On-chip Heater Research Articles

Sub-millisecond timing-jitter-free tuning of parametric dispersion compensator

We demonstrate sub-millisecond tuning of a prototype parametric tunable dispersion compensator (P-TDC) based on cascaded polarization-diverse four-wave mixing (FWM) process with a fast tunable and highly wavelength-stable pump light source. The pump light source is developed using a tunable distributed amplification chirped sampled grating distributed reflector laser that is fully wavelength tunable by on-chip heaters with a 3-dB frequency response of 45 kHz, resulting in fast dispersion tuning of less than 50 μs without additional timing jitter. The P-TDC is developed as the first prototype to satisfy essential requirements for practical network uses: stable input-polarization diversity, input-wavelength preservation, and seamless dispersion tunability for entire C-band input wavelengths are simultaneously achieved.

Two-Port Static Coated Micro Gas Chromatography Column With an Embedded Thermal Conductivity Detector

This paper reports a microfabricated 2×4 cm gas chromatography chip to separate and detect gases in a two-port structure by embedding a microthermal conductivity detector (μTCD) within a separation column. A circular on-chip heater is placed on the backside of the monolithic device enabling temperature programming and consequently faster analysis of the heavier components. A unique process enhanced by reactive ion etching lag (RIE lag) is used to achieve multiple etch depths in silicon and restrict the process flow to just three masks. The silicon substrate contains the separation column, the heater, and the tunnels for the TCD electric feed throughs. A Pyrex wafer containing the TCD elements is anodically bonded to the silicon substrate to seal the structure. Performance of a standalone μTCD fabricated in the same process and integrated in a hybrid fashion is also described. The single-chip design demonstrates successful separation and identification of multi-component gas mixtures with a performance comparable to that obtained through a flame ionization detector connected in series. Further, on-chip temperature programming capability was utilized to elevate the column temperature to 75 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C to exhibit analysis in less than a minute.

Fabrication and experimental demonstration of the first 160 Gb/s hybrid silicon-on-insulator integrated all-optical wavelength converter

We present a hybrid integrated photonic circuit on a silicon-on-insulator substrate that performs ultra high-speed all-optical wavelength conversion. The chip incorporates a 1.25 mm non-linear SOA mounted on the SOI board using gold-tin bumps as small as 14 μm. Τhe device performs chirp filtering and signal polarity inversion with two multi-mode interference (MMI) - based cascaded delay interferometers (DIs) monolithically integrated on the same SOI substrate. Full free spectral range (FSR) tuning of the DIs is accomplished by two independently tuneable on-chip thermal heaters. We demonstrate 160Gb/s all-optical wavelength conversion with power penalties of less than 4.6dB.

Simultaneous Characterization of Theta-JC and Theta-JB Using Through-Package 1-D Heat Flow

A new technique is proposed for simultaneous, in-situ characterization of in-package thermal resistances (junction-to-case and junction-to-board) in a single test. A thin resistive heater is patterned on package top surface to establish one-dimensional heat conduction along the package vertical direction. Accompanying temperature rise at the heater is measured using a thermocouple and analyzed to estimate equivalent thermal R-C network model of the package. Due to the one-dimensionality of the probing thermal wave, the derived R-C network model represents physical package thermal structure, enabling simultaneous estimation of both thermal resistances (theta-JC and theta-JB). The proposed technique is validated by measuring theta-JC and JB of an overmolded flip-chip ball grid array package. The proposed method eliminates need for a separate test setup for the characterization of each thermal resistance, enhancing the accuracy and efficiency of the package thermal characterization. In addition, use of the external heater and sensing element, instead of on-chip heater and temperature sensor, enables in-situ thermal characterization of a real package mounted on the set board.

Output Level Control of SOA Using On-Chip Heater for High Output Power Operation

A novel gain control scheme of semiconductor optical amplifiers (SOAs) using a heater-mounted SOA was investigated. In our proposal, a simple SOA gain control using an on-chip heater provides a high saturation output power over an entire gain control range of 10 dB. This scheme widely expands the usable power range in output level control of a 10 Gbps NRZ-OOK signal, compared to that of a conventional gain control operated by drive current. As a result, the heater-mounted SOA exhibited a large input power dynamic range (IPDR) of > 17 dB up to the output power of +8.0 dBm in level control operation.

