structures with different buried oxide thickness ranging from 100 to 200 nm were designed and simulated using the Silvaco ATLAS device simulation software. The increase of buried oxide thickness reduced the strength of induced electric field that contributes to the formation of inversion layer for current flow through the silicon nanowire channel, hence contributed to the increase in threshold voltage. For simulation of charge sensing, the device demonstrated the ability to identify different interface charge values ranging from -5×1010 to -9×1010 e· cm-2 applied on the surface of the silicon nanowire channel to represent target charge biomolecules that bound to the biosensor in actual detection. Significant change in threshold voltage can be observed due to the applied interface charge density values and was evaluated to determine the sensitivity for charge sensing performance. The device shows better performance when designed with buried oxide thickness of 200 nm at sensitivity of 1.151 V/e· cm-2.

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Cost-Effective Fabrication of Polydimethylsiloxane (PDMS) Microfluidics for Point-of-Care Application

2024-06-01 , Adilah Ayoib , Karim N.A.A.A. , Uda Hashim , Shahidah Arina Shamsuddin , Abd Rahman S.F. , Mohamad Faris Mohamad Fathil , Nor Azizah Parmin

Microfluidics fabrication pertains to the construction of small-scale devices and systems that manipulate and control small volumes of fluids. This process involves precise engineering and manufacturing procedures aimed at designing and producing these devices, which find applications in healthcare, environmental monitoring, and chemical analysis. The present study showcases an inexpensive approach to fabricate microfluidics channels using PDMS biopolymer and soft lithography technique to achieve laminar fluid flow. Initially, a robust and adhesive mold was created by fabricating a master template using several layers of SU-8 5 and SU-8 2015 negative photoresists. Subsequently, PDMS microfluidics channels were replicated and sealed onto a glass substrate through plasma bonding treatment. High-power microscopy images and profilometer analyses demonstrated successful fabrication with minimal deviation from the initial designs and the fabricated devices (less than 0.07 mm, less than 0.6°). Both the SU-8 master template and PDMS replicate displayed average microchannel height values and surface roughness of 100 μm and 0.26 µm or lower, respectively. Additionally, the fluid test confirmed laminar flow without any leakage post plasma oxidation, indicating the completion of an efficient and cost-effective fabrication process.

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Polysilicon nanowire with liquid gate control for pH sensing

2018-12 , Mohammad Nuzaihan Md Nor , M. F. Farizal , C. W. Chung , M. N. Aziz , Mohamad Faris Mohamad Fathil , C. Ibau , S. Johari , Mohd Khairuddin Md Arshad

Polysilicon nanowire based sensors have garnered great potential in serving as highly sensitive, label-free and real-time sensing for broad range of applications, that include but not limited to pH values, DNA molecules, proteins and single viruses. In this research, two distinct types of polysilicon nanowires are fabricated, one has an array of nanowires with a 100 nm width and the other is a single nanowire with 100 nm width. Top-down fabrication method is utilized to fabricate the polysilicon nanowire from silicon wafer using the conventional photolithography and reactive ion etching processes. The fabricated polysilicon nanowire have an approximately 100 nm in width, is then undergo surface modification, which is the nanowire is immersed into a 2% 3-aminopropyltriethoxysilane (APTES) to create a molecular binding chemistry, which results in amino (NH2) and silanol (SiOH) groups at the nanowire surface. Since the surface of the polysilicon is hole-dominated (p-type material), it responds well to changes in pH values. In this research, pH sensing is performed based on several types of standard aqueous pH buffer solutions (pH 2, pH 4, pH 7, pH 10 and pH 12) to demonstrate the electrical response of the sensor. At low pH, NH2 group is protonated, resulting in high proton ion acts as a positive gate. At high pH, SiOH group is deprotonated, resulting in bringing negative charges at the polysilicon nanowire surface and acts as a negative gate voltage. The sensitivity of the polysilicon nanowire attained was 207.1 fS/pH for array nanowire and 8.91 fS/pH for single nanowire, which shows excellent properties for pH sensing.

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