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A new CMOS readout integrated circuit (ROIC) for microbolometric focal plane array (FPA) is proposed in this paper. By applying multiple-module parallel working technique, the pixel readout speed of the CMOS ROIC can reach 10 MHz, which is very suitable for large-scale microbolometer array. The CMOS ROIC of each parallel working module consists of three major parts: direct injection (DI) input circuits, column-shared integrating circuits, and common noise-suppressing circuits. The readout structure of the ROIC is simple because of the DI input, shared and common circuits, and this makes the ROIC satisfy the requirements of small-pixel microbolometric FPA. Furthermore, the voltage signals from different working modules can be output according to a certain order through a high-speed output circuit. An experimental readout chip based on the proposed ROIC has been designed and fabricated to verify its readout function and performance. The measurement results of the experimental readout chip have successfully proved that the proposed CMOS ROIC can be applied to high-speed, low-noise, large-scale and high-resolution microbolometric FPA.

The physical thermal model for micro-bolometer under pulsed voltage bias is built, and the current responsivity expression of the micro-bolometer based on this physical thermal model is approximatively obtained in theory, which is in accordance with the numerical calculation of micro-bolometer current responsivity. Theoretical analysis shows that the current responsivity parameter is changed with voltage bias time, and this indicates that the current responsivity of micro-bolometer under pulsed voltage bias can be controlled by adjusting useful voltage bias time which is equal to micro-bolometer current integration time. The expression of the current responsivity parameter reveals key factors relevant to the output signal signal-to-noise of micro-bolometric focal plane array, and theoretically gives one of the directions to increase the output signal signal-to-noise of micro-bolometric focal plane array.

An operation model of a negative microlens array is demonstrated. The array consists of two kinds of materials with different refractive indices. First of all, a positive microlens array with 256×256 elements serving as a pattern is fabricated by argon ion beam etching on the quartz. The diameter and average corona height of the element are 28 and 0.638 μm, respectively. The spacing between two neighboring elements is 2 μm. In the second phase, after being coated by epoxy, the positive microlens array pattern is spun and baked, leading to a complex negative microlens array. Surface stylus measurement shows that the surface of the positive quartz microlens array is smooth and uniform. Focal length measurement of the negative microlens array indicates that the focal length region with −731±3 μm is in good agreement with the theoretical calculation value of −729 μm.

Vanadium oxide films have been fabricated on Si 3 N 4 -film-coated silicon substrates by direct current reactive magnetron sputtering method. Conditions of deposition are optimized making use of parameters such as sputtering time, dc power, oxygen partial pressure and substrate temperature. X-ray diffraction indicates that the film is a mixture of VO 2 , V 2 O 3 , and V 3 O 5 . Four-probe measurement shows that the VO x thin film owns high temperature coefficient of resistance (TCR ∼−2.05%/°C) and suitable square resistance 18.40 kΩ/□ (measured at 25 °C), indicating it is a well candidate material for uncooled IR detectors. In addition, IR absorption in the wavelength of 2–16 μm has been characterized. It is worth noting that the films are sputtered at a relatively low temperature of 210 °C in a controlled Ar/O 2 atmosphere. Compared to traditional craft, this method needs no post-anneal at high temperature (400–500 °C).

In this paper, 32 × 32 infrared (IR) uncooled focal plane arrays (UFPAs) based on nanostructured vanadium oxide (VOx) thermally sensitive material are fabricated by micromachining processes. The thermally sensitive element is fabricated on the complementary metal–oxide–semiconductor (CMOS) chip after planarization of its surface. In this paper, silicon dioxide is used as a buffer layer for fabrication of nanostructured VOx. The interconnection of the CMOS chip and the sensitive array is accomplished by electroless plating of nickel (Ni) metal, which shows good electrical conductivity performance. The IR sensitive testing results illustrate that the response of the microbolometer is obvious and the average responsivity and normalized detectivity are 1.26 × 104 V W−1 and 2.04 × 107 cm W−1 Hz1/2, respectively.

This paper presents a new low temperature silicon-glass anodic bonding process using induction heating. Anodic bonding between silicon and glass (Pyrex 7740) has been achieved at temperature below 300 °C and almost bubble-free interfaces have been obtained. A 1KW 400KHz power supply is used to induce heat in graphite susceptors (simultaneously as the high-voltage electrodes of anodic bonding), which conduct heat to the bonding pair and permanently join the pair in 5 minutes. The results of pull tests indicate a bonding strength of above 5.0MPa for induction heating, which is greater than the strength for resistive heating at the same temperature. The fracture mainly occurs across the interface or inside the glass other than in the interface when the bonding temperature is over 200 °C Finally, the interfaces are examined and analyzed by scanning electron microscopy (SEM) and the bonding mechanisms are discussed.

