Uda Hashim - Academia.edu (original) (raw)

Papers by Uda Hashim

Journal of Electronic Materials

This paper discusses the influence of bonding wires and epoxy mold compounds (EMC) on intermetall... more This paper discusses the influence of bonding wires and epoxy mold compounds (EMC) on intermetallic compound (IMC) diffusion kinetics and apparent activation energies (E aa ) of CuAl and AuAl IMCs in a fineline ball grid array package. The objective of this study is to study the CuAl and AuAl IMC growth rates with different epoxy mold compounds and to determine the apparent activation energies of different combination of package bills of materials. IMC thickness measurement has been carried out to estimate the coefficient of diffusion (D o ) and E aa various aging conditions of different EMCs and bonding wires. Apparent activation energies (E aa ) of both wire types were investigated after high temperature storage life tests (HTSL) for both molding compounds. Au bonds were identified to have faster IMC formation, compared to slower IMC growth of Cu. The E aa obtained for CuAl IMC diffusion kinetics are 1.08 and 1.04 eV with EMC A and EMC B, respectively. For AuAl IMC diffusion kinetics, the E aa obtained are 1.04 and 0.98 eV, respectively, on EMC A and EMC B. These values are close to previous HTSL studies conducted on Au and Cu ball bonds and are in agreement to the theory of HTSL performance of Au and Cu bonding wires.Overall, EMC B shows slightly lower apparent activation energy (E aa ) valueas in CuAl and AuAl IMCs. This proves that the different types of epoxy mold compounds have some influence on IMC growth rates.

Book review article in Microelectronics Reliability journal.

ABSTRACT TiO2 nanoparticles were synthesized on SiO2 substrate via sol–gel spin coating method. T... more ABSTRACT TiO2 nanoparticles were synthesized on SiO2 substrate via sol–gel spin coating method. TiO2 film was characterized using field emission electron microscope (FESEM), X-ray diffractometer (XRD), and Ultra violet visible (Uv-Vis) spectroscopy. Metal-semiconductor-metal (MSM) photodetectors with aluminum (Al) as contact electrode has been successfully fabricated for ultraviolet (UV) detection. It was found that the photocurrent increase 6.28 orders of magnitude higher than the dark current at 5 V applied bias voltage. It was observed that the maximum responsivity of the Al/TiO2/Al MSM photodetector was 39.25 μAW–1, at 350 nm. The response and recovery time of the fabricated device were 2.5 and 2.8 s, respectively.

RSM 2013 IEEE Regional Symposium on Micro and Nanoelectronics, 2013

ABSTRACT

Applied Mechanics and Materials, 2015

Optimization gap size and integration of TiO2 nanoparticles thin film produce a sensitive sensor ... more Optimization gap size and integration of TiO2 nanoparticles thin film produce a sensitive sensor device. Sol-gel spin coated TiO2 nanoparticles thin film is coated on a conventional fabricated IDEs with gap sizes of 7 µm, 10 µm, 14 µm and 17 µm which is then validated through electrical characterization. I-V characteristics of without and with TiO2 thin film of various gap sizes are subjected to pH test are then plotted to describe the resistance of the devices and correlate with the sensitivity measurement. Sensing devices show that devices with larger spacing and greater pH values have higher current. On the other hand, integration of TiO2 thin film reduced the resistance of devices. Among the four gap sizes, 7 µm gap sized device is the most sensitive one due to the tremendous difference after small amount of pH dropped on surface, thus lowering the detection limit.

Advanced Materials Research, 2013

ABSTRACT

The biological and medical fields have taken the full advantage of nanotechnology in the developm... more The biological and medical fields have taken the full advantage of nanotechnology in the development of transducers and biochips which are capable of characterizing bio-molecules. The research about the characterisation of nanoelectrode transducer using biomolecule detection technique has been studied to understand the important relationship between the transducer and the nanostructure which leads to high sensitivity and selectivity. We have applied conventional photolithography technique by using polysilicon on silicon substrate to fabricate a nanoelectrode transducer and employed as an electrochemical microelectrode sensors to measure the bio-molecules electrical characteristics. RIE and LPCVD processes were used during the transducer fabrication. Characterization is made both physically and electrically to check the surface topography and the electrical characteristics such as capacitance and conductance. Purchased pH buffer solutions which varied from pH1 to pH12 is dropped on the nanoelectrode and the effect on it is investigated for the application in pH measurement. This research has proven that increase in pH concentration is proportional with capacitance.

