Browsing by Author "Chiu, Yi"

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A 0.20-V to 0.25-V, Sub-nW, Rail-to-Rail, 10-bit SAR ADC for Self-Sustainable IoT Applications
(2018-01-01)
Hong, Hao-Chiao
;
Chiu, Yi
;
電機工程學系
;
Department of Electrical and Computer Engineering
This paper presents a 10-bit SAR ADC operating at a supply voltage (VDD) of 0.225 V and down to 0.2 V for self-sustainable IoT applications. We propose an ultra-low VDD temperature-compensated bias current generator for biasing the comparator against temperature variation to address the temperature-dependent issue of the MOSFETs operating in the subthreshold region. In addition, the design fixes the positive input terminal of the comparator at VDD to bias the input transistor pair of the comparator with a sufficient voltage headroom at such a low VDD. The double-boosted with leakage reduction sampling switch is also proposed to address the severe leakage issue at low sampling rates. A test chip has been fabricated in 180-nm CMOS. The ADC core occupies only 0.024 mm(2). Measurement results show that at 0.225V, the DNL and INL are within +1.04/-0.66 and +0.97/-1.04 LSB in the rail-to-rail input range, respectively. The measured peak SNDR with the Nyquist input frequency is 49.8 dB at 450 S/s and 0.225V. The whole ADC totally consumes 0.85 nW at 0.225 V including the circuit leakages. It corresponds to an FoM of 8.0 fJ/conv.-step.
A CMOS-MEMS Thermoresistive Micro Calorimetric Flow Sensor With Temperature Compensation
(2019-10-01)
Xu, Wei
;
Ma, Shenhui
;
Wang, Xiaoyi
;
Chiu, Yi
;
Lee, Yi-Kuen
In this paper, we propose a new 1D thermoresistive micro calorimetric flow (TMCF) sensor model for moist airflow with the temperature-dependent thermophysical properties. The 1D model and the corresponding proposed equivalent circuit model enable rapid design optimization of an ambient temperature-compensated TMCF ((TMCF)-M-2) sensor integrated with the interface circuit by using a commercial 0.35-mu m 2P4M CMOS MEMS technology. The fabricated sensor shows a prominent sensitivity of 0.543 V/(m/s) and a low power consumption of less than 2.8 mW. Moreover, in comparison with the large drifting of 49% for the uncompensated TMCF sensor, the (TMCF)-M-2 sensor's output has an ultralow drifting of 0.5% with the ambient temperature variation of 22 degrees C similar to 48 degrees C. Therefore, this robust (TMCF)-M-2 sensor can be a promising Internet of Things (IoT) for smart energy-efficient buildings.
A Cost-Effective Angle Demodulator IC for Path Matched Differential Interferometry Based Sensors
(2014)
Hong, Hao-Chiao
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Chen, Yun-Tse
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Hung, Shao-Feng
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Wu, Chin-Cheng
;
Chiu, Yi
The angle demodulator (ADM) is a key component for the path matched differential interferometry (PMDI) sensors. Conventional ADMs require tens of operational amplifiers (OPAMPs) and bulky capacitors and resistors, making them diflicult to be realized as integrated circuits (ICs). This paper presents the first ADM IC design that requires only one OPAMP and thus saves significant area and power. In addition, this novel ADM design tolerates a wide range of modulation depth of the optical interferometer of the PMDI sensors. As a result, the yield of the PMDI sensor significantly increases. A test chip has been designed and successfully verified in 0.18-mu m CMOS. The active area of the proposed circuits is only 476 by 368 mu m(2) and it consumes only 6.26 mW.
