Now showing 1 - 10 of 20
  • Publication
    Remazol orange dye sensitized solar cell
    Water based Remazol Orange was utilized as the dye sensitizer for dye sensitized solar cell. The annealing temperature of TiO2 working electrode was set at 450 °C. The performance of the device was investigated between dye concentrations of 0.25 mM and 2.5 mM at three different immersion times (3, 12 and 24 hours). The adsorption peak of the dye sensitizer was evaluated using UV-Vis-Nir and the device performance was tested using solar cell simulator. The results show that the performance was increased at higher dye concentration and longer immersion time. The best device performance was obtained at 0.2% for dye concentration of 2.5 mM immersed at 24 hours.
  • Publication
    Low-cost integrated circuit packaging defect classification system using edge impulse and ESP32CAM
    (Institute of Advanced Engineering and Science (IAES), 2025-02)
    Muhammad Adni Kamaruddin
    ;
    Mohd Syafiq Mispan
    ;
    Aiman Zakwan Jidin
    ;
    Haslinah Mohd Nasir
    ;
    Defects in integrated circuit (IC) packaging are inevitable. Several factors can cause defects in IC packaging such as material quality, errors in machine and human handling operations, and non-optimized processes. An automated optical inspection (AOI) is a typical method to find defects in the IC manufacturing field. Nevertheless, AOI requires human assistance in the event of uncertain defect classification. Human inspection often misses very tiny defects and is inconsistent throughout the inspection. Therefore, this study proposed a low-cost IC packaging defect classification system using edge impulse and ESP32-CAM. The method involves training a deep learning model (i.e., convolutional neural network (CNN)) using a dataset of non-defective and defective ICs on Edge Impulse. For defective ICs, the top surface of the ICs is deliberately scratched to imitate the cosmetic defects. ICs with scratch-free on their top surfaces are considered non-defective ICs. A successfully trained model using Edge Impulse is subsequently deployed on ESP32-CAM. The model is optimized to fit the limited resources of the ESP32-CAM. By using the built-in camera in ESP32-CAM, the trained model can perform a real-time image classification of non-defective/defective ICs. The proposed system achieves 86.1% prediction accuracy by using a 1,571 image dataset of defective and non-defective ICs.
  • Publication
    Comprehensive study on gate recess step for the fabrication of high-speed InGaAs/InAlAs/InP pHEMT
    We report a comprehensive etching study on the gate recess step for the fabrication of the novel high speed pHEMT devices. The experiments focused on the elimination of 'hump' structure as a result of an incomplete etching process at the InGaAs cap layer. In this work, two types of test samples were used, namely bulk InGaAs and epitaxial structure together with an etch stop layer. The result showed that the etch rate of bulk InGaAs is about 360 A/min and the percentage of dome height is consistent at approximately 25%. Meanwhile, the study on pHEMT epitaxial layer showed that the etching time of 3 minutes is sufficient in order to completely remove the cap layer. Gate leakage current of magnitude more than 10 times lower is observed on the devices that engaging Succinic Acid as the gate recess etching agent. The optimized processing steps will tailor for highly reproducible pHEMT fabrication process for high speed applications.
      37  9
  • Publication
    The Design and Analysis of High Q Factor Film Bulk Acoustic Wave Resonator for Filter in Super High Frequency
    Filtering process is one of the highlighted issues when the operating frequency is up to medium or high GHz range in wireless transceiver system. The development of high performance, small size, filter on chip operating in GHz frequency range is the requirement of present and future wireless transceiver systems. The conventional frequency bands, below 6 GHz are already congested, thus, to satisfy this demand, the research into transceiver systems working at frequencies higher than 6 GHz has been growing. Therefore, this work proposed the design and optimization of film bulk acoustic wave resonator (FBAR) operating in frequency 7 GHz to 10 GHz with high quality (Q) factor. The effect of using different geometrical parameters to achieve high Q factor FBAR in these frequency bands is analysed. The designed FBAR achieved Q factor of 1767 at 7 GHz and 1237 at 10 GHz by using aluminium nitride as the piezoelectric thin film and molybdenum as the electrode.