A highly sensitive and non-invasive label-free biosensor were demonstrated for glucose detection ... more A highly sensitive and non-invasive label-free biosensor were demonstrated for glucose detection using (3-Aminopropyl)triethoxysilane (APTES) and glucose oxidase (GOx) surface modified polysilicon nanogap (PSNG) lab-on-chip. Fabricated gap size below 100 nm nanogap (NG) was used to discriminate the detection of the prepared dextrose monohydrate (DEX) which used as reference. The results were compared with salivary glucose (SAL) samples and an on spot blood glucometer. A simple immobilization step of APTES and GOx was demonstrated and the result shows an excellent catalytic activity toward the oxidation of glucose with a current sensitivity of 42.08 μA mM−1 cm−2(or NG conductance sensitivity of 165.3 nS cm−1). It was found that the working capability of this enzyme based biosensor was extremely wide linear ranging from 5 μM to 50 mM, and the limit of detection (LOD) can be achieved down to 0.6 μM. Moreover, the amperometric response has affectively distinguished, the sensor response time of 3s is achieved. The reproducibility and stability of the enzymatic activity of biosensor were successfully distinguished for glucose sensing. AC dielectric and impedance spectroscopy measurement also shows insignificant effect of polarization which is due to the accumulation of ions (double layers) on the surface of PSNG electrodes. Therefore, this glucose biosensor could be an attractive candidate for commercialization as a point-of-care clinical diagnostic tool.

Sugar is carbohydrate sweet-flavoured substance that composed of carbon, oxygen and hydrogen. It ... more Sugar is carbohydrate sweet-flavoured substance that composed of carbon, oxygen and hydrogen. It is an important component to provide sweet taste in food. Besides, it also provides immediate energy to complete daily routine life. However, uncontrolled amount of sugar can lead to serious health complications and diseases such as Hypoglycemia (low sugar in blood), syndrome X, diabetes and heart disease. Low amount of sugar in bloodstream may cause nausea and dizziness. Besides that, it also can be used as sensor to detect the amount of sugar in beverages. Here, sugar is used as a reference measurement to test the functionality of the device before testing it in real life using glucose samples. In future, real urine samples will be used to measure concentration of glucose in diabetic patients. In this paper, sugar concentration measurement based on microgap biosensor is fabricated by using conventional photolithography process. Silicon was used as the substrate material and followed by layers of Silicon dioxide (SiO2), Polysilicon, Titanium (Ti) and Gold (Au). Chrome mask were used to transfer pattern of microgap and contact pads onto the silicon substrate. The device design has been optimised to achieve few performance factors that includes accuracy, sensitivity, response time and fabrication cost. A number of sugar concentrations were prepared by diluting it with DI water for measurement process by electrical characterization. In this work, studies and analysis were conducted based on different concentration of sugar on constant sized microgap and based on different size of microgap structure on constant sugar concentration. As the result, the experiment has been successfully yielded a high sensitive microgap sensor and the lowest detected sugar concentration sample is 0.0245gml -1 . This method of biosensing provides a very simple and promising detection tech-nique for any kind of biomolecules that includes proteins, DNA, enzymes, antibody and antigen.