A Polymer-Based Microfluidic Platform Featuring On-Chip Actuated Hydrogel Valves for Disposable Applications

present a highly functional polymer-based microfluidic device for disposable applications. This device is plastic injection molded and exhibits three levels of functionality: 1) fluidic interconnects are monolithically integrated with the device, enabling robust manufacturing and high-pressure operation (> 3.5 MPa); 2) a metal layer is lithographically patterned in the form of microheaters; and 3) a thermally sensitive hydrogel valve is integrated into the channel. The valve is normally closed at room temperature. Upon heating to above the lower critical solution temperature of 32°C, the polymer valve becomes hydrophobic, shrinks while forming large pores, and permits flow. The device has been actuated reliably over 100 times with no apparent degradation. The valve closing response using the integrated on-chip heaters is 5 s, as opposed to 20 s when using off-chip heat sources. On average, a completed device can be fabricated in less than 2 h and only requires an external pressure source and electrical controller for operation.

Tunable and rotatable polarization controller using photonic crystal fiber filled with liquid crystal

We design and fabricate a compact tunable and rotatable polarization controller using liquid crystal photonic band gap fibers. The electrically and thermally induced phase shift in the Poincaré sphere and corresponding birefringence change are measured. The direction of the electric field is managed by connecting four electrodes in different electrode configurations, and the thermal tunability is controlled by on-chip heaters. According to the results, a quarter-wave plate and a half-wave plate working in the wavelength range of 1520–1600 nm are experimentally demonstrated.

Submilliwatt thermo-optic switches using free-standing silicon-on-insulator strip waveguides

A low power Mach-Zehnder interferometer thermo-optic switch using free-standing silicon-on-insulator strip waveguides is demonstrated. The air gap provides thermal isolation between the waveguide interferometer arms and the underlying silicon substrate. The highly confined optical modes of the strip waveguides enable miniature heated cross-sections. The heating efficiency from on-chip resistive heaters is enhanced. Measurements of fabricated devices using 100 microm arm lengths at 1550 nm wavelength result in a switching power of 540 microW, a 10% - 90% switching rise time of 141 micros, and an extinction ratio of 25 dB.

Phase separation in polymer blend thin films studied by differential AC chip calorimetry

AC chip calorimetry is used to study the phase separation behavior of 100 nm thin poly(vinyl methyl ether)/poly(styrene) (PVME/PS) blend films. Using the on-chip heaters, very short (10 ms–10 s) temperature jumps into the temperature window of phase separation are applied, simulating laser heating induced patterning. These temperature pulses produce a measurable shift in the glass transition temperature, evidencing phase separation. The effect of pulse length and height on phase separation can be studied. The thus phase separated PVME/PS thin films remix rapidly, in contrast with measurements in bulk. AC chip calorimetry seems to be a more sensitive technique than atomic force microscopy to detect the early stages of phase separation in polymer blend thin films.

A microfluidic affinity sensor for the detection of cocaine

We present a microfluidic aptamer-based biosensor for specific cocaine detection. The device consists primarily of a microchamber packed with aptamer-functionalized microbeads that act as a sensing surface, integrated with an on-chip heater and temperature sensor. The sensor employs a Förster resonance energy transfer (FRET) system in which a fluorophore-quencher pair of carboxyfluorescein and Dabcyl generates a signal-on response to cocaine. We demonstrate device operation by successfully detecting cocaine with a four orders of magnitude linear response in micromolar to nanomolar concentrations. The detection limit of the device is further lowered to 10 pM by concentration of a highly diluted cocaine sample, which compares well with the most sensitive detection techniques currently available. The temperature-dependent binding of aptamer–analyte complexes is then used to effect thermal release of cocaine from the sensing surface. It is found that a temperature of 37 °C can fully regenerate the sensor in pure buffer. Furthermore, testing indicated that sensor response is consistent after repeated regeneration. These results demonstrate that aptamer-based sensing on a microfluidic platform has the potential to enable low-cost, rapid, and highly specific detection of cocaine in practical applications.

