Browsing by Author "Chou, BCS"

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A photonic device compatible process in fabricating tunable Fabry-Perot filter
(2002-09-15)
Lin, WT
;
Chiou, JC
;
Chou, BCS
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A photonic device compatible low temperature process that is suitable for fabricating tunable Fabry-Perot filter is proposed in this paper [1]. The advantages of the presented process consist of (1) materials used in this process are compatible with existing optical or IC process; (2) process and detected spectra are not limited by different substrates. Experimental results of the manufactured tunable Fabry-Perot filter indicated that the full-width-half-maximum (FWHM) is closed to 1.3 nm and the measurement of reflectance of distributed Bragg reflectors is up to 99%. Note that within the 10 nm experimental tuning range, the FWHM is kept close to 1.3 nm with tuning voltage from 0 to 30 V. The experimental results showed that the presented process has potential to apply to wavelength division multiplexing (WDM) specifications of optical telecommunication. In particular, the process would also be integrated to fabricate tunable VCSEL processes. (C) 2002 Elsevier Science B.V. All rights reserved.
A sensitive Pirani vacuum sensor and the electrothermal SPICE modelling
(1996-05-01)
Chou, BCS
;
Chen, YM
;
OuYang, M
;
Shie, JS
;
交大名義發表
A sensitive micro-Pirani vacuum sensor has been fabricated. With effective schemes of ambient-temperature compensation and stabilization, it is capable of measuring vacuum pressure linearly from 1 torr down to 10(-7) torr, a three orders-of-magnitude improvement in resolution over conventional gauges. A special electrothermal SPICE model, complementary to the conventional analog representation of thermal parameters, is also proposed. It allows a high-level sensor-circuit integrated simulation based on the most fundamental principle and thermal variables. Good agreement between the measured data obtained from a constant-temperature readout circuit and the simulation result is demonstrated.
An innovative Pirani pressure sensor
(1997)
Chou, BCS
;
Shie, JS
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
A conventional Pirani vacuum sensor is converted into a device able to measure high gas pressure. By referring to infinite pressure, heat-loss change from the reference to a measured pressure induces electrical signal on the resistive sensor. 0.3 mu m shallow gap is formed for the floating microsensors to increase its sensitivity. This results ire a measurable range from 10(5) down to 10(-1) Torr. The thermal microsensor differs from the piezoresistive or capacitive type in sensing mechanisms. It also has advantages in smaller size and simpler structure.
Characterization and modeling of metal-film microbolometer
(1996-12-01)
Shie, JS
;
Chen, YM
;
Mang, OY
;
Chou, BCS
;
光電工程研究所
The characteristic thermal parameters of a platinum-film microbolometer are extracted from the data of two measuring methods, A simple and accurate equivalent circuit model, along with its thermal behavior, is proposed for the device. Applying the model to simulate some device circuits results in good agreement with the experimental data, Furthermore, an effective method of ambient temperature compensation, proposed previously by our laboratory, is demonstrated both experimentally and by simulation using the same model. The established electro-thermal model therefore serves as an useful tool for SPICE simulations in the design of microbolometers.
Characterization and modeling of metal-film microbolometer
(1996-12-01)
Shie, JS
;
Chen, YM
;
Mang, OY
;
Chou, BCS
;
交大名義發表
The characteristic thermal parameters of a platinum-film microbolometer are extracted from the data of two measuring methods, A simple and accurate equivalent circuit model, along with its thermal behavior, is proposed for the device. Applying the model to simulate some device circuits results in good agreement with the experimental data, Furthermore, an effective method of ambient temperature compensation, proposed previously by our laboratory, is demonstrated both experimentally and by simulation using the same model. The established electro-thermal model therefore serves as an useful tool for SPICE simulations in the design of microbolometers.