For a submicron photolithography process, there is little room for error. In this paper, an optim... more For a submicron photolithography process, there is little room for error. In this paper, an optimized technique for photoresist (PR) development is reported, to fabricate a nanogap biosensor for application in biomedical nano diagnostics. The pattern transfer on the wafer substrate requires precise alignment and Deep Ultra-Violet (DUV) light exposure. This research describes the photolithography process to develop a standard manufacturing procedure for pattern transfer from chrome mask. The key factor for PR development is understood and the optimization is done based on the PR thickness, spin speed, spin time, exposure time, post-exposure bake (PEB) time, developer concentration and developing time to achieve the design feature size of 1 micron. The PR is coated and spun at 3000 rpm and 5000 rpm at 30s and 40s respectively to form a very thin layer. However, the UV exposure time is remained constant at 10s. After the pattern transfer, the wafer is immersed in different concentrations of RD6 developer to develop the PR. To further improve the resolution of image transfer, the PEB time is also optimized for a better throughput on feature size. These optimizations are important to reduce the dimension error and were able to achieve error free design to protect critical dimension and prevent device failure.

One of the advantages of silicon substrate over other semiconductor substrate is the high tempera... more One of the advantages of silicon substrate over other semiconductor substrate is the high temperature process capability of the silicon. In this work, silicon wafer is used for thermal processing which involves many high temperature processes such as oxidation and deposition. Thin films on the wafer surface are investigated for its thickness and uniformity. Silicon dioxide (SiO 2 ) is initially grown using wet oxidation method and characterized for its thickness using FilmetricsSpectrometer. The thickness of SiO 2 achieved is less than 300nm. Silicon Nitride (Si 3 N 4 ) is then deposited by sputter method and its thickness is measured at 210 nm. For the electrode, polysilicon (PolySi) is deposited using Low Pressure Chemical Vapor Deposition (LPCVD) process. Silane (SiH 4 ) is used as the source forPolySi deposition and the thickness is measured at 160nm. Standard deviation is calculated based on the layer thickness and the uniformity is checked across 5 points on the wafer. Hence, it is very important to have a uniform layer across the wafer surface for a defect free device and at the same time it protects the sensitivity of the sensor.

For rapid screening nano size biomolecules, a device must be designed in nano sizes, compact and ... more For rapid screening nano size biomolecules, a device must be designed in nano sizes, compact and ultrahigh sensitive. The most interesting function of the devices is to transduce the binding of biomolecules and devices into electrical signals for further analysis. Over the past few years, nanostructures have emerged as an excellent material to be applied in electrical biosensor. It is because nanostructure-based biosensors have improved much better in rapid detection, sensitivity and selectivity for biosensing compared to conventional biosensing technologies. Here, we highlight the latest developments of carbon nanotubesbiosensors for medical application and their performance for the detection of biomolecules.

Deionized water is essential to many medical, manufacturing, food processing, and other industria... more Deionized water is essential to many medical, manufacturing, food processing, and other industrial applications. The research about the characterisation of nanoelectrode transducer using biomolecule detection technique has been studied to understand the important relationship between the biomolecule and the nanoelectrode. Conventional photolithography technique is applied by using polysilicon on silicon substrate to fabricate a nanoelectrode transducer and employed as an electrochemical nanoelectrode sensor to measure the DI water electrical characteristics. Physical characteristics checked optically using Single Electron Microscopy (SEM), low and high power microscopy to inspect the dimensions and the absence of particles. Then, by dropping the DI water on the nanoelectrode, electrical characteristics are measured using Dielectric Analyzer and probe station to measure the capacitance of the transducer. From the experiment, this ultra-high sensitive device is able to measure the capacitance as low as 98nF in a very low frequency. The effect on DI water is investigated and optimized for the application in DI water electrical measurement.

Photomasks are used as stencil to print images on semiconductor material. This study represents d... more Photomasks are used as stencil to print images on semiconductor material. This study represents design and specifications of photomask for microfluidic fabrication. For a precise pattern transfer, the photomask should meet with certain considerations such as critical dimension uniformity, resolution and alignment. This paper explains the design of microfluidics with three channels using AutoCAD software for lab-on-chip application. Total surface area of the device is 242.52mm 2 in which the width and length is 12.00mm and 20.21mm respectively. The device was designed in particular size to meet its behavior as a disposable chip and increases the economic value when it is fabricated.

