Aging and health among migrants in a European perspective

Kristiansen M, Razum O, Tezcan-Güntekin H, Krasnik A. Aging and health among migrants in a European perspective. Public Health Reviews. 2016;37(1): 20

ACE Inhibition and Endothelial Function: Main Findings of PERFECT, a Sub-Study of the EUROPA Trial

Background: ACE inhibition results in secondary prevention of coronary artery disease (CAD) through different mechanisms including improvement of endothelial dysfunction. The Perindopril-Function of the Endothelium in Coronary artery disease Trial (PERFECT) evaluated whether long-term administration of perindopril improves endothelial dysfunction. Methods: PERFECT is a 3-year double blind randomised placebo controlled trial to determine the effect of perindopril 8 mg once daily on brachial artery endothelial function in patients with stable CAD without clinical heart failure. Endothelial function in response to ischaemia was assessed using ultrasound. Primary endpoint was difference in flow-mediated vasodilatation (FMD) assessed at 36 months. Results: In 20 centers, 333 patients randomly received perindopril or matching placebo. Ischemia-induced FMD was 2.7% (SD 2.6). In the perindopril group FMD went from 2.6% at baseline to 3.3% at 36 months and in the placebo group from 2.8 to 3.0%. Change in FMD after 36 month treatment was 0.55% (95% confidence interval −0.36, 1.47; p = 0.23) higher in perindopril than in placebo group. The rate of change in FMD per 6 months was 0.14% (SE 0.05, p = 0.02) in perindopril and 0.02% (SE 0.05, p = 0.74) in placebo group (0.12% difference in rate of change p = 0.07). Conclusion: Perindopril resulted in a modest, albeit not statistically significant, improvement in FMD

A low-cost uncooled infrared microbolometer detector in standard CMOS technology

This paper reports the development of a low-cost uncooled infrared microbolometer detector using a commercial 0.8 mum CMOS process, where the CMOS n-well layer is used as the infrared sensitive material. The n-well is suspended by front-end bulk-micromachining of the fabricated CMOS dies using electrochemical etch-stop technique in TMAH. Since this approach does not require any lithography or infrared sensitive material deposition after CMOS fabrication, the detector cost is almost equal to the CMOS chip cost. The n-well has a TCR of 0.5-0.7%/K, relatively low compared to state-of-the-art microbolometer materials; however, it has negligible 1/f noise due to its single crystal structure. The use of polysilicon interconnects on the support arms instead of metal reduces the overall pixel TCR to 0.34%/K, but provides a better performance due to improved thermal isolation. Measurements show that such a fabricated pixel with 74 mum x 74 mum pixel area provides a thermal conductance of 0.62 muW/K, a thermal time constant of 21 ms, a dc responsivity of 9250 V/W, and a detectivity of 2.0 x 10(9) cmHz(1)/(2)/W with a total noise of 0.82 muV for a 4 kHz bandwidth. Based on this pixel, a 16 x 16 prototype focal plane array (FPA) with 80 pm x 80 mum pixel size and 13% fill factor has been implemented, where built-in diodes are used to simplify array scanning, at the expense of reduced overall pixel TCR of 0.24%/K. The n-well microbolometer array with a simple readout scheme provides a responsivity of 2000 V/W, a detectivity of 2.6 x 10(8) cmHz(1)/(2)/W, and an estimated NETD of 200 mK at 0.5 Hz frame rate. Considering that this performance can be further improved with low noise readout circuits, the CMOS n-well microbolometer is a cost-effective approach to implement very low-cost uncooled infrared detector arrays with reasonable performance

A CMOS n-well microbolometer FPA with temperature coefficient enhancement circuitry

This paper reports the development of a low-cost CMOS microbolometer focal plane array with a new temperature coefficient enhancement readout circuit. We have recently reported an uncooled microbolometer detector that uses the CMOS n-well layer as the active material, where the suspended and thermally isolated n-well structure is obtained by silicon bulk micromachining of fabricated CMOS dies. In addition, we have successfully fabricated a 16x16 n-well microbolometer FPA. Although n-well is single crystal silicon and has very low 1/f noise, the fabricated array performance was limited due to low TCR of the n-well. The n-well. has a TCR of 0.50-0.70%/K, which is the highest among the CMOS layers, but lower compared to the state-of-the-art microbolometer materials whose TCR values are about 2-3%/K. This paper reports a new n-well microbolometer FPA with a readout circuit that enhances the temperature coefficient (TC) of the microbolometer current, compensating for the low TCR value of the detector. The TC enhancement is achieved by passing the pixel current through a 4(th) power taking circuit prior to integration, increasing the pixel current TC four times and resulting in an effective TC of 2.0-2.8%/K. A 16xl6 test array has been designed and fabricated using a 0.8mum standard CMOS process. The chip measures 2.4x3.8 mm(2) and contains 80mumx80mum microbolometer pixels with 13% fill factor. The measurements and calculations show that the 16xl6 prototype FPA can provide a responsivity (R) of 2x10(7)V/W, a detectivity (D*) of 1.68x10(9)cmrootHz/W, and NETD of 290mK at a scanning rate of 260fps. The same NETD value can be obtained for a 128x128 pixel array operating at 30fps. NETD can further be decreased by improving the noise performance of the readout circuit, since the performance is not limited by the n-well microbolometer noise

<title>Uncooled microbolometer infrared focal plane array in standard CMOS</title>

