Asrulnizam Abd Manaf

Post-process die-level electromagnetic field analysis on microwave CMOS low-noise amplifier for first-pass silicon fabrication success

In this study, the die-level electromagnetic interaction between components and parasitic interconnection extraction are evaluated with the measurement results of a 0.13µm radio-frequency CMOS low-noise amplifier (LNA). This work aims to achieve first-pass silicon fabrication success to avoid costly and time-consuming additional fabrications for optimization. To achieve this target, a full-wave 3D-planar electromagnetic (EM) solver called Sonnet is applied, and simplification techniques are introduced for complex circuits. The layout of a fabricated LNA chip was modeled and analyzed in an EM solution. The achieved scattering parameters and noise figure from the EM model are then compared with the measured results and those from a conventional RC parasitic extraction tool for evaluation. The simulated parameters, such as input and output return losses, power gain, reverse isolation, noise figure and noise resistance, as well as stability factor, exhibit excellent agreement with the results achieved from a characterized LNA chip. However, the post-layout optimization of LNA is based on a conventional RC parasitic extraction tool, which causes frequency-shifted measured results. The promising results confirm that the use of this method before fabrication significantly reduces the requirement of further re-fabrications for optimization and guarantees first-pass fabrication success for radio-frequency integrated circuits. This method has the feasibility of implementation for industrial application. Target is to avoid post-fabrication tuning or re-fabrication for discrepancy tuning.Die-level electromagnetic analysis for RF CMOS integrated circuits is studied.EM-simulated results are compared against the measured ones for 130-nm RF CMOS LNA.EM analysis showed higher correlation with characterization than conventional tools.

Modelling of a novel design of microfluidic based acoustic sensor

This paper reports the initial investigation on a novel acoustic sensor design based on micro fluidic technology. The report includes the proposed design structure and the simulation of key structure materials that affect the performance of such sensor. Simulation works included the analysis of acoustic response of the membrane and the damping effect when the cavity gap is filled with liquid or electrolyte material. For membrane analysis three different materials, silicon nitride (Si3N4), Teflon and Polydimethylsiloxane (PDMS) are simulated to obtain the most responsive material with respect to acoustic pressure signal. PDMS was found to be the most responsive material with the deflection sensitivity of 1.6 μm/Pa. Both Si3N4 and Teflon yielded a sensitivity of 0.034 μm/Pa and 0.67 μm/Pa respectively. In damping analysis, Propylene Carbonate electrolyte was used as a backing layer that filled the cavity gap. With the PDMS was selected as the membrane structure, harmonic analysis was performed to investigat the damping effect caused by electrolyte material on resonance frequency and deflection sensitivity. Result showed that with the proposed design structure and electrolyte backing layer, the harmonic frequency was shifted to a lower value with the maximum deflection was reduced by about 50%. The result also suggests the needs for selecting the right gap material for micro fluidic application that can compromise the damping and the response of the membrane.

I-V characteristic effects of fluidic-based memristor for glucose concentration detection

The I-V characteristic effect of thin film TiO2 fluidic-based memristor sensor utilized in sensing various glucose concentrations is described in this paper. Four different glucose concentrations, namely, 5, 10, 20, and 30 mM, are prepared and applied to the sensor. The device is then characterized with Keithley 4200-SCS semiconductor characterization system. Results show that different concentration levels of glucose affect the I-V characteristic of the sensor device. The difference is observed at the first voltage sweep of 0 V to 3 V after glucose was applied. A uniform change in current was recorded for small voltages below 0.9 V. The current decreases as the glucose concentration increases. Analysis shows that the resistance of the memristor sensor increases with the increase in glucose concentration through a quadratic relation.

Effect of heat treatment temperature and surface roughness to the PDMS-FR4 adhesive bonding

The current work investigates the use of liquid polydimethylsiloxane (PDMS), with a 10:1 ratio of prepolymer:curing agentu2009=u200910:1 as the intermediate layer for adhesive bonding with Flame Retardant 4 (FR4). The spin coating of liquid PDMS on FR4 allows irreversible adhesive bonding with the solid PDMS. The strength of the proposed adhesive bonding technique has been investigated under different treatment temperatures: oven-heated at 60u2009°C, 70u2009°C, and 80u2009°C, cooled down in the room temperature of 25u2009°C, and exposed to direct sunlight at 35u2009°C. All the samples were left for 6u2009h. Investigations were conducted to analyze the effect of FR4 surface roughness on the strength and quality of the adhesive bonding. The standard procedure of American Standard Test Measurement (ASTM) D1002 was followed to verify the strength of PDMS-FR4 adhesive bonding. Strongest adhesive bonding, free from air bubbles, was obtained from a sample with smooth surface of FR4 that has undergone a cooling down treatment in the room temperature of 25u2009°C. FR4 was coated by solder mask to obtain smooth surface. The techniques reported in this paper are simple, straightforward, and effective to be implemented with FR4 as a base material for adhesive bonding with PDMS, thus eliminating expensive and complicated operating equipment as widely used in the oxygen plasma-assisted bonding treatment. Another benefit from this adhesive bonding technique is the fact that it avoids the use of expensive oven or hot plate.