Trans Tech Publications, Switzerland, 2013

This paper explains the most crucial part of any microchip fabrication, which is the mask design ... more This paper explains the most crucial part of any microchip fabrication, which is the mask design for photolithography process. The design is initially sketched roughly to meet the design specification and later on designed using AutoCAD software. Therefore, to meet the required criteria, the overall width and length of the device is optimized at 12mm and 20.21mm respectively. Optimization of the size is done based on the chip behavior as a disposable chip and adding an economical value when it is commercialized. The nano electrode mask layout comprises of four sets of design which are single gaps for size reduction, single gaps for size expansion, multiple gaps for size reduction and multiple gaps for size expansion. While, the second chrome mask is fabricated for gold contact padding with two types of design sets, one is for single gaps and another is for multiple gaps. Both mask designs were sent for chrome mask fabrication for future use in biosensor fabrication.
Introduction

2011 IEEE Regional Symposium on Micro and Nano Electronics, 2011

Acid oxidation is one of the purification method which has been used to open up the caps, removin... more Acid oxidation is one of the purification method which has been used to open up the caps, removing carbonaceous and metal particles impurities, and attaching functional group (carboxylic groups, -COOH) at the opened caps and MWCNT surfaces. Unfortunately, this method can cause the structural damages of MWCNT, cut them into shorter length and reduced their performance. However, it is reported that the structure damage of CNT can be acceptable if it is not exceeding 4% of damages. Several characterization techniques will be used to study the composition of functionalized MWCNT and measuring the percent damages of functionalized MWCNT.

Journal of Renewable and Sustainable Energy, 2014

ABSTRACT High-quality Cadmium sulfide (CdS) nanostructures for high-efficiency optoelectronic dev... more ABSTRACT High-quality Cadmium sulfide (CdS) nanostructures for high-efficiency optoelectronic devices were prepared at different annealing temperatures using a sol-gel spin-coating method. Atomic force microscopy and X-ray diffraction were performed to measure the structural properties of the nanostructures and calculate their bulk modulus using our model. Thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry, and Fourier transform infrared, UV-Vis, and photoluminescence spectroscopies were used to investigate the thermal and optical properties of the samples. The electrical characteristics of the CdS nanostructures were analyzed to determine their gain.

Journal of Electronic Materials

This paper discusses the influence of bonding wires and epoxy mold compounds (EMC) on intermetall... more This paper discusses the influence of bonding wires and epoxy mold compounds (EMC) on intermetallic compound (IMC) diffusion kinetics and apparent activation energies (E aa ) of CuAl and AuAl IMCs in a fineline ball grid array package. The objective of this study is to study the CuAl and AuAl IMC growth rates with different epoxy mold compounds and to determine the apparent activation energies of different combination of package bills of materials. IMC thickness measurement has been carried out to estimate the coefficient of diffusion (D o ) and E aa various aging conditions of different EMCs and bonding wires. Apparent activation energies (E aa ) of both wire types were investigated after high temperature storage life tests (HTSL) for both molding compounds. Au bonds were identified to have faster IMC formation, compared to slower IMC growth of Cu. The E aa obtained for CuAl IMC diffusion kinetics are 1.08 and 1.04 eV with EMC A and EMC B, respectively. For AuAl IMC diffusion kinetics, the E aa obtained are 1.04 and 0.98 eV, respectively, on EMC A and EMC B. These values are close to previous HTSL studies conducted on Au and Cu ball bonds and are in agreement to the theory of HTSL performance of Au and Cu bonding wires.Overall, EMC B shows slightly lower apparent activation energy (E aa ) valueas in CuAl and AuAl IMCs. This proves that the different types of epoxy mold compounds have some influence on IMC growth rates.

Book review article in Microelectronics Reliability journal.

ABSTRACT TiO2 nanoparticles were synthesized on SiO2 substrate via sol–gel spin coating method. T... more ABSTRACT TiO2 nanoparticles were synthesized on SiO2 substrate via sol–gel spin coating method. TiO2 film was characterized using field emission electron microscope (FESEM), X-ray diffractometer (XRD), and Ultra violet visible (Uv-Vis) spectroscopy. Metal-semiconductor-metal (MSM) photodetectors with aluminum (Al) as contact electrode has been successfully fabricated for ultraviolet (UV) detection. It was found that the photocurrent increase 6.28 orders of magnitude higher than the dark current at 5 V applied bias voltage. It was observed that the maximum responsivity of the Al/TiO2/Al MSM photodetector was 39.25 μAW–1, at 350 nm. The response and recovery time of the fabricated device were 2.5 and 2.8 s, respectively.

