Doped silicon and NIS junctions for bolometer applications

We discuss the performance, of a normal metal hot electron bolometer (NHEB) that we have measured at 0.3 K. We found that the noise equivalent power was limited by the amplifier noise. To improve the NHEB power response and to make it more robust and reliable we propose to substitute the normal metal with heavily doped silicon. The heavily doped silicon behaves like a metal with lower carrier concentration and has a smaller electron–phonon thermal coupling. We have fabricated superconductor-doped silicon-superconductor contacts (S-Sm-S) and we have used them as thermometers and coolers.     

Terahertz detectors based on superconducting hot electron bolometers

Low noise terahertz(THz)heterodyne detectors based on superconducting niobium nitride(NbN) hot electron bolometers(HEBs)have been studied.The HEB consists of a planar antenna and an NbN bridge connecting across the antenna’s inner terminals on a high-resistivity Si substrate.The double sideband noise temperatures at 4.2 K without corrections have been characterized from 0.65 to 3.1 THz.The excess quantum noise factor β of about 4 has been obtained,which agrees well with the calculated value.Allan variance of the HEB has been measured,and Allan time up to 20 s is obtained using a microwave feedback method.Also,the intermediate frequency gain bandwidth(GBW)was measured using two dierent methods,resulting in same GBW value of about 3.5 GHz.     

Study of the dead layer in germanium for the CDMS detectors

We present new measurements on a Cryogenic Dark Matter Search (CDMS) detector with electron, neutron, and gamma sources. The measurements have been performed to investigate the dead layer of one of the CDMS Z-dependent Ionization Phonon germanium detectors. The dead layer has been studied at both charge electrodes and at different electric field intensities. We also present a method to remove the dependence of athermal phonon measurements on event position.     

室温红外探测器研究与进展

简要概述了室温红外探测器技术的最新研究现状,首先根据工作机理的不同对红外探测器进行了分类,详细阐述了室温红外探测器的优点所在;接着在给出了室温红外探测器典型结构的基础上,对这些典型结构进行了比较和讨论;给出了最近出现的几种新型探测器,介绍了其工作原理、制作工艺和主要性能指标;最后对室温红外探测器的发展方向进行了预测。     

锰钴镍氧薄膜热敏型多元红外探测器研制

通过光刻和湿化学腐蚀工艺,成功制作出规格为2×8的多元锰钴镍氧薄膜红外探测器件.测试表明,室温下锰钴镍氧薄膜材料负电阻温度系数达-3.8%K-1.10 Hz调制频率和±15 V电压偏置条件下,线列器件典型探测元黑体响应率为107 V/W,探测率为2×107cmHz1/2/W,8元器件响应不均匀度为5.9%.实验结果表明锰钴镍氧薄膜焦平面器件制备的可行性,有可能作为新型室温全波段探测器件得到应用.     

非制冷红外焦平面阵列读出电路的BCB牺牲层接触平坦化(英文)

研究了一种基于BCB材料的牺牲层接触平坦化技术,用于红外焦平面阵列Post CMOS工艺之前对读出电路表面的平坦化,以利于微测辐射热计微桥阵列与读出电路的集成。利用该方法成功将2μm的电路表面突起,平坦化为表面起伏56 nm的平面,可替代会给器件带来颗粒和损伤的化学机械抛光(CMP)技术。并在该平坦层上方成功进行了非晶硅敏感薄膜的沉积、微桥结构的图形化以及同时作为牺牲层的BCB的释放。通过实验研究了BCB膜层的厚度与转速、固化温度的关系,实验发现BCB的收缩率随温度小范围变化,约为30%。研究了BCB的等离子刻蚀特性,表明该材料适合用等离子刻蚀的方法进行接触孔的刻蚀和牺牲层释放。最后,利用BCB牺牲层接触平坦化技术成功地在读出电路(ROIC)芯片上制作了160×120面阵的非制冷红外焦平面阵列。     

Static Theory of a Self-Driven Photo-Thermoelectrical High-Temperature Superconductor Bolometer

At the present time, radiation detection in the far infrared with millisecond response time requires use of complicated technology to obtain mK-degree operating temperatures and very high quality, critical temperature materials (e.g., W, Al). It is also customary to use films of nanometer thickness in the manufacture of such devices. In this paper, we present theory and computations for the performance a composite high-temperature superconductor (HTSC)–thermolectric materials bolometer, operated at 77 K and with films of thickness around 1 . A practical device with performance comparable to available photoelectrical bolometers is investigated. The simplicity of the technology involved makes it an attractive proposition. A semimetal film leg (SML; e.g., BiSb) is connected in parallel with a HTSC leg (HTSCL; e.g., YBCO). The bolometer is operated in a photovoltaic mode with no external source of bias power. The thermoelectric voltage developed across the SML leg due to radiation absorbed on the sensitive area of the bolometer remains shorted till there is a sufficient temperature rise of the HTSCL so that its resistance becomes comparable to that of the SML. The voltage thus developed across the bolometer would drive an external electronic readout circuit.     

Fabrication of Robust Superconducting Granular Aluminium/Palladium Bilayer Microbolometers with Sub-Nanosecond Response

We provide a convenient recipe for fabricating reliable superconducting microbolometers as acoustic phonon detectors with sub-nanosecond response, using image-reversal optical lithography and dc-magnetron sputtering, and our recipe requires no chemical or plasma etching. Our approach solves the traditional problem for granular aluminium bolometers of unreliable (i.e., non-Ohmic) electrical contacts by sequentially sputtering the granular aluminium film and then a palladium capping layer. We use dc calibration data, the method of Danilchenko et al. (Acta Phys. Pol. A 103(4):325, [2003]) and direct nanosecond-pulsed photoexcitation to obtain the microbolometer’s characteristic current, thermal conductance, characteristic relaxation time, and heat capacity. We also demonstrate the use of the deconvolution algorithm of Edwards et al. (J. Phys. E Sci. Instrum. 22:582, [1989]) to obtain the phonon flux in a heat pulse experiment with nanosecond resolution.      

Surface Event Rejection of the EDELWEISS Cryogenic Germanium Detectors Based on NbSi Thin Film Sensors

Near-surface-events are a major limitation to the performance of cryogenic massive germanium heat and ionisation detectors for dark matter search, due to their incomplete charge collection. We present here a powerful method of surface event identification based on the transient heat signal of a Ge bolometer, equipped with two NbSi high impedance thin film sensors. Calibration runs using electrons and low energy gamma particles from a ¹⁰⁹Cd source show highly effective surface event rejection down to the heat threshold energy. Neutron and gamma source calibrations were realised to get information on the fiducial volume of the Ge absorber. First results from low background data taking are discussed.     

HERSCHEL—PACS Bolometer Arrays for Submillimeter Ground-Based Telescopes

The Herschel Space Observatory will carry onboard a new kind of bolometric architecture for the PACS (Photodetector Array Camera and Spectrometer) submillimeter photometer. These new generation CCD-like multiplexed bolometer arrays are buttable and enable the conception of large fully sampled focal planes either for space or for ground-based telescopes. We present here some development for ground-based applications in the context of the ARTEMIS (ARchitecture de bolomètres pour des TElescopes sub-MIllimétriques au Sol) project. We have developed an electro-thermal numerical model that simulates the performances of these semiconducting bolometers under specific ground-based conditions (different wavelengths and background powers for example). This model permits to determine the optimal parameters for each condition and shows that the bolometers can be background limited in each atmospheric transmission window between 200 and 450 microns. We also describe the optical system that provides a high optical efficiency in each submillimeter atmospheric window. Astronomical observations made with a prototype on the APEX telescope are presented.