Vanadium oxide films with temperature coefficient of resistant of −2.6% K−1 have been fabricated on Si3N4-film-coated Si substrates by ion beam sputtering in a controlled Ar/O2 atmosphere, at a relatively low growth temperature of 200 °C. The as-deposited films show no semiconductor-to-metal phase transitions even heated up to 150 °C. X-ray diffractometry shows that the main compound of the VOx film is a metastable phase of vanadium dioxide (VO2(B)) and the VO2(B) film can be transformed into VO2 film by post-growth annealing at 450 °C in flowing Ar atmosphere.

This paper presents a planarization procedure to achieve a flat CMOS surface of Readout Integrated Circuit (ROIC) for the integration between uncooled infrared detector arrays and ROIC. The CMOS fabrication process produces about 2 μm surface roughness on the silicon wafer, so the CMOS dies must be first planarized before integration with the detector arrays. To acquire a satisfying surface roughness in the small CMOS die, three commercially available polymers including bisbenzocyclobutene (BCB) and two types of polyimides are evaluated in our experiments. BCB shows the best results for our applications. A single layer of BCB coating successfully reduce the surface topology from 2 μm to less than 1500 A and two layers of BCB coating reduce the surface topology to about 600 A.

Vanadium dioxide films for optical switching applications have been prepared on Si 3 N 4 -film-coated silica substrates by ion beam sputtering from a vanadium metal target in an atmosphere of argon and oxygen and subsequent heat treatment. The as-fabricated VO 2 films exhibit a nanocrystalline structure and undergo abrupt changes in electrical and optical properties with an abnormal low transition temperature of 34 °C. Using micromachining technology, applications of the films as thermo-optical switches are also demonstrated. The measured average optical isolation for the switches is 15 dB with a −2 dB insertion loss at a wavelength of 1.55 μm.

This paper presents an optical switch based on a vanadium dioxide VO 2 thin film fabricated on quartz and Si substrates. Vanadium oxide thin films with 48 °C semiconducting-to-metal phase transition temperature are fabricated by reactive ion beam sputtering followed by a post-annealing process step. Optical tests at λ = 1.55 μm show that the insertion loss and contrast ratio of fabricated switches are 2 dB and more than 15 dB, respectively. Switching times under 1 ms have also been observed and the power consumption of an individual switch is less than 25 mW.

In this paper, the integration of an experimental 32 × 32 uncooled IR microbolometer array with an unplanar CMOS Readout Integrated Circuit (ROIC) is presented. A vanadium oxide film fabricated by low temperature reactive ion beam sputtering is utilized as thermal-sensitive material in the bolometric detectors Before the integration, the unplanar ROIC for commercial use is first planarized by bisbenzocyclobutene film, then a electroless nickel-plating on ohmic contact areas is accomplished. Finally the bolometer array is fabricated using a micromachining process, which is completely compatible with CMOS technology. Measurements and calculations for the as-fabricated samples show that the responsivity of 1.4 × 104 V/W and the detectivity of 2.1 × 108cmHz1/2W−1 and a thermal response time of 10ms are obtained at a pulse bias of IV.

In this paper, we develop an integration technology between Si microlens and 256(H)×256(V) element PtSi Schottky-barrier infrared charge coupled device (IR-CCD) to improve the optical responsivity of CCD sensor. The refractive microlenses with the pixel size of approximately 28×28 μm 2 is directly fabricated on the backside of CCD substrate to focus the incident irradiation onto the active area. For the integration device the fill factor is improved by a factor of 2.1. As a result, the IR-CCD image sensors operating at 77 K indicate an approximate 0.06–0.4 increase in relative optical responsivity in the spectral range of from 1 to 5 μm . CCD imaging quality with microlens has been improved comparing to that without microlens to a great extent.