      2
  • Publication
    Impedance and modulus spectroscopy of polycrystalline Ba0.9995La0.0005TiO3for multilayer ceramic capacitor
    ( 2021-07-21)
    Tiong Yuan Tze
    ;
    ; ;
    Ku Noor Dhaniah Ku Muhsen
    ;
    ;
    Wahab Y.A.
    ;
    Sagadevan S.
    ;
    Sebastian T.
    ;
    Arturo R.L.D.
    Ba0.9995La0.0005TiO3 ceramics prepared via solid-state reaction route was found to be phase pure at the final sintering temperature of 1300°C for 16 hours. The dielectric constant was varied from 1900 to 2800 from 10 Hz to 100 kHz. Impedance spectroscopy is a powerful technique to study the complexities of ceramic materials such as homogeneity and inhomogeneity of materials that being process during production of most electronic materials. An electronic ceramic component can be visualized as a grain, grain boundary and electrode system. Impedance spectroscopy is being widely used to separate out contribution of the bulk and the grain boundary to the overall equivalent circuit models. Fixed frequency plots of dielectric constant versus temperature for Ba0.9995La0.0005TiO3 ceramics shows typical perovskite response with Curie temperature, Tc about 115 °C and fit with the equivalent circuit which contributed by bulk and grain boundary response.
      1  35
  • Publication
    Analysis on Square and Circular Inductor for a High Q-Factor Inductor
    This paper presents the high-quality (Q) factor inductors using Silicon-on-sapphire (SOS) for the 10GHz to 20GHz frequency band. Inductors are designed on SOS because of their advantages, including high resistivity and low parasitic capacitance. This paper compares square and circular inductor topologies for high-quality (Q) factor inductors using HFSS software for the high-frequency band. Both inductors have been designed with the same width and thickness to make them comparable with each other. The comparison shows that a circular inductor achieves the highest Q-factor. Furthermore, the circular and square inductor's Q-factor, inductance, and resistance are analyzed. As a result, the circular inductor has the maximum Q-factor of 89.34 at 10.6GHz for 0.29nH, while the square inductor has obtained a maximum Q-factor of 80.72 at 10GHz for 0.40nH inductance.
      2  29
  • Publication
    Characteristics of film bulk acoustic wave resonator using different electrode materials
    ( 2021-07-21) ;
    Jing Y.W.
    ;
    Film bulk acoustic wave resonator (FBAR) is a device that consists of a thin-film piezoelectric, which is sandwiched between the top and bottom electrodes. FBAR has been widely used in radio frequency (RF) front-end circuits such as RF filters due to its advantages of high quality (Q) factor. The performance of FBAR is highly related to the piezoelectric material. The piezoelectric material such as aluminum nitride (AlN) and zinc oxide (ZnO) are commonly used in FBAR. Other than piezoelectric material, another important element in designing an FBAR is the electrode materials. Different electrode materials affect the performance of FBAR in terms of Q factor and electromechanical coupling coefficient (k2eff) due to their material properties. Therefore, in this work, FBARs operating at frequencies of 5 GHz to 10 GHz by using AlN as the piezoelectric material with different electrode materials, which are molybdenum (Mo) and aluminum (Al) were designed. The performance of the designed FBARs were compared in terms of Q factor and k2eff. Based on the results, the Q factor of FBAR with Mo as electrodes achieved the highest value of 16300 at 5 GHz, while the Q factor of FBAR with Al as electrodes achieved the highest value of 13726 at 5 GHz. The k2eff of FBAR with Al as electrodes achieved the highest value of 6.71% at 7 GHz, while FBAR with Mo as electrodes achieved the highest coupling coefficient of 5.78% at 6 GHz.