Micro-hotplate based temperature stabilization system for CMOS SAW resonators

Due to the sensitivity of the piezoelectric layer in surface acoustic wave (SAW) resonators to temperature, a method of achieving device stability as a function of temperature is required. This work presents two methods of temperature control for CMOS SAW resonators using embedded polysilicon heaters. The first approach employs the oven control temperature stabilization scheme. Using this approach, the device’s temperature is elevated using on-chip heaters to Tmax = 42°C to maintain constant device temperature. Both DC and RF measurements of the heater together with the resonator were conducted. Experimental results have indicated that the TCF of the CMOS SAW resonator of −97.2 ppm/°C has been reduced to −23.19 ppm/°C when heated to 42°C. The second scheme uses a feedback control circuit to switch the on-chip heaters on and off depending on the ambient temperature. This method provided reduction of the TCF from −165.38 ppm/°C, to −93.33 ppm/°C. Comparison of both methods was also provided.

High-speed, temperature programmable gas chromatography utilizing a microfabricated chip with an improved carbon nanotube stationary phase

A new growth recipe for producing carbon nanotubes (CNTs) combined with a new bonding technique was implemented in a microfabricated gas chromatography (micro-GC) chip. Specifically, the micro-GC chip contained a 30-cm (length) microfabricated channel with a 50 μm × 50 μm square cross-section. A CNT stationary phase “mat” was grown on the bottom of the separation channel prior to the chip bonding. Injections onto the micro-GC chip were made using a previously reported high-speed diaphragm valve technique. A FID was used for detection with a high-speed electrometer board. All together, the result was a highly efficiency, temperature programmable (via low thermal mass, rapid on-chip resistive heating) micro-GC chip. In general, the newly designed micro-GC chip can be operated at significantly lower temperature and pressure than our previously reported micro-GC chip, while producing excellent chemical separations. Scanning electron microscopy (SEM) images show a relatively thin and uniform mat of nanotubes with a thickness of ∼800 nm inside the channel. The stationary phase was further characterized using Raman spectroscopy. The uniformity of the stationary phase resulted in better separation efficiency and peak symmetry (as compared to our previous report) in the separation of a mixture of five n-alkanes ( n-hexane, n-octane, n-nonane, n-decane and n-undecane). The on-chip resistive heater employing a temperature programming rate of 26 °C/s produced a peak capacity of eight within a 1.5-s time window.

Real-time forensic DNA analysis at a crime scene using a portable microchip analyzer

An integrated lab-on-a-chip system has been developed and successfully utilized for real-time forensic short tandem repeat (STR) analysis. The microdevice comprises a 160-nL polymerase chain reaction reactor with an on-chip heater and a temperature sensor for thermal cycling, microvalves for fluidic manipulation, a co-injector for sizing standard injection, and a 7-cm-long separation channel for capillary electrophoretic analysis. A 9-plex autosomal STR typing system consisting of amelogenin and eight combined DNA index system (CODIS) core STR loci has been constructed and optimized for this real-time human identification study. Reproducible STR profiles of control DNA samples are obtained in 2 h and 30 min with ≤0.8 bp allele typing accuracy. The minimal amount of DNA required for a complete DNA profile is 100 copies. To critically evaluate the capabilities of our portable microsystem as well as its compatibility with crime scene investigation processes, real-time STR analyses were carried out at a mock crime scene prepared by the Palm Beach County Sheriff's Office (PBSO). Blood stain sample collection, DNA extraction, and STR analyses on the portable microsystem were conducted in the field, and a successful “mock” CODIS hit was generated on the suspect's sample within 6 h. This demonstration of on-site STR analysis establishes the feasibility of real-time DNA typing to identify the contributor of probative biological evidence at a crime scene and for real-time human identification.