In this paper, reliability of anodically bonded packages between silicon and borosilicate glass wafers has been investigated. The effects of certain accelerated environmental tests such as thermal cycling; thermal shock and boiling test on bonding quality are evaluated. The bonding strength is measured using an in-house tensile tester and fracture mainly occurs inside the glass wafer other than along the interface, indicating the robustness of the bond. The experiments conducted show that fast cooling after bonding results in high thermal stress in glass, which deteriorated the mechanical performances. Thermal cycling and thermal shock can help relax thermal stress, while boiling does do harm to bonding strength owing to their different effect on microstructures. Finally, the fracture interfaces are examined and analyzed by scanning electron microscopy (SEM).

Vanadium oxides thin films for uncooled bolometric detectors have been fabricated on Si3N4-film-coated Si substrates by low temperature reactive ion beam sputtering in a controlled oxygen atmosphere. The typical growth temperature is kept at 200°C during sputtering, which is compatible with the post-CMOS technology. The as-deposited film exhibits sheet resistance and temperature coefficient resistant of 32 kΩ and −0.025 K−1 at room temperature, respectively.

A conventional microstructure of vanadium dioxide film with grain size of 1–2 μm exhibits a phase transition from a lower-temperature semiconductor phase to a higher-temperature metal one with a phase transition temperature of 68°C and with resistivity changes two to three orders of magnitude. Here, we report a nonconventional nanopolycrystalline thin film structure of vanadium dioxide with an average grain of 8 nm and with a phase transition temperature of about 35°C, indicating more promising device applications such as smart window coatings for solar energy, uncooled infrared imaging technology, optical and electronic switching devices, etc.

Polycrystalline VOx thin films were grown on Si substrates by ion beam sputtering deposition and annealing in oxygen atmosphere, which were prepared for thermal-sensitive material of far infrared (IR) sensors. As the deposition temperature (∼150 °C) is lower compared to that (∼400 °C) used to deposit single phase of VO2, scanning electron microscopy (SEM) morphology indicates that the as-deposited vanadium oxide (VOx) thin films were very smooth in surface and their grains are not able to be resolved. After annealing at higher temperature, the thin films were grown finally into ball-like and skeleton-like grains. The four-probe test presents their sheet resistance and the temperature coefficient of resistance (TCR) of the VOx thin film, which are 50 kΩ/□ and −0.021 K−1 at 30 °C, respectively. In addition, IR absorption in the range of 2–20 μm has been characterized.

Polycrystalline VO 2 thin films were obtained on Si substrates by ion beam sputtering deposition and annealing in flowing Ar gas. SEM images indicate that VO 2 thin films were grown into compact surfaces. Four-probe measurements indicated that the VO 2 thin films own good electrical homogeneity. After the films' production, micromachining technology including lithography, reaction ion etching and metallization connection processes was used to produce the optical switch array. As a result, the 128×128 element optical switch array was achieved.

Microlens array is an important optical element to improve the photosensitivity of charge-coupled device (CCD). In this paper, a monolithic integration technology between microlens and 528 × 528 element PtSi Schottky-barrier infrared charge-coupled device (IRCCD) with a pixel size of 30μm × 30μm has been developed. The microlens array with low sag and long focal length is designed based on geometrical optics theory. It is directly formed on the back side of the substrate in IRCCD chip using successive photolithography and A+ ion beam etching (IBE) technology. The microlens array is characterized by both surface stylus and point spread function (PSF). The experiment results of integration device between IRCCD and microlens array indicate that the optical signal response is improved obviously and a responsivity increase by a factor of 1.8 in the operation band.

Polycrystalline VO x thin films were deposited on Si substrates by ion beam sputtering deposition in oxidation atmosphere. SEM images show that VO x thin films were grown into compact and smooth surfaces. Four-point probe measurements indicated that the VO x thin films own good homogeneity and high temperature coefficient of resistance (TCR ∼ −0.02 K −1 ). After the films’ deposition, micromachining processes including lithography and metallization connection was used to fabricate the detector array. As a result, the 128 element of IR detector array with a responsivity of 2 × 10 8 cm Hz 1/2 /W and a detectivity of 5 kV/W at current bias of 100 μA were achieved.

Quantum size effect in antimony thin films has been investigated. The Sb(1 1 1) thin films were grown on GaAs (0 0 1) substrates by molecular-beam epitaxy (MBE) at growth temperatures between 25 and 150 °C and with Sb film thicknesses between 5 and 200 nm. The film structures were analyzed by both reflection high-energy electron diffraction (RHEED) and transmission electron microscopy (TEM). The energy gap versus thickness for Sb films was tested. A semimetal-to-semiconductor transition in Sb films grown on GaAs substrates has been demonstrated. Narrow energy gap materials with tailorable gaps are of great interest as novel infrared detector materials. A design for Sb-GaAs quantum well infrared detector is presented.