A novel self-aligned process between a nano-aperture and a solid immersion lens for a near-field optical system
(2006-12-01)
Hsu, Hung-Lung
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Chang, Yu-Ru
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Chiu, Yi
;
Lin, Yu-Hsin
;
Hsu, Wensyang
For near-field optical systems, an aperture in nano-size and a solid immersion lens (SIL) are two popular methods to overcome the diffraction limit and reduce the optical spot size. In previous research, combining a nano-aperture and SIL has been proposed to provide high throughput and ultra-high resolution. However, alignment between the nano-aperture and SIL is very critical in the fabrication process, and no effective alignment technique has been investigated yet. In this research, a novel self-alignment technique is proposed for the combination of the nano-aperture and SIL, where the nano-aperture is fabricated with the focused ion beam (FIB) system and the SIL is formed by the thermal reflowing process. The self-alignment technique is based on the backside exposure and the surface tension self-modulation technique during the thermal reflowing process. The maximum deviation of the fabricated SIL is less than 3% in comparison with the designed values. A SIL of 15 mu m diameter has been measured with 65.2% transmission efficiency. The polymer SIL combined with the circular aperture of 329 nm diameter has 1.68 times enhancement on throughput compared with the circular aperture of 329 nm alone. This result shows that the SIL can effectively enhance the throughput of the nano-aperture, and the feasibility of the proposed self-alignment method is also verified.
A photovoltaic pn junction micro vertical comb-drive actuator
(2010-10-01)
Huang, Hsin-Yu
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Hsu, Hsiu-Ting
;
Lin, Hung-Yi
;
Chiu, Yi
;
Fang, Weileun
This study reports a novel micro electrostatic vertical comb-drive actuator (VCA) driven by the photovoltaic effect that results from incident light. The vertical comb electrodes have a pn junction structure (named pn-combs). The VCA with pn-combs can be driven by the photovoltaic effect. The combination of the photovoltaic effect and reverse bias can further increase the driving amplitude of the VCA. To demonstrate the feasibility of the proposed concept, the VCA with pn-combs was fabricated on an epitaxial silicon wafer (epi-wafer) and successfully driven resonantly by intensity-modulated laser light. The first torsional mode of a typical fabricated VCA is at 1.46 kHz. Moreover, VCA driven using (1) optical driving, and (2) optical driving with dc reverse bias, were also demonstrated. The angular displacement of the VCA was +/- 3.8 m deg by optical driving. The angular displacement of the VCA significantly increased to +/- 41 m deg after applying an additional dc reverse bias of 5 V.
A Robust Fully-Integrated Digital-Output Inductive CMOS-MEMS Accelerometer with Improved Inductor Quality Factor
(2019-11-01)
Chiu, Yi
;
Liu, Hsuan-Wu
;
Hong, Hao-Chiao
;
電機工程學系
;
Department of Electrical and Computer Engineering
This paper presents the design, fabrication, and characterization of an inductive complementary metal oxide semiconductor micro-electromechanical systems (CMOS-MEMS) accelerometer with on-chip digital output based on LC oscillators. While most MEMS accelerometers employ capacitive detection schemes, the proposed inductive detection scheme is less susceptible to the stress-induced structural curling and deformation that are commonly seen in CMOS-MEMS devices. Oscillator-based frequency readout does not need analog to digital conversion and thus can simplify the overall system design. In this paper, a high-Q CMOS inductor was connected in series with the low-Q MEMS sensing inductor to improve its quality factor. Measurement results showed the proposed device had an offset frequency of 85.5 MHz, sensitivity of 41.6 kHz/g, noise floor of 8.2 mg/root Hz, bias instability of 0.94 kHz (11 ppm) at an average time of 2.16 s, and nonlinearity of 1.5% full-scale.
A Three-Axis Single-Proof-Mass CMOS-MEMS Piezoresistive Accelerometer with Frequency Output
(2014)
Chiu, Yi
;
Huang, Tsung-Chih
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Hong, Hao-Chiao
;
電機資訊學士班
;
Undergraduate Honors Program of Electrical Engineering and Computer Science
Accelerometers have been used in a wide range of applications such as automobiles, mobile phones, and game controllers. In this paper, we present a monolithic complementary metal-oxide-semiconductor micro-electromechanical systems (CMOS-MEMS) accelerometer with frequency output. The output oscillation frequency can be converted to a digital code by using a counter so that the sensor can be easily integrated with digital signal processing units on the same chip. The accelerometer is composed of a single proof mass suspended by four suspension beams. Polysilicon piezoresistors are placed at the ends of the beams to sense the displacement of the proof mass. The piezoresistors are used in RC oscillators whose oscillation frequencies vary owing to the change in resistance upon application of an external acceleration. Acceleration components in three axes can be obtained by the proper combination of signals from the piezoresistors at different locations. The accelerometer was fabricated by standard CMOS processes followed by backside and frontside dry etching postprocessing. The measured mechanical resonant frequency is 464 Hz. The oscillation frequency of the z-axis oscillator is about 70 MHz. The measured absolute sensitivity, relative sensitivity, and resolution along the z-axis are 198 kHz/g, 2.8x10(-3) Delta f/f(0)/g, and 10.9 mG/root Hz, respectively, for a sampling rate of 400 Hz and acceleration of 6 g at 27 Hz.