Current-temperature characteristics of low-temperature-sputtered (Ba,Sr)TiO3 films post treated by rapid thermal annealing
(2002)
Shye, DC
;
Chen, JS
;
Kuo, MW
;
Chou, BCS
;
Jan, CK
This work reports the current-temperature characteristics of the low-temperature-sputtered (Ba0.8Sr0.2)TiO3 (BST) film post treated by rapid thermal annealing (RTA) in O-2 ambient. The top electrode was biased under negative/positive voltage to investigate the interface properties of the Pt/BST/Pt multifilm. As the results, the current density of the RTA-treated BST film was greatly reduced owing to compensation of oxygen vacancies. The RTA-treated BST thin film biased at negative voltage exhibits a negative temperature-coefficient-resistivity (NTCR) behavior, but, intriguingly, that biased at positive voltage reveals a positive temperature-coefficient-resistivity (PTCR) behavior. According to the leakage current analysis, the Schottky emission dominates the negative biased current at upper interface, but the Heywang barrier scattering confines the positive biased current.
Dependence of polarization on temperature coefficient resistance of (Ba, Sr)TiO3 thin films post-treated by RTA
(2003-04-01)
Shye, DC
;
Chiou, BS
;
Kuo, MW
;
Chen, JS
;
Chou, BCS
The temperature coefficient of resistance (TCR) characteristics of Pt/(Ba0.8Sr0.2)TiO3 (BST)/Pt thin-film resistors are studied for the BST films with rapid thermal annealing (RTA) treatments. The polarizations induced by bias voltages greatly influence the TCR characteristics. The RTA-treated BST thin film exhibits negative TCR (NTCR) behavior at a negative voltage, but, intriguingly, positive TCR (PTCR) behavior at a positive voltage. According to the leakage current analysis, Schottky emission dominates the negatively biased current at the upper interface, but Heywang barrier scattering confines the positive biased current. (C) 2003 The Electrochemical Society.
Fabrication and study of a shallow-gap Pirani vacuum sensor with a linearly measurable atmospheric pressure range
(1999-01-01)
Chou, BCS
;
Chen, CN
;
Shie, JS
;
光電工程研究所
;
Institute of EO Enginerring
A Pirani vacuum sensor with a shallow gap between its heated element and its surrounding substrate heat-sink was fabricated using polysilicon as a sacrificial layer. The polysilicon was post-etched by TMAH solution, and an anti-stiction method was used in several steps of the process including a crucial freeze-drying one. The smallest spacing in this device is 0.3 mu m, and via this narrow gap, the heat conductance from the gas-molecule-collisions from the hot element to the heat sink is greatly enhanced in the atmospheric pressure regime. Therefore, this Pirani vacuum sensor is capable of detecting gas pressure linearly up to around 7 bars. As for the low-pressure regime, a partial dummy compensation method reduces the ambient temperature drift effectively and pressure lower than 10(-3) Torr was measurable. Moreover, device packaging was also studied to protect the tiny sensor from any contamination including dust and particles.
Fabrication and study of a shallow-gap Pirani vacuum sensor with a linearly measurable atmospheric pressure range
(1999-01-01)
Chou, BCS
;
Chen, CN
;
Shie, JS
;
光電工程學系
;
Department of Photonics
A Pirani vacuum sensor with a shallow gap between its heated element and its surrounding substrate heat-sink was fabricated using polysilicon as a sacrificial layer. The polysilicon was post-etched by TMAH solution, and an anti-stiction method was used in several steps of the process including a crucial freeze-drying one. The smallest spacing in this device is 0.3 mu m, and via this narrow gap, the heat conductance from the gas-molecule-collisions from the hot element to the heat sink is greatly enhanced in the atmospheric pressure regime. Therefore, this Pirani vacuum sensor is capable of detecting gas pressure linearly up to around 7 bars. As for the low-pressure regime, a partial dummy compensation method reduces the ambient temperature drift effectively and pressure lower than 10(-3) Torr was measurable. Moreover, device packaging was also studied to protect the tiny sensor from any contamination including dust and particles.