Multichannel Reverse Transcription-Polymerase Chain Reaction Microdevice for Rapid Gene Expression and Biomarker Analysis

A microdevice is developed for RNA analysis that integrates one-step reverse transcription and 30 cycles of PCR (RT-PCR) amplification with capillary electrophoresis (CE) separation and fluorescence detection of the amplicons. The four-layer glass-PDMS-glass-glass hybrid microdevice integrates microvalves, on-chip heaters and temperature sensors, nanoliter reaction chambers (380 nL), and 5-cm-long CE separation channels. The direct integration of these processes results in attomolar detection sensitivity (<11 template RNA molecules or approximately 0.1 cellular equiv) and rapid 45-min analysis, while minimizing sample waste and eliminating contamination. Size-based electrophoretic product analysis provides definitive amplicon-size verification and multiplex analysis. Multiplexed differential gene expression analysis is demonstrated on mdh and gyrB E. coli transcripts. RNA splice variant analysis of the RBBP8 gene is used to identify tumorigenic tissue. RT-PCR microdevice analysis of normal breast tissue RNA generates the expected 202-bp normal splice isoform; tumor breast tissue RNA samples generate a 151-bp amplicon signifying the presence of the tumorigenic splice variant. The ability to perform RNA transcript and splice variant biomarker analysis establishes our RT-PCR microdevice as a versatile gene expression platform.

A latchable microvalve using phase change of paraffin wax

This paper presents a novel latchable phase-change microvalve that can potentially be used for flow gating in portable lab-on-a-chip systems where minimal energy consumption is desired. The microvalve innovatively exploits paraffin wax of low melting point, whose solid–liquid phase changes allow the closing and opening of fluid flow through deformable microchannel ceiling. The latchable phase-change actuation scheme can be used in an active valve to shut off and open fluid flow. Valve switching is initiated by melting of paraffin through heating, with an additional pneumatic pressure used for valve switching from open to closed state. Energy consumption is only required during the valve switching. After paraffin solidifies the switched state is subsequently maintained passively without further consumption of energy. The microvalve can be fabricated from PDMS through the multilayer soft lithography technique. Testing results demonstrate that the valve has response times of 60 s for closing and 100 s for opening; when closed, the valve can passively withstand a pressure up to 35 kPa without significant leakage. The relatively slow time response of the proof-of-concept device can be readily improved by integrating on-chip heaters, while the latchability of the microvalve can be improved by optimizing the wax chamber and membrane design. Compared to existing latchable phase-change valves, the thin compliant channel ceiling of the valve separates the fluid channel from the wax chamber. Therefore, the microvalve is free of potential contamination of the fluid by the paraffin wax. In addition, the improved sealing offered by the compliant membrane makes the valve robust and flexible in operation, allowing large ranges of initiation pressure generated from various actuation schemes.

Methanol Steam Reformer on a Silicon Wafer

A study of the reforming rates, heat transfer and flow through a methanol reforming catalytic microreactor fabricated on a silicon wafer are presented. Packed bed microchannel reactors were fabricated using silicon DRIE, followed by wafer bonding. The reactor bed was subsequently filled with catalyst particles. Thermal control is achieved through on-chip resistive heaters, whereby methanol steam reforming reactions were studied over a temperature range from 180-300 degC. Three simulations of varying complexity, including three-dimensional (3-D), quasi-3-D, and 1-D models, were developed. Comparison of the models with experimental results shows good agreement over a range of operating conditions. We found that Amphlett's kinetics for methanol reforming provided accurate results, and that for our operating conditions the reforming reaction could be modeled without mass transport considerations. The 1-D model provided a rapid analytical tool to assess the performance of the microreactor. Use of such computationally efficient design tools provides an effective means to analyze the performance of microreactor designs prior to fabrication and test. Hence, reformer geometry, catalyst loading, and operating parameters can be optimized to afford the desired hydrogen output and conversion. Concepts for insulating the reactor while maintaining small overall size are further analyzed

Enzymatic Activity Measurement at High Temperature by Pulse Heating of Micro Reactor with On-Chip Micro Heater

The activity of an enzyme, captured in a micro chamber array, at elevated temperature has been successfully measured thanks to the rapid temperature control enabled by an on-chip micro heater. The enzyme, β-Galactosidase, survived short exposure (4 seconds) to high temperature at which it was severely damaged by longer exposure. Its activity at the higher temperature (around 60°C) was shown to be 4.2 times greater than that at 23°C. Furthermore, the degree of accelerated activity is expected to be controlled by changing the frequency of the heat pulses.