A Wireless Gauge Pressure Sensor with Enhanced Sensitivity Fabricated by Flexible PCB Technology For Intracranial Pressure Sensing
(2019-01-01)
Chiu, Yi
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Chen, You-Zen
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Hsieh, Chia-Chun
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Hong, Hao-Chiao
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分子醫學與生物工程研究所
This paper presents a gauge pressure sensor based on the standard industrial flexible PCB (FPCB) technology. The wireless LC-resonant sensor consists of a variable sensing capacitor and a planar inductor coil fabricated in FPCB. The air gap of the sensing capacitor is extended through a pressure channel embedded in the FPCB strip to enable relative pressure measurement. Thus, the intracranial pressure (ICP) with respect to local atmosphere can be measured without other calibration means. The flat FPCB structure also facilitates the subdural implantation procedures. Experimental results showed that the proposed gauge pressure sensors with such open sensing structures had much higher frequency sensitivity (0.29%/mmHg) compared with sensors with sealed sensing cavities (0.005%/mmHg) and achieved a resolution of 0.51 mmHg.
An Angle Demodulator IC Using Periodically Reset Integration for Path Matched Differential Interferometry-Based Sensors
(2016-06-15)
Hong, Hao-Chiao
;
Chen, Yun-Tse
;
Hung, Shao-Feng
;
Wu, Chin-Cheng
;
Chiu, Yi
The angle demodulator (ADM) is a key component for sensors based on angle modulation such as in the path matched differential interferometry (PMDI). Conventional ADMs require tens of operational amplifiers (OPAMPs) and bulky capacitors and resistors, making them difficult to be realized as integrated circuits (ICs). Furthermore, the state-of-the-art ADMs demand precisely controlled modulation indices. Thus, the practical optical modulators in the interferometers cannot but need sophisticated and costly calibrations to precisely control the modulation indices. This paper presents the first ADM IC designed for the PMDI-based sensors. It requires only one OPAMP and thus saves significant area and power, making it best suitable for portable applications. In addition, this novel ADM design tolerates a wide range of the modulation depth of the optical interferometer. As a result, the yield of the PMDI sensor significantly increases and no calibration for an accurate modulation index is necessary. A test chip of the proposed ADM has been designed and successfully verified in 0.18-mu m CMOS. The active area of the proposed circuits is only 476 x 368 mu m(2) and it consumes only 6.26 mW.
Assembly of Micro Mirrors on SOI Wafers Using SU-8 Mechanisms and One-Push Operation
(2008)
Chiu, Yi
;
Huang, Wei-Zhi
;
Wu, Jhong-Wei
;
Chiou, Jin-Chem
;
Shieh, Han-Ping D.
Micro mirrors are assembled on silicon-on-insulator wafers using one-push operation. The proposed technique can reduce the overall complexity of micro system assembly by using automated equipments. Novel SU-8 mechanisms are also demonstrated.
Assembly of Micro-3-D Components on SOI Wafers Using Novel SU-8 Locking Mechanisms and Vertical One-Push Operation
(2009-09-01)
Chiu, Yi
;
Wu, Chang-Shiou
;
Huang, Wei-Zhi
;
Wu, Jhong-Wei
;
電控工程研究所
A novel out-of-plane assembly technique of 3-D microstructures is proposed and demonstrated by using simple vertical one-push operations. This one-push method has large probe positioning tolerance in both vertical and lateral directions to reduce the overall complexity of the assembly process. Micromirrors and corner cube reflectors are fabricated on silicon-on-insulator wafers using SU-8 photoresist as a second structure layer in a low-temperature process. Batch assembly of multiple mirrors assembled simultaneously is demonstrated.