RSM 2013 IEEE Regional Symposium on Micro and Nanoelectronics, 2013

ABSTRACT

Applied Mechanics and Materials, 2015

Optimization gap size and integration of TiO2 nanoparticles thin film produce a sensitive sensor ... more Optimization gap size and integration of TiO2 nanoparticles thin film produce a sensitive sensor device. Sol-gel spin coated TiO2 nanoparticles thin film is coated on a conventional fabricated IDEs with gap sizes of 7 µm, 10 µm, 14 µm and 17 µm which is then validated through electrical characterization. I-V characteristics of without and with TiO2 thin film of various gap sizes are subjected to pH test are then plotted to describe the resistance of the devices and correlate with the sensitivity measurement. Sensing devices show that devices with larger spacing and greater pH values have higher current. On the other hand, integration of TiO2 thin film reduced the resistance of devices. Among the four gap sizes, 7 µm gap sized device is the most sensitive one due to the tremendous difference after small amount of pH dropped on surface, thus lowering the detection limit.

Advanced Materials Research, 2013

ABSTRACT

The biological and medical fields have taken the full advantage of nanotechnology in the developm... more The biological and medical fields have taken the full advantage of nanotechnology in the development of transducers and biochips which are capable of characterizing bio-molecules. The research about the characterisation of nanoelectrode transducer using biomolecule detection technique has been studied to understand the important relationship between the transducer and the nanostructure which leads to high sensitivity and selectivity. We have applied conventional photolithography technique by using polysilicon on silicon substrate to fabricate a nanoelectrode transducer and employed as an electrochemical microelectrode sensors to measure the bio-molecules electrical characteristics. RIE and LPCVD processes were used during the transducer fabrication. Characterization is made both physically and electrically to check the surface topography and the electrical characteristics such as capacitance and conductance. Purchased pH buffer solutions which varied from pH1 to pH12 is dropped on the nanoelectrode and the effect on it is investigated for the application in pH measurement. This research has proven that increase in pH concentration is proportional with capacitance.

A highly sensitive and non-invasive label-free biosensor were demonstrated for glucose detection ... more A highly sensitive and non-invasive label-free biosensor were demonstrated for glucose detection using (3-Aminopropyl)triethoxysilane (APTES) and glucose oxidase (GOx) surface modified polysilicon nanogap (PSNG) lab-on-chip. Fabricated gap size below 100 nm nanogap (NG) was used to discriminate the detection of the prepared dextrose monohydrate (DEX) which used as reference. The results were compared with salivary glucose (SAL) samples and an on spot blood glucometer. A simple immobilization step of APTES and GOx was demonstrated and the result shows an excellent catalytic activity toward the oxidation of glucose with a current sensitivity of 42.08 μA mM−1 cm−2(or NG conductance sensitivity of 165.3 nS cm−1). It was found that the working capability of this enzyme based biosensor was extremely wide linear ranging from 5 μM to 50 mM, and the limit of detection (LOD) can be achieved down to 0.6 μM. Moreover, the amperometric response has affectively distinguished, the sensor response time of 3s is achieved. The reproducibility and stability of the enzymatic activity of biosensor were successfully distinguished for glucose sensing. AC dielectric and impedance spectroscopy measurement also shows insignificant effect of polarization which is due to the accumulation of ions (double layers) on the surface of PSNG electrodes. Therefore, this glucose biosensor could be an attractive candidate for commercialization as a point-of-care clinical diagnostic tool.