Flow analysis of microfluidic-based acoustic sensor

This work studied the behaviour of two different material candidates to be used as liquid for a microfluidic-based acoustic sensor. These liquid will be used as an electrolyte where the capacitive sensing mechanism is adopted. ANSYS was used to simulate the laminar flow of these materials inside the device. From the simulation, flow characteristics such as pressure distribution, velocity profile and flow response were obtained. Pressure distribution plot exposed the maximum pressure region where the flow was also maximum. The region was found to occur just at the starting point of the microchannel. Velocity profile indicated the velocity contour plot and flow direction based on the difference in pressure (represent the acoustic pressure) between the sensing membrane and the microchannel end. Finally, from the flow response, the performance of two different liquids was obtained and analysed. In terms of performance response to the applied pressure, Methanol showed a better response with approximately 18 times higher than Propylene Carbonate.

Design of Polyimide based Piezoelectric Micromachined Ultrasonic Transducer for Underwater Imaging Application

Micromachined ultrasonic transducer has been used in many application for example non-destructive test, medical diagnostic and underwater application. One of the underwater application is underwater acoustic imaging system. Underwater acoustic imaging system needs a transducer with wide bandwidth to perform high resolution image. In previous paper, Capacitance Micromachined Ultrasonic Transducer (CMUT) and Piezoelectric Micromachined Ultrasonic Transducer (PMUT) was studied in acoustic imaging. In this paper, PMUT was designed and studied their receiving sensitivity. The target operating frequency is in between 300 kHz to 700 kHz for underwater acoustic imaging. Simulation using Comsol 5.0 was used to determine the PVDF thickness, pitch element and substrates material, Polyimide and Silicon for desired frequency and high receiving sensitivity. In this paper, Polyimide was used as substrate rather than previous paper was used Silicon as substrate. The positive and ground electrode with lateral structure was fabricated onto Polyimide substrate. The polyvinylidene difluoride, (PVDF) used as sensing element was placed on top of electrodes to obtain polarization and with lateral structure of electrodes, PMUT will induced the d33 mode polarization. The Pulse-echo method was used in experiments to determine the receiving sensitivity. PMUT was obtained receiving sensitivity at -80.84 dB rev 1V/uPa with resonance frequency, 525 kHz. Low frequency for PMUT was obtained at 450 kHz and high frequency for PMUT was obtained at 650 kHz. Bandwidth for PMUT is 38.1%.

Characterization of ROFF/RON ratio of fluidic based memristor sensor for pH detection

This paper reports a new design for a memristor with an embedded channel to study the effect of liquids on ROFF/RON ratio. There were three types of liquid selected to represent all pH groups comprise of acidity, neutrality, and alkalinity. The liquids were added to the channel and the ROFF/RON ratio was calculated based on the I-V characteristics. The obtained ROFF/RON ratios showed a direct proportional relationship between ROFF/RON ratio and the pH value indicating the potential of this embedded channel memristor to be used as the most flexible ROFF/RON ratio memristor. The low ROFF/RON ratio of normal memristor at low voltage can be improved by adding alkaline liquid to the channel. The structure of the proposed memristor device is believed to be the simplest structure among the other similar sensors developed by other researchers.

A Fully-Integrated Dual-Band Concurrent CMOS LNA for 2.45/5.25 GHz Applications

This paper presents a fully-integrated dual-band concurrent CMOS low noise amplifier (LNA) which is implemented in Global Foundries 0.13 um RF CMOS technology. The LNA is designed to receive signals at 2.45 and 5.25 GHz frequency bands simultaneously. The concurrent operation of the proposed LNA makes it suitable for WLAN (802.11 b/g/a) applications. Based on post layout simulation results, this design achieved the power gain of 16 dB at 2.45 GHz and 11.7 dB at 5.25 GHz, the NF of 3 dB at 2.45 GHz and 4.3 dB at 5.25 GHz and the input and output return loss of −14 dB at the desired frequencies. Total power consumption of this design is only 6.5 mW.

200 kHz pMUT using PZT on PDMS membrane for sonar applications

An effort to enhance receiving response of piezoelectric micromachined ultrasonic transducer (pMUT) at low frequency is reported. PMUT is fabricated on the glass substrate with the vibrating membrane formed by a layer of polydimethylsiloxane (PDMS) polymer. Lead zirconate titanate, Pb(Zr, Ti)O3 (PZT) is utilized as the piezo-active layer and nickel as electrodes. Spin coating and low temperature wafer bonding are proposed as part of the key fabrication methods. Fabricated transducer is characterized in the compact acoustic tank setup using 500 kHz and 1.25 MHz reference projectors. Analyses reveal the resonance frequency of pMUT is at 200 kHz where maximum receiving response at −36.6 dB re 1V at 10 λ and 20 V peak to peak of drive voltage on reference projector. Finally, response spectrum of the transducer is plotted against two commercial hydrophones at equivalent frequency band for validation and comparison.

Vibration analysis of pMUT with polymer adhesion layer

Wafer bonding using polymer adhesive layer has gained many attentions for various MEMS applications. Numerous techniques and processes that utilize polymer adhesive have been established recently, mainly for wafer bonding and device packaging. However, adhesive layer contribution in vibrating micro structure such as micro ultrasonic transducer requires further investigations. This paper reports performance difference of piezoelectric micro ultrasonic transducer (pMUT) with polymer adhesion layer of PDMS, Cytop and Polyimide. Finite element analysis was utilized to analyze structure behavior during vibration. Frequency analysis revealed 41 kHz shift in devices resonant frequency when different type of polymers employed as adhesive layer. Further investigations through piezoelectric analysis found that PDMS has contributed in 40% decrease of voltage response than other two polymers at only 6×10−5 μm/V, but carry the highest stress response at 2×10−5 μm/Pa in both transmit and receive modes in mechanical analysis. Finally, same analysis cycle was conducted on pMUT structure with polymer adhesive layer being replaced by polysilicon at the same thickness.