Astigmatic diffractive optical element for swing-arm-type optical pickup head
(2009-07-01)
Lee, Chi-Hung
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Chiu, Yi
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Shieh, Han-Ping D.
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電控工程研究所
;
光電工程學系
Based on a finite-conjugate objective lens with numerical aperture of 0.62 for a 650-nm wavelength, an optical pickup head composed of a multifunction beamsplitter and a diffractive optical element is designed be used in a swing-arm-type optical pickup head. The diffractive optical element is a lens with an elliptical four-level phase profile to provide both focusing and astigmatism. It is also designed with the goal to simplify the overall optical configuration and provide linear characteristics for the focus error signal. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI:10.1117/1.3158944]
Binary-phase micrograting and polarization beamsplitter for free-space micro-optical pickups
(2007-08-01)
Lee, Chi-Hung
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Chiu, Yi
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Shieh, Han-Ping D.
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電控工程研究所
;
光電工程學系
A pop-up binary-phase micrograting and a pop-up micro polarization beamsplitter, for potential use in micro-optical pickups, have been realized on a single silicon chip using a two-layer polysilicon and one-layer silicon nitride micromachining process. In the case of the micrograting, a diffraction efficiency ratio between 4 and 10 can be achieved provided that the duty cycle is between 0.4 and 0.6 and the depth between 455 and 485 nm, respectively. For a grating designed for a diffraction ratio of 7, the measured ratio is 8.31. The polarization beamsplitter is a silicon nitride thin film placed at the Brewster angle. The transmittance of the TM mode was measured to be more than 98.5%, while the reflectance of the TE mode was 21.4%. (c) 2007 Society of Photo-Optical Instrumentation Engineers.
Characterization of a burn-in failure caused by a defective source driver on TFT-LCD panel
(2006)
Wang, Fred S. C.
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Lin, Keh-La
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Tso, Ko-Yang
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Chao, Chin-Chieh
;
Wang, Wai William
This paper describes a thorough investigation to identify the root cause of an LCD panel bum-in failure induced by an LCD source driver, which is observed in a large-scale LCD factory producing more than one million LCD panels per month. The investigation demonstrates the effectiveness of the circuit simulation to precisely locate the defective spot which is caused by a metal slice originated from outer rings of an LCD COG (chip-on-glass) source driver. With the aid of emission microscope (EMMI), Energy Dispersive Analysis X-Ray (EDAX), and Chip Probing (CP) tester, the root cause of the failure is well explained. The formation mechanism of metal slice from the outer rings is thoroughly studied. A solution to completely eliminate the source of metal slices from the outer rings during wafer processing is also proposed.
CMOS-MEMS accelerometer with differential LC-tank oscillators
(2012)
Chiu, Yi
;
Hong, Hao-Chiao
;
Wu, Po-Chih
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電機資訊學士班
;
Undergraduate Honors Program of Electrical Engineering and Computer Science
This paper presents a CMOS-MEMS accelerometer based on differential LC-tank oscillators. Two LC-tank oscillators composed of differential MEMS capacitors and suspended inductors were designed and fabricated by standard TSMC 0.18 mu m CMOS processes and post-CMOS dry etching. The outputs of the differential oscillators are mixed and the output frequency of the mixer is proportional to the capacitance change caused by external acceleration. The device has been characterized and has a mechanical resonance frequency of 3.3 kHz, sensitivity of 3.7 MHz/g, and nonlinearity of 1.8%.
Design and fabrication of a micro electrostatic vibration-toelectricity energy converter
(2006)
Chiu, Yi
;
Kuo, Chiung-Ting
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Chu, Yu-Shan
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電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a micro electrostatic vibration-to-electricity energy converter. For the 3.3 V supply voltage and 1 cm(2) chip area constraints, optimal design parameters were found from theoretical calculation and Simulink simulation. In the current design, the output power is 200 mu W/cm(2) for the optimal load of 8 M Omega. The device was fabricated in a silicon-on-insulator (SOI) wafer. Mechanical and electrical measurements were conducted. Residual particles caused shortage of the variable capacitor and the output power could not be measured. Device design and fabrication processes are being refined.