FLIP-CHIP PACKAGED MICRO-PLATE FOR LOW COST THERMAL MULTIPLEXING

International Journal of Computational Engineering ScienceVol. 04, No. 02, pp. 235-238 (2003) BioMEMS and MicrofluidsNo AccessFLIP-CHIP PACKAGED MICRO-PLATE FOR LOW COST THERMAL MULTIPLEXINGYUBO MIAO, CHONG SER CHONG, TAICHONG CHAI, YU CHEN, QUANBO ZOU, TIE YAN, CHEW KIAT HENG, and TIT MENG LIMYUBO MIAOInstitute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore Search for more papers by this author , CHONG SER CHONGInstitute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore Search for more papers by this author , TAICHONG CHAIInstitute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore Search for more papers by this author , YU CHENInstitute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore Search for more papers by this author , QUANBO ZOUInstitute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore Search for more papers by this author , TIE YANThe National University of Singapore, Lower Kent Ridge Road, 14 Science Drive 4, Singapore 117543, Singapore Search for more papers by this author , CHEW KIAT HENGThe National University of Singapore, Lower Kent Ridge Road, 14 Science Drive 4, Singapore 117543, Singapore Search for more papers by this author , and TIT MENG LIMThe National University of Singapore, Lower Kent Ridge Road, 14 Science Drive 4, Singapore 117543, Singapore Search for more papers by this author https://doi.org/10.1142/S1465876303000971Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractIn this work, a low cost micro-plate array is developed using flip-chip technique for thermal multiplexing. The microplate is made of silicon chip with on-chip heater and temperature sensor for accurate control of temperature. These silicon chips are flip-chip bonded on a printed-circuit-board (PCB) and arranged in array for thermal multiplexing. By proper thermal design, high performance of thermal cycling has been achieved in this work. The micro-plate array has been used with a plastic chip together as multichamber micro-polymerase chain reaction (uPCR), which can perform independent protocol in each chamber simultaneously.Keywords:flip-chip bondingmicro-plate arraythermal multiplexinguPCR References M. Allen Northrup, DNA amplification with a microfabricated reaction chamber, 7th Intl. conf. Solid-state sensors and actuators, (1993) 924–926 . Google Scholar Baier Volker, et al, Miniaturized multi-chamber thermocycler, US patent 5939312 (1999) . Google Scholar Quanbo Zou et al, A microfabricated integratable thermal reactor, IEDM 2001, WS (2001) s16p9 . Google Scholar Quanbo Zou et al, Miniaturized multi-chamber thermal cycler, US patent 6521447, (2003) . Google Scholar FiguresReferencesRelatedDetails Recommended Vol. 04, No. 02 Metrics History Keywordsflip-chip bondingmicro-plate arraythermal multiplexinguPCRPDF download

Thermostatic control for temperature compensation of a silicon pressure sensor

An alternative temperature compensation technique for a silicon pressure sensor is presented. By using on-chip heater and temperature sensing electrodes, a thermostatic control loop is implemented. The sensor is biased at a reference temperature, which is maintained with high accuracy over a specified range, hereby eliminating the dependence of the pressure sensor output on ambient temperature. No additional calibration procedures for temperature compensation or external temperature sensing elements are required. Modelling aspects as well as experimental results are discussed.

Calibration of an integrated hydrogen gas-sensing system

An accurate and flexible calibration model has been developed for a single-chip integrated hydrogen-sensing system. The model continuously provides the hydrogen concentration from measurements of the palladium-nickel film resistor, which serves as the active gas-sensing structure, and an on-chip thermometer. Calibration parameters are easily determined from simple measurements that utilize temperature control provided by on-chip heaters. The model is shown to yield accurate results in practical environments, i.e., where time-dependent temperatures and hydrogen concentrations coexist. The model enables the implementation of small practical hydrogen-sensing systems based on an integrated hydrogen-sensing chip.