This paper presents a method to make vanadium dioxide (VO 2 ) crystallites on silicon substrates by reactive ion beam sputtering. The thickness of the thin film is about 100 nm. The transmittance of the semiconducting phase VO 2 is about 54% and it is reduced to as low as 3% in metal phase at the wavelength of 10.6 μm. And the ratio of the transmittance of these two states is measured being 18:1. When a destructive light intensity is above 0.85 W/cm 2 at 10.6 μm, most of the light could be reflected by the thin film, thus the sensitive infrared detector is protected from strong laser radiation.

In this letter, novel optical switches based on VO2 thin film on substrates of silicon (1 0 0) has been fabricated. The vanadium dioxide thin films were deposited by reactive ion beam sputtering followed by a post-annealing. Testing shows the insertion loss of the optical switches is 1–2 dB, and the extinction ratio up to 26 dB. The speed of the switches is as fast as 3 ms.

To improve the performance of infrared focal plane arrays, multi-phase-level 256 × 256 element diffractive microlens arrays with a center wavelength of 4 µm are designed using a novel partial etching method based on the scalar diffraction theory and computer aided design. A testing system is established with an optical communication semiconductor laser and detector for measuring the diffraction efficiency and point spread function of the designed multi-phase diffractive microlens arrays. The measurement results indicate that the measured diffraction efficiency of 16-phase Si and quartz diffractive microlens arrays are 83.7% and 87.5%, respectively, and the optical response of the infrared focal plane arrays with integration of the diffractive microlens arrays is increased by a factor of 2.23.

Polycrystalline VO x thin films that were prepared for thermal-sensitive material of far infrared sensor had been deposited on Si substrates by ion beam sputtering deposition. Scanning electron microscopy images indicated that VO x thin films (oxygen pressure of 1.5×10 −3 Pa) were grown into compact and ultra-fine grains (⩽50 nm), the film surfaces seemed smooth and uniform. Four-point probe measurements showed that the homogeneity of the films was better than 98% in a size of 30×30 mm 2 . The four-point probe measurement on hot plate presented the sheet resistance and the temperature coefficient of resistance of the VO x thin film that were 50 kΩ/square and −0.021 K −1 at 28°C, respectively. In addition, some samples annealed in Ar atmosphere had their resistance decreased. Thus, vanadium oxide films containing more amount VO 2 were obtained.

Polarization-insensitive 1.3 µm InGaAsP–InP multi-quantum-well (MQW) superluminescent diodes (SLDs) were grown by MOVPE. Both compressively-strained wells and tensile-strained wells were employed in the active region. The SLDs were fabricated into ridge waveguide structures with 7° tilted cavity and buried-window end facets. The two facets were coated with four layer anti-reflection TiO2/SiO2 films and residual facet reflectivity was found to be less than 0.02%. The SLDs exhibited up to 16.9 mW optical output power and less than 1 dB polarization dependence of output power with less than 0.2 dB optical spectrum modulation at 200 mA.

A 1.55 µm polarization-insensitive lateral tapered spot-size converter integrated semiconductor optical amplifier (SSC-SOA) with tensile-strained barriers was investigated. The optical amplifier structure used a conventional ridge guide for the active layers and a second larger ridge for the passive waveguide. Low beam divergence of 12° × 15° results in about 3.1 dB coupling losses with −1 dB positional tolerances of ±2.3 µm and ±1.6 µm in horizontal and vertical directions using an anti-reflection coated flat-ended single-mode fibre. The active layer of SSC-SOA consisted of a tensile-strained barrier multiple-quantum-well structure. The SSC-SOA exhibited a signal gain of 25.5 dB and a saturation output power of 11.2 dB m with excellent polarization insensitivity (less than 0.5 dB) at 200 mA.