Fabrication of low-stress dielectric thin-film for microsensor applications
(1997-12-01)
Chou, BCS
;
Shie, JS
;
Chen, CN
;
光電工程研究所
;
Institute of EO Enginerring
A method of fabricating low-stress dielectric thin film as the supporting material of micromachined devices is reported. The film is processed by post thermal oxidation of silicon-rich nitride (SN) deposited on silicon substrate by LPCVD. Due to the compensation on the nitride by its top oxide, an ultra-low residual less than 10 MPa can be obtained with proper oxidation scheme. Characteristics of the oxidized nitride were analyzed by Auger electron spectroscopy (AES) and ellipsometry. Large floating membranes of 4 x 4 cm(2) and 400-nm thick can be made by this method with TMAH etching.
Fabrication of low-stress dielectric thin-film for microsensor applications
(1997-12-01)
Chou, BCS
;
Shie, JS
;
Chen, CN
;
交大名義發表
;
光電工程學系
A method of fabricating low-stress dielectric thin film as the supporting material of micromachined devices is reported. The film is processed by post thermal oxidation of silicon-rich nitride (SN) deposited on silicon substrate by LPCVD. Due to the compensation on the nitride by its top oxide, an ultra-low residual less than 10 MPa can be obtained with proper oxidation scheme. Characteristics of the oxidized nitride were analyzed by Auger electron spectroscopy (AES) and ellipsometry. Large floating membranes of 4 x 4 cm(2) and 400-nm thick can be made by this method with TMAH etching.
Micromachining on (111)-oriented silicon
(1999-06-08)
Chou, BCS
;
Chen, CN
;
Shie, JS
;
光電工程學系
;
Department of Photonics
Micromachining on (111)-oriented silicon in various alkaline solutions was studied. By means of spoke and donut-like etching patterns, the experiment shows that [110] directions have the highest etch rate and the final emergent periphery is hexagon bounded on the bottom surface plane. The six sidewalls are defined by {111} planes, which can be derived from its crystal geometry, having three facets with inclining angles of 70.5 degrees and another three with declining angles of 109.5 degrees respect to the (111) surface plane. SEM pictures show that aqueous KOH solution results in smooth surface morphology due to its higher etch rate of residual oxide existed in the silicon, while the other etchants such as hydrazine (N2H4) and tetramethyl ammonium hydroxide (TMAH) induce seriously wavy roughness. Moreover, various concentrations of KOH solution have been studied to determine the (110)/(111) etch ratio, and the ratio more than 100 were demonstrated. Using this method, suspended single-crystal silicon (c-Si) microstructures were fabricated for some potential uses such as thermopile, silicon bolometer, mass flow transducer and other force microsensors. As an application example, shallow-gap mu-Pirani vacuum sensor demonstrated its high pressure measuring capability as high as 10(3) Torr. (C) 1999 Elsevier Science S.A. All rights reserved.
Parameters study to improve sidewall roughness in Advanced Silicon Etch process
(2001)
Liu, HC
;
Lin, YH
;
Chou, BCS
;
Hsu, YY
;
Hsu, WS
In ICP-RIE process, there have been many investigations on etching rate. However, only few published reports mentioned the sidewall roughness, which is a critical issue for optical devices. Here, experimental investigations about fabrication parameters in the STS Advanced Silicon Etch (ASE) process for sidewall roughness are performed. In our experiments, the photoresist of AZ1500 is used, and several parameters in the ASE process like over time, ramping time, Ar flow rate, platen power, and etching cycle time have been systematically studied. It is found that sidewall mean roughness can be down to 9.11 nm at etching rate of 2.5 mum/min. Comparing with other published works at similar sidewall roughness (around 10 nm), our experimental data have the highest etching rate. For the same STS ICP-RIE systems, our data have smallest sidewall roughness, comparing to previous literatures.