Design and Fabrication of a Small-Form-Factor Optical Pickup Head
(2009-05-01)
Chiu, Yi
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Shih, Hsi-Fu
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Chiou, Jin-Chern
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Cheng, Shih-Tung
;
Hung, Kuo-Yung
This paper presents the design and fabrication of a small-form-factor optical pickup head (OPH) for both red and blue wavelength. A holographic optical element (HOE) is used for beam splitting, aberration correction, and servo-signal generation to reduce the number of components and simplify the assembly procedure. In addition to demonstrating this OPH by using existing discrete components, several key components and processes are developed to use micro-electro-mechanical system (MEMS) technology to facilitate batch fabrication and wafer level assembly of the micro OPU.
Design and Fabrication of Micro Hot-wire Flow Sensor Using 0.35 mu m CMOS MEMS Technology
(2014-01-01)
Miao, Zhuonan
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Chao, Christopher Y. H.
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Chiu, Yi
;
Lin, Chia-Wei
;
Lee, Yi-Kuen
MEMS sensors are promising for Energy Efficient Building (EeB) because of the potential low cost and low power consumption. Various flow sensors based on MEMS technology have been fabricated. In this work, we designed and fabricated a polysilicon micro hot-wire flow sensor using a commercial 0.35 mu m 2P4M CMOS technology followed by post-CMOS processing. A post-CMOS MEMS process for a 1.5mmx1.5mm sensor chip using Deep Reactive Ion Etch (DRIE) and spray coating was utilized to finish the fabrication. The fabricated flow sensor was characterized at different flow rates. The fabricated sensor with a dimension of 300 mu mx2 mu mx3.76 mu m demonstrated a sensitivity of 23.87 mV/(m/s) and power consumption of 0.79 mW at U-in= 5m/s. The experiment results were consistent with the theoretical prediction and the best results showed an average error of only 5%.
Design of a 0.20-0.25-V, Sub-nW, Rail-to-Rail, 10-bit SAR ADC for Self-Sustainable IoT Applications
(2019-05-01)
Hong, Hao-Chiao
;
Lin, Long-Yi
;
Chiu, Yi
;
電機工程學系
;
Department of Electrical and Computer Engineering
This paper presents a 10-bit SAR ADC operating at a supply voltage (VDD) from 0.200 to 0.250 V. In the proposed ADC structure, the positive input of the comparator is fixed at VDD to bias the comparator's input transistor pair with a sufficient gate-to-source voltage at such a low VDD. We propose an ultra-low VDD temperature-compensated bias generator to bias the comparator for addressing the severe temperature-dependent issue of the MOSFETs in the comparator, which operate in the deep subthreshold region. Detailed circuit analysis and derivation of design requirements are presented. A double-boosted and low-leakage sampling switch is also proposed to alleviate the severe leakage issue at low sampling rates. A test chip has been designed and fabricated in 180-nm CMOS. The ADC core occupies only 0.024 mm(2). Measurement results show that the ADC achieves stable performance in the VDD range. At 0.225 V, the DNL and INL are within +1.04/-0.66 and +0.97/-1.04 LSB in the rail-to-rail input range, respectively. The measured peak SNDR at the Nyquist input frequency is 49.2 dB at 450 S/s. The whole ADC totally consumes 0.85 nW at 0.225 V including circuit leakages. The sub-nW power consumption makes it well suited for self-sustainable Internet-of-Things applications.
Design, fabrication, and control of components in MEMS-based optical pickups
(2007-02-01)
Chiu, Yi
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Chiou, Jin-Chern
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Fang, Weileun
;
Lin, Yung-Jiun
;
Wu, Mingching
Small-form-factor optical pickups and disk drives have been an area of intense research since the rise of portable consumer electronic products. In current technology, most of the devices are manufactured by the precision assembly of discrete miniaturized optomechanical components. The assembly process can be simplified and cost reduced by using the batch fabrication processes developed in microelectro-mechanical systems (MEMS). In this paper, the fabrication and testing of optical and actuator components for a MEMS-based optical pickup are presented. A novel design methodology is also applied to the servo control system of the pickup.