Sugar is carbohydrate sweet-flavoured substance that composed of carbon, oxygen and hydrogen. It ... more Sugar is carbohydrate sweet-flavoured substance that composed of carbon, oxygen and hydrogen. It is an important component to provide sweet taste in food. Besides, it also provides immediate energy to complete daily routine life. However, uncontrolled amount of sugar can lead to serious health complications and diseases such as Hypoglycemia (low sugar in blood), syndrome X, diabetes and heart disease. Low amount of sugar in bloodstream may cause nausea and dizziness. Besides that, it also can be used as sensor to detect the amount of sugar in beverages. Here, sugar is used as a reference measurement to test the functionality of the device before testing it in real life using glucose samples. In future, real urine samples will be used to measure concentration of glucose in diabetic patients. In this paper, sugar concentration measurement based on microgap biosensor is fabricated by using conventional photolithography process. Silicon was used as the substrate material and followed by layers of Silicon dioxide (SiO2), Polysilicon, Titanium (Ti) and Gold (Au). Chrome mask were used to transfer pattern of microgap and contact pads onto the silicon substrate. The device design has been optimised to achieve few performance factors that includes accuracy, sensitivity, response time and fabrication cost. A number of sugar concentrations were prepared by diluting it with DI water for measurement process by electrical characterization. In this work, studies and analysis were conducted based on different concentration of sugar on constant sized microgap and based on different size of microgap structure on constant sugar concentration. As the result, the experiment has been successfully yielded a high sensitive microgap sensor and the lowest detected sugar concentration sample is 0.0245gml -1 . This method of biosensing provides a very simple and promising detection tech-nique for any kind of biomolecules that includes proteins, DNA, enzymes, antibody and antigen.

For a submicron photolithography process, there is little room for error. In this paper, an optim... more For a submicron photolithography process, there is little room for error. In this paper, an optimized technique for photoresist (PR) development is reported, to fabricate a nanogap biosensor for application in biomedical nano diagnostics. The pattern transfer on the wafer substrate requires precise alignment and Deep Ultra-Violet (DUV) light exposure. This research describes the photolithography process to develop a standard manufacturing procedure for pattern transfer from chrome mask. The key factor for PR development is understood and the optimization is done based on the PR thickness, spin speed, spin time, exposure time, post-exposure bake (PEB) time, developer concentration and developing time to achieve the design feature size of 1 micron. The PR is coated and spun at 3000 rpm and 5000 rpm at 30s and 40s respectively to form a very thin layer. However, the UV exposure time is remained constant at 10s. After the pattern transfer, the wafer is immersed in different concentrations of RD6 developer to develop the PR. To further improve the resolution of image transfer, the PEB time is also optimized for a better throughput on feature size. These optimizations are important to reduce the dimension error and were able to achieve error free design to protect critical dimension and prevent device failure.

One of the advantages of silicon substrate over other semiconductor substrate is the high tempera... more One of the advantages of silicon substrate over other semiconductor substrate is the high temperature process capability of the silicon. In this work, silicon wafer is used for thermal processing which involves many high temperature processes such as oxidation and deposition. Thin films on the wafer surface are investigated for its thickness and uniformity. Silicon dioxide (SiO 2 ) is initially grown using wet oxidation method and characterized for its thickness using FilmetricsSpectrometer. The thickness of SiO 2 achieved is less than 300nm. Silicon Nitride (Si 3 N 4 ) is then deposited by sputter method and its thickness is measured at 210 nm. For the electrode, polysilicon (PolySi) is deposited using Low Pressure Chemical Vapor Deposition (LPCVD) process. Silane (SiH 4 ) is used as the source forPolySi deposition and the thickness is measured at 160nm. Standard deviation is calculated based on the layer thickness and the uniformity is checked across 5 points on the wafer. Hence, it is very important to have a uniform layer across the wafer surface for a defect free device and at the same time it protects the sensitivity of the sensor.

For rapid screening nano size biomolecules, a device must be designed in nano sizes, compact and ... more For rapid screening nano size biomolecules, a device must be designed in nano sizes, compact and ultrahigh sensitive. The most interesting function of the devices is to transduce the binding of biomolecules and devices into electrical signals for further analysis. Over the past few years, nanostructures have emerged as an excellent material to be applied in electrical biosensor. It is because nanostructure-based biosensors have improved much better in rapid detection, sensitivity and selectivity for biosensing compared to conventional biosensing technologies. Here, we highlight the latest developments of carbon nanotubesbiosensors for medical application and their performance for the detection of biomolecules.