High power polarization-insensitive InGaAsP-InP multiple quantum well (MQW) superluminescent diodes (SLD's) emitting at 1.3μm were investigated. A combination of tensile strained and compressively strained quantum wells called complex strained MQW were used in a single active layer in order to obtain polarization insensitivity. Low-pressure metalorganic chemical vapor phase epitaxy was used for crystal growth. High resolution X-ray diffraction and photoluminescence spectra showed excellent crystal quality. The SLD's were fabricated to ridge waveguide structure with 7° tilted cavity, the two facets were coated with two layers anti-reflection TiO2/SiO2 films, residual facet reflectivity was found to be less than 0.04%. The SLD's exhibited a up to 18.8 mW optical output power and less than 1 dB polarization dependence of output power with a less than 0.5 dB optical spectra modulation at 250 mA.

Infrared charge coupled device (IRCCD) integration with microlens array is an effective method for improving the detecting sensitivity of IRCCD sensors. In this paper, we present the diffractive microlens array (MLA), which is manufactured by the submicron photolithography technology and magnetically enhanced reactive ion etching (MERIE) on infrared quartz substrate. The integration procedure between microlens array and PtSi Schottky-barrier IRCCD chip is introduced in detail. The optical response of IRCCD sensor with microlens array is tested and the average response increases 0.23 in the spectral range of 1.2∼5.0 μm. The measuring results show that the large-scale diffractive microlens array is able to improve the detecting sensitivity of IRCCD and that the integration technology mentioned is available.

A polarization insensitive AlGaInAs–InP semiconductor optical amplifier was realized at a wavelength of 1310 nm. The active layer consisted of three tensile strained wells with a strain of 0.35%. The amplifiers were fabricated into a ridge waveguide structure, which showed excellent polarization insensitivity (less than 0.3 dB) at 1310 nm with a gain of 22.5 dB at 200 mA. the AlGaInAs–InP optical amplifier shows good temperature characteristics, less than 3 dB reduction in the gain when the temperature is raised from 25 to 65 °C, the polarization sensitivity remains less than 0.8 dB over the entire range of wavelength.

This paper presents a method to make vanadium dioxide (VO2) crystallites on silicon substrates by reactive ion beam sputtering. The thickness of the thin film is about 100nm. The phase transition temperature of VO2 is 65°C. The transmittance of the semiconducting phase VO2 is about 50% and it is reduced to as low as 3% in metal phase at the infrared wavelenghth spectrum. The extinction ratio of the optical switches is 12dB. and the insertion loss is of 1-2dB. The switching time is about 1ms.

Microbolometers with 128-linear array utilizing VOx thin films as thermal sensitive material were fabricated using micromachining technology. In order to obtain thermosensitive material with high quality and low cost, a new deposition method of VOx thin film was described in this paper. The process of the new method was compatible with Si micromachining and CMOS technology, which was very important for monolithic integration with CMOS readout circuit. The responsivity and the detectivity of microbolometers were tested to be about 5 kV/W and 2 × 108 cm Hz1/2 W−1 at current bias of 100 μA, respectively.

An operating distance equation of infrared search system with full orientation has been derived for a system design with an infrared point target and with the regular atmosphere condition and objective radiation properties. The traditional operating distance equation of infrared search system is corrected. An equivalent test method of system-operating distance equation is brought forward, if the test conditions are deviated from the regular atmosphere condition and objective radiation properties for the system design. The equation and method can be used to design and test system, and to evaluate comprehensive performances for the infrared search system.

In this letter, a novel optical switch based on vanadium dioxide (VO2) thin film on substrates of silicon (100) has been fabricated. The vanadium dioxide thin films were deposited by reactive ion beam sputtering followed by a post-annealing. The testing result shows the insertion loss of the optical switches is about 1–2 dB, and the extinction ratio is up to 26 dB. The speed of the switches is as fast as 60 ns.

Optical concentration using a microlens with high diffractive efficiency is an important method to improve the fill factor and performances of visible charge-coupled device (CCD) sensors. In this paper, a 516 × 516 element diffractive microlens array (MLA) on the quartz substrate is designed based on scalar diffraction theory and fabricated by submicrometer photolithography technology and magnetically enhanced reactive ion etching. The integration procedures between the MLA and CCD chip are presented. The fill factor of the visible CCD with the MLA increases by a factor of 2.4 in comparison with that of CCD without the MLA. The measuring results show that the large-scale diffractive MLA is able to improve the detecting sensitivity of CCD sensors.

We demonstrate a polarization-insensitive multiple-quantum-well optical amplifer for 1.3 μm wavelength in AlGaInAs-InP material system, using three tensile strained wells with strain of 0.36% in the active region. The amplifiers were fabricated forming ridge waveguide structure, which showed excellent polarization insensitivity (less than 0.6 dB) over the entire range of wavelength (1.28 μm ~ 1.34 μm) and a gain of 22.5 dB at the bias current of 200 mA and 1304 nm wavelength.