      1  23
  • Publication
    A 12 GHz LC-VCO Implemented with S’ shape Inductor using silicon-on sapphire substrate
    A voltage-controlled oscillator (VCO) is an electronic oscillator whose oscillation frequency is controlled by a voltage input. In a VCO, low-phase noise while consuming less power is preferred. The tuning gain and noise in the control signal produce phase noise; more noise or tuning gain implies more phase noise. Sources of flicker noise (1/f noise) in the circuit, the output power level, and the loaded Q factor of the resonator are all crucial factors that influence phase noise. As a result, creating a resonator with a high Q-factor is essential for improving VCO performance. As a result, this paper describes a 12 GHz LC Voltage- Controlled Oscillator (VCO) employed with a ‘S’ shape inductor to improve phase noise and power performance. The phase noise for the VCO was reduced using a noise filtering technique. To reduce substrate loss and improve the Q factor, the inductor was designed on a high-resistivity Silicon-on Sapphire (SOS) substrate. At 12 GHz, the optimised S’ shape inductor has the highest Q-factor of 50.217. At 10 MHz and 100 MHz, the phase noise of the 12 GHz LC-VCO was -131.33 dBc/Hz and -156.71 dBc/Hz, respectively. With a 3.3 V power supply, the VCO core consumes 26.96 mW of power. Based on the findings, it is concluded that using an ‘S’ shape inductor in the VCO circuit will enable the development of low-cost, high-performance, very low-power system-on-chip wireless transceivers with longer battery life.
      3  46
  • Publication
    Carbon nanotube as electrode in film bulk acoustic wave resonator for improved performance
    Electrode material is one of the important material in designing FBAR. Different electrode materials will have different characteristic and properties. The different in properties will also produce different performance such as the quality factor or electromechanical coupling coefficient (k2eff). Study has shown that carbon nanotube (CNT) has been used as electrode in the fabrication of FBAR. The result shows that CNT offers higher Q factor compare to metal electrode. Therefore, in this work it is focused to design the zinc oxide (ZnO) based on FBAR with carbon nanotube (CNT) and aluminium (Al) as electrode with frequencies range of 6 GHz to 8 GHz. Analysis shows that CNT has higher Q factor compared to Al where the highest Q factor of CNT recorded is 1543 while Al is 1268 at frequency of 8 GHz with thickness of 30 nm at resonance area of 50 μm × 50 μm. For FBAR operation at 6 GHz, CNT shows the highest Q factor of 1164 while Al is 876 at thickness of 30 nm at resonance area of 50 μm × 50 μm. CNT and Al at 7 GHz also show the highest Q factor at thickness of 30 nm with resonance area of 50 μm × 50 μm by 1341 and 993 respectively. On the other hand, in term of k2eff, Al has higher value of k2eff compare to CNT where for 6 GHz the highest value of Al recorded is 0.062 while CNT is 0.026 at thickness of 30 nm with resonance area of 50 μm × 50 μm. For 7 GHz the highest k2eff of Al achieved is 0.067 while CNT is 0.042 at thickness of 30 nm. For 8 GHz, the highest k2eff of Al achieved is 0.073 while CNT is 0.025 at thickness of 30 nm.
      6  18
  • Publication
    Design and analysis of wideband ladder-type film bulk acoustic wave resonator filters in Ku-Band
    ( 2013-06) ;
    Kriang Shah
    ;
    Jugdutt Singh
    ;
    This paper presents the design of ladder-type filters based on film bulk acoustic wave resonator (FBAR) in Ku-band. The proposed FBAR filter has an insertion loss of −3 dB, out-of-band rejection of −12 dB and 3 dB bandwidth of 1.0 GHz from 15 GHz to 16 GHz. Based on the characteristics of the FBAR filter, the expected characteristics of FBAR resonators are determined by using the 1D numerical analysis. This design proves that it is possible to design a wide-bandwidth FBAR filter in Ku-band.
      5  27