This paper reports implementation of a low-cost microbolometer focal plane array using n-well layer in a CMOS process as the microbolometer material. N-well microbolometer structures are suspended for thermal isolation by postetching of fabricated CMOS dies using silicon bulk-micromachining techniques. Although n-well has a moderate TCR of 0.5-0.65 %/K at 300 K, it still provides a reasonable performance due to its single crystal structure which contributes low 1/f noise. Detailed thermal simulations in ANSYS were performed to obtain an optimized structure. Various prototype FPAs with 16x16 array sizes have been implemented with 80 mu mx80 mum and 50 mu mx50 mum pixel sizes. The measurements and calculations show that the n-well microbolometers can provide a responsivity of 8.5x10(6) V/W, a detectivity of 5.5x10(9) cmHz(1/2)/W, and an NETD of 260 mK at 30 frames per second using a simple, fully-serial readout approach with an integrator output. The performance of the array can be increased with advanced readout techniques and improved pixel structures. The CMOS n-well microbolometer approach seems very cost-effective to produce large focal plane arrays for uncooled infrared imaging with reasonable performance

A low cost uncooled infrared microbolometer focal plane array using the CMOS n-well layer

This paper reports a low-cost, 256-pixel uncooled infrared microbolometer focal plane array (FPA) implemented using a 0.8 mum CMOS process where the n-well layer is used as the active microbolometer material. The suspended n-well structure is obtained by simple front-end bulk etching of the fabricated CMOS dies, while the n-well region is protected from etching by electrochemical etch-stop technique within a TMAH solution. Electrical connections to the suspended n-well are obtained with polysilicon interconnect layer instead of aluminum to increase the thermal isolation of the pixel by an order of magnitude. Since polysilicon has very low TCR and high resistance, the effective TCR of the pixel is reduced to 0.34%/K, even though the n-well TCR is measured to be 0.58%/K A 16x16 pixel array prototype with 80 mu mx80 mum pixel sizes has successfully been implemented. The pixel resistance measurements show that pixels are very uniform with a nonuniformity of 1.23%. Measurements and calculations show that the detector and the array provide a responsivity of 1200V/W, a detectivity of 2.2x10(8)cmHz(1/2)/W, and a noise equivalent temperature difference (NETD) of 200mK at 0.5Hz frame Tate with fully serial readout scheme. This performance can be further increased by using other advanced readout techniques, therefore, the CMOS n-well microbolometer approach seems to be a very cost-effective method to produce large focal plane arrays for low-cost infrared imaging applications

Low-cost uncooled infrared detectors in CMOS process

This paper reports the implementation and comparison of two low-cost uncooled infrared microbolometer detectors that car be implemented using standard n-well CMOS processes. One type is based on a suspended n-well resistor, which is implemented in a 0.8 mum CMOS process and has a pixel size of 80 mum x 80 mum with a fill factor of 13%; and the other type is based on a suspended p(+)-active/n-well diode, which is implemented in a 0.35 mum CMOS process and has a pixel size of 40 mum x 40 mum with a fill factor of 44%. These detectors can be obtained with simple bulk-micromachining processes after the CMOS fabrication, without the need for any complicated lithography or deposition steps. The diode type detector has a measured dc responsivity (R) of 4970 V/W at 20 muA bias and a thermal time constant of 35.8 ms at 80 mTorr vacuum level, and it has a measured rms noise of 0.52 muV for a 4 kHz bandwidth, resulting in a detectivity (D*) of 9.7 x 10(8) cm Hz(1 /2)/W. The resistive n-well detector can provide the same dc responsivity at 1.68 V detector bias voltage, with about 10 times more self-heating as compared to that of the diode type detector. This detector has a measured rms noise of 0.81 RV for a 4 kHz bandwidth, resulting in a detectivity (D*) of 8.9 x 10(8) cm Hz(1/2)/W, which can be improved further with higher detector bias voltages at the expense of increased self-heating. The diode type detector is better for low-cost large format infrared detector arrays, since it has a superior response even at reduced pixel sizes and lower biasing levels

A low-cost small pixel uncooled infrared detector for large focal plane arrays using a standard CMOS process

This paper reports the development of a low-cost, small pixel uncooled infrared detector using a standard CMOS process. The detector is based on a suspended and thermally isolated p(+)-active/n-well diode whose forward voltage changes due to an increase in the pixel temperature with absorbed infrared radiation. The detector is obtained with simple post-CMOS etching steps on dies fabricated using a standard n-well CMOS process. The post-CMOS process steps are achieved without needing any deposition or lithography, therefore, the cost of the detector is almost equal to the cost of the fabricated CMOS chip. Before suspending the pixel using electrochemical etch-stop technique in TMAH, the required etch openings to reach the silicon substrate are created with a simple dry etch process while CMOS metal layers are used as protection mask. Since the etch mask is implemented with available CMOS layers, the etch openings can be reduced significantly, allowing to implement small pixel sizes with reasonable fill factor. This approach is used to implement a 40mumx40mum diode pixel with a fill factor of 44%, suitable for large format FPAs. The p(+)-active/n-well diode has a low 1/f noise, due to its single crystal nature and low bias requirement. Optimum pixel performance is achieved when the pixel is biased at 20muA, where self-heating effect is less than 0.5K. Measurements and calculations show that this new detector has a thermal conductance (G(th)) of 1.4x10(-7)W/K and provides a responsivity (R) of 5800V/W and a detectivity (D) value of 1.9x10(9)cm Hz/W when scanned at 30fps with an electrical bandwidth of 4kHz. If this detector is used to implement a 64x64 or 128x128 FPA with sufficient number of parallel readout channels, these FPAs will provide an NETD value of 195mK considering only the detector noise. When the readout noise is included, these FPAs are expected to provide NETD value below 300mK. Such FPAs are very suitable for ultra low-cost infrared imaging applications