The commercial test equipments from Pulse Instruments, Lumitron and Electro Optical Industries Inc. are very expensive. So, we proposed a new method of very low cost test system for testing the non-uniformity and signal/noise (S/N) and other characteristics of the uncooled focal plane array (UFPA). It uses complex programmable logic device to generate the necessary pulse for the UFPA and the low noise low dropout micropower regulator to obtain the low noise bias. A proportional-integral-differential controlled thermal electrical cooler based on micro-processor unit stabilizes the UFPA. The National Instruments 6111E Data Acquisition Card is used to convert the analog output of UFPA into digital signal into computer. Its 12-bits conversion capability provides sufficient accuracy for evaluating the S/N ratio and non-uniformity of 128×128 pixels UFPA. Labview is used to analyze the signal. The instrument is fast and convenient to adapt the system to other types of UFPA. Further discussion is presented to determine factors that affect the accuracy of the tester.

Polarization-insensitive AlGaInAs'InP semiconductor optical amplifier is realized at wavelength of 1.55 μ. The active layer consists of three tensile strained wells with strain of 0.40%. The amplifier is fabricated to ridge waveguide structure. The testing result shows the amplifiers have excellent polarization insensitivity (less than 0.8dB). The 1540 nm wavelength optical gain is 20 dB at the bias current of 200 mA.

Smart window coating is fabricated by using vanadium dioxide (VO2) thin film. The VO2 thin film is nanocrystal structured and has low phase transition temperature which is about 35 °C. This kind of thin film is infrared-optically transparent in the semiconductor phase at low temperatures and highly reflective in the metallic phase at high temperatures. Based on the VO2 thin film, a multilayered structure for smart window is designed and fabricated. The multilayered structure is optically transparent for visible light whether at low temperatures or high temperatures, and is transparent at low temperatures and opaque at high temperatures for infrared light, which is smart for adjusting infrared transmittance. This type of multilayered structure is potential to be applied to green smart windows to realize energy saving function.

Based on scalar diffraction theory, 8-phase-level 256×290 element diffractive microlens arrays with lenslet dimension of 50×33 μm 2 have been fabricated on the back side of PtSi infrared focal plane arrays. The design and fabrication process are discussed. The measurement results indicate that the imaging quality has been greatly improved and the ratio of the signal-to-noise of the infrared focal plane array integration with microlens array is increased by a factor of 2.5.

Monolithic integration method has been demonstrated to increase the fill factor of the infrared focal plane arrays (IRFPA). Which is consists of 256×256 Pt-Si schottky barrier charge coupled devices(CCD) operation in 3-5μm IR region. The relative silicon 256×256 element diffractive microlens arrays have been fabricated on the back side of the substrate of the IRFPA using binary optics technology. The aligning process between IRFPA and microlens arrays on each side of the substrate has been completed by IR mask aligner. The testing results show that the imaging quality is very good and the average optical response of the IR FPA is increased by a factor of 3.0, which is improved by about 25% compared with the hybrid integration method in the previous work.

V02-based thin film materials on silicon substrates are fabricated by ion beam sputtering and a post-annealing which is different from the conventional fabricating method. An infrared linear microbolometer array with 128 pixels is prepared using as-deposited vanadium dioxide thin films. Optical and electrical properties for V02-based microbolometer array are tested.

This paper describes the deposition of poly-crystal mixed vanadium oxide thin films on substrates of quartz glass and Si(1 0 0) by reactive ion-beam sputtering followed by post-deposition annealing, and the fabrication of experimental linear uncooled microbolometer array infrared detectors on the quartz substrate as well. SEM and XRD indicate that the films have a smooth compact surface morphology with needle like grains and poly-crystal structure of mixed vanadium oxides. The characteristics of the detectors are investigated to infrared radiation in the spectral region of 8–12 μm at an operation temperature of 296 K. At a chopping frequency of 30 Hz, the fabricated detectors exhibit D* of 1.89×10 8 cm Hz 1/2 W −1 , NEP of 1.67×10 −11 W Hz −1/2 and τ of 11 ms.