Deionized water is essential to many medical, manufacturing, food processing, and other industria... more Deionized water is essential to many medical, manufacturing, food processing, and other industrial applications. The research about the characterisation of nanoelectrode transducer using biomolecule detection technique has been studied to understand the important relationship between the biomolecule and the nanoelectrode. Conventional photolithography technique is applied by using polysilicon on silicon substrate to fabricate a nanoelectrode transducer and employed as an electrochemical nanoelectrode sensor to measure the DI water electrical characteristics. Physical characteristics checked optically using Single Electron Microscopy (SEM), low and high power microscopy to inspect the dimensions and the absence of particles. Then, by dropping the DI water on the nanoelectrode, electrical characteristics are measured using Dielectric Analyzer and probe station to measure the capacitance of the transducer. From the experiment, this ultra-high sensitive device is able to measure the capacitance as low as 98nF in a very low frequency. The effect on DI water is investigated and optimized for the application in DI water electrical measurement.

Photomasks are used as stencil to print images on semiconductor material. This study represents d... more Photomasks are used as stencil to print images on semiconductor material. This study represents design and specifications of photomask for microfluidic fabrication. For a precise pattern transfer, the photomask should meet with certain considerations such as critical dimension uniformity, resolution and alignment. This paper explains the design of microfluidics with three channels using AutoCAD software for lab-on-chip application. Total surface area of the device is 242.52mm 2 in which the width and length is 12.00mm and 20.21mm respectively. The device was designed in particular size to meet its behavior as a disposable chip and increases the economic value when it is fabricated.

Trans Tech Publications, Switzerland, 2013

This paper explains the most crucial part of any microchip fabrication, which is the mask design ... more This paper explains the most crucial part of any microchip fabrication, which is the mask design for photolithography process. The design is initially sketched roughly to meet the design specification and later on designed using AutoCAD software. Therefore, to meet the required criteria, the overall width and length of the device is optimized at 12mm and 20.21mm respectively. Optimization of the size is done based on the chip behavior as a disposable chip and adding an economical value when it is commercialized. The nano electrode mask layout comprises of four sets of design which are single gaps for size reduction, single gaps for size expansion, multiple gaps for size reduction and multiple gaps for size expansion. While, the second chrome mask is fabricated for gold contact padding with two types of design sets, one is for single gaps and another is for multiple gaps. Both mask designs were sent for chrome mask fabrication for future use in biosensor fabrication.
Introduction

2011 IEEE Regional Symposium on Micro and Nano Electronics, 2011

Acid oxidation is one of the purification method which has been used to open up the caps, removin... more Acid oxidation is one of the purification method which has been used to open up the caps, removing carbonaceous and metal particles impurities, and attaching functional group (carboxylic groups, -COOH) at the opened caps and MWCNT surfaces. Unfortunately, this method can cause the structural damages of MWCNT, cut them into shorter length and reduced their performance. However, it is reported that the structure damage of CNT can be acceptable if it is not exceeding 4% of damages. Several characterization techniques will be used to study the composition of functionalized MWCNT and measuring the percent damages of functionalized MWCNT.

Journal of Renewable and Sustainable Energy, 2014

ABSTRACT High-quality Cadmium sulfide (CdS) nanostructures for high-efficiency optoelectronic dev... more ABSTRACT High-quality Cadmium sulfide (CdS) nanostructures for high-efficiency optoelectronic devices were prepared at different annealing temperatures using a sol-gel spin-coating method. Atomic force microscopy and X-ray diffraction were performed to measure the structural properties of the nanostructures and calculate their bulk modulus using our model. Thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry, and Fourier transform infrared, UV-Vis, and photoluminescence spectroscopies were used to investigate the thermal and optical properties of the samples. The electrical characteristics of the CdS nanostructures were analyzed to determine their gain.