Mixed vanadium oxide thin films, as VO2 for the main composition are materials for uncooled microbolometer due to their high temperature coefficient of resistance (TCR) at room temperature. This paper describes the design and fabrication of 8-element linear array IR uncooled microbolometers using the films and micromachining technology. The characteristics of the array is investigated in the spectral region of 8–12 μm. The fabricated detectors exhibit responsivity of up to 10 KV/W, typical detectivity of 1.89×108 cmHz1/2/W, and thermal time constant of 11 ms, at 296 K and at a frequency of 30 Hz. Furthermore, The uncorrected response uniformity of the linear array bolometers is less than 20%.

This report presents a surface pre-treatment method of LPE HgCdTe epilayer to reduce and remove the oxides and contaminants. The surface oxidative characterization of LPE HgCdTe epilayer has been studied by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). HgCdTe surface exposed by various processing steps has been measured and analyzed, the results show the native oxide film can be removed by the solution of lactic acid in ethylene glycol after etching by bromine in absolute ethyl alcohol. It indicates that the mainly optical and electrical parameters of LPE HgCdTe epilayer have not been changed. It is evident that the pre-treatment before HgCdTe surface passivation affects the passivant/HgCdTe interface properties.

Monolithic linear cylindrical microlens array in a quartz glass substrate is fabricated using photolithography and ion beam etching technique, the high-Tc YBa2Cu3O7−δ superconducting thin films are deposited through excimer laser scanning ablation, the superconducting thin films are patterned by photolithographic method and ion beam etching technique, and the hybrid structure of the microlens array component and the superconducting IR detectors has been obtained using an IR glue to cement the microlens component onto the superconducting device. We also investigate the optical response characteristics of the hybrid device in the optical spectral region of 1 ~ 5 μm, as follows. The average optical responsivity \((\overline R )\) of the hybrid device is 1.6×104 V/W, average noise equivalent power \((\overline {NEP} \;)\) is 2.3×10−12 WHz−1/2, average detectvity \((\overline {D^ * } )\) is 3.2×109 cmHz1/2W−1, and the non-uniformity of detectvity (D*) is not more than 14%. The experimental results show that the performance of the superconducting device is improved notably using a quartz glass refractive microlens array as the incident IR radiation concentrators.

α-Sn thin films have been grown on GaAs (001) single crystal substrates by molecular beam epitaxy (MBE). The α-Sn growth process has been characterizedin situ by reflection high energy electron diffraction (RHEED), and the transmission electron microscope (TEM) was used to analyze the interface structures. The measurement results indicate that our metastable a-Sn films have both higher temperature stability which increases by 30°C (from 70 to 100°C) and thickness stability which increases by 200 nm (from 500 to 700 nm) in comparison with previous reports. Other improvements in electrical properties have also been observed. In addition, a new model of multiquantum well structure has been suggested.

Thin films made by vanadium oxide have been obtained by direct current magnetron sputtering method on SiO2 buffer layers. A detailed electrical and structural characterization has been performed on the deposited films by four-point probe method and scanning electron microscopy (SEM). At room temperature, the four-point probe measurement result presents the resistance of the film to be 25 kU/sheet. The temperature coefficient of resistance is − 2.0%/K. SEM image indicates that the vanadium oxide exhibits a submicrostructure with lamella size ranging from 60 nm to 300 nm. A 32 × 32-element test microbolometer was fabricated based on the deposited thin film. The infrared response testing showed that the response was 200 mV. The obtained results allow us to conclude that the vanadium oxide thin films on SiO2 buffer layers is suitable for uncooled focal plane arrays applications.

8-element linear array IR detectors based on high Tc superconducting films have been fabricated. The thin films were deposited by magnetron sputtering onZrO2 substrates and patterned by standard photolithographic technique forming microbridge structure. An average detectivity of 1.85 × 109cmHz1/2 W−1 with a variance of less than 20% in the detector-to-detector detectivity of the array has been obtained at the operating temperature of 84K. A bolometric response mechanism has been discussed.

By using surface micromachining technique, an optical switch based on nanocrystalline VO2 film with low phase transition temperature is designed and fabricated. Measured results show that the optical switch can realize its switching function.

A new self-alignment process to fabricate microlens arrays is introduced. By this method, during the fabrication process, the rigorous alignment is avoided which has great effect on diffraction efficiency in the conventional multi-photolithography process. The large arrays of 1500×640 element silica microlens are manufactured by this method. The measurement results show that the eight-phase-level microlens arrays diffraction efficiency is as high as 93%.