用作多通道长波光谱仪的量子格栅红外光电探测器列阵

美国陆军研究实验室的研究人员制备出了一种可用作多通道长波红外光谱仪的量子格栅红外光电探测器列阵．这种量子格栅红外光电探测器列阵是利用在7μm～16μm波长范围内具有宽带吸收特性的量子阱红外光电探测器材料结构制备的．用这种量子阱红外光电探测器材料制备量子格栅红外光电探测器器件的好处是,在该材料吸收范围内的各个相关波长上的光散射,可以在每个器件中形成一种窄带探测。     

采用640×512元量子阱红外光电探测器阵列的手持式长波红外摄像机

据www．techbriefs.com网站报道,美国宇航局喷气推进实验室用640×512元的AlxGal-xAs／GaAs量子阱红外光电探测器（QWIP）阵列作为像传感器,研制了一种截止波长为9gm的手持式长波红外摄像机。在一个旨在研制高分辨率、高灵敏度红外摄像机的长期规划中,这种摄像机只是一个中间阶段产品。     

长波HgCdTe红外探测器的暗电流机理研究进展

介绍了HgCdTe红外探测器的发展历程,详细分析了长波HgCdTe红外探测器的暗电流机制、采用同时拟合方法对暗电流参数进行提取与分析,介绍了为降低暗电流的一些新的研究进展。     

长波HgCdTe光电二极管：n^＋在p上面的结构与p在n上面的结构的比较

从理论上ｎ＾＋在ｐ上和ｐ在ｎ上的ＨｇＣｄＴｅ光电二极管的性能再度进行了分析。假定光电二极管的性能是由于受俄歇机现控制的热发生的结果,对于工作于７７Ｋ,采用０．１ｅＶ基材料的两种类型的ＨｇＣｄＴｅ光电二极管,均考虑了结位置对Ｒ０Ａ积,光电增益以及噪声的影响。尤其是,详细分析了两种结构的作为截止波长的温度的函数的Ｒ０Ａ积。就假定的同质结基区掺杂浓度而言（对于ｎ＾＋在ｐ上的结构,Ｎａ＝５×１０＾１５ｃｍ     

回熔过程对HgCdTe长波红外光伏探测器的I-V性能的影响

对三种不同工艺的HgCdTe长波器件(标准工艺、回熔处理、离子注入后退火)的I-V性能分别进行测试,并通过理论计算与实验数据拟合提取上述器件参数,分析暗电流机制及导致暗电流变化的原因。文章中使用的暗电流机制的模型由扩散电流、产生-复合电流、缺陷辅助隧道电流和直接隧道电流组成。从拟合得到的器件参数中可以发现回熔过程中产生了大量的缺陷,导致缺陷辅助隧道电流、产生复合电流显著增加,器件反偏电阻减小,I-V性能变差。与离子注入后退火器件的性能变化相比,推测导致器件回熔后性能下降的原因是ZnS钝化层受热不稳定。     

用分子束外延法生长的Hg_(1-x)Cd_xTe制备的长波和中波红外光电二极管(上)

用分子束外延(MBE)生长的Hg_(1-x)Cd_xTe(0.20相似文献   

回熔过程对HgCdTe长波红外光伏探测器的Ⅰ-Ⅴ性能的影响

对三种不同工艺的HgCdTe长波器件(标准工艺、回熔处理、离子注入后退火)的Ⅰ-Ⅴ性能分别进行测试,并通过理论计算与实验数据拟合提取上述器件参数,分析暗电流机制及导致暗电流变化的原因.文章中使用的暗电流机制的模型由扩散电流、产生-复合电流、缺陷辅助隧道电流和直接隧道电流组成.从拟合得到的器件参数中可以发现回熔过程中产生了大量的缺陷,导致缺陷辅助隧道电流、产生复合电流显著增加,器件反偏电阻减小,Ⅰ-Ⅴ性能变差.与离子注入后退火器件的性能变化相比,推测导致器件回熔后性能下降的原因是ZnS钝化层受热不稳定.     

HgCdTe长波光电二极管列阵的等离子体修饰

报道了HgCdTe长波离子注入n+-on-p型光电二极管列阵低能氢等离子体修饰的研究成果.基于采用分子束外延(MBE)技术生长的HgCdTe/CdTe薄膜材料,通过注入窗口的光刻与选择性腐蚀、注入阻挡层的生长、形成光电二极管的B+注入、光电二极管列阵的低能氢等离子体修饰、金属化和铟柱列阵的制备等工艺,得到了氢等离子体修饰的n+-on-p型HgCdTe长波光电二极管列阵.从温度为78 K的电流与电压(I-V)和动态阻抗与电压(R-V)特性曲线中,发现经过低能氢等离子体修饰的HgCdTe红外长波光电二极管列阵动态阻抗极大值比未经过修饰处理的提高了1～2倍,并在反向偏压大于动态阻抗极大值所处的偏压时动态阻抗得到更为明显的提升.这表明低能氢等离子体修饰可以抑制HgCdTe光电二极管列阵暗电流中的带带直接隧穿电流Ibbt和缺陷辅助隧穿电流Itat,从而能提高长波红外焦平面探测器工作的动态范围和探测性能的均匀性.     

Bake stability of long-wavelength infrared HgCdTe photodiodes

The bake stability was examined for HgCdTe wafers and photodiodes with CdTe surface passivation deposited by thermal evaporation. Electrical and electrooptical measurements were performed on various long-wavelength infrared HgCdTe photodiodes prior to and after a ten-day vacuum bakeout at 80°C, similar to conditions used for preparation of tactical dewar assemblies. It was found that the bakeout process generated additional defects at the CdTe/ HgCdTe interface and degraded photodiode parameters such as zero bias impedance, dark current, and photocurrent. Annealing at 220°C under a Hg vapor pressure following the CdTe deposition suppressed the interface defect generation process during bakeout and stabilized HgCdTe photodiode performance.     

Tunneling in long-wavelength infrared HgCdTe photodiodes

We have generalized the existing expression for the trap-assisted tunneling current to include the effect of linearly varying electric field in the depletion region and self-consistently calculated steady-state trap occupation probability. We find that the magnitude and variation of current with voltage depend critically on these improvements.     

HgCdTe long-wavelength infrared photovoltaic detectors fabricated using plasma-induced junction formation technology

A long-wavelength infrared (LWIR) HgCdTe photodiode fabrication process has been developed based on reactive ion etching (RIE) plasma-induced p-to-n type conversion for junction formation. The process has been successfully applied to produce devices using both vacancy-doped and gold-doped liquid phase epitaxy (LPE)-grown p-type HgCdTe material with a cut-off wavelength of 10 μm at 77 K. The fabrication procedure is outlined and results are presented on completed devices that indicate the effect of variations in processing parameters. The fabricated devices have been characterized by measurements of the diode dark I-V characteristic over the temperature range 20–200 K, as well as by spectral responsivity measurements. Analysis of the device I-V data, variable area data, and modeling of diode dark current mechanisms indicates that gold-doped material results in higher performing devices compared to vacancy-doped material. Device performance is found to be strongly affected by trap-assisted tunneling currents and surface leakage currents at zero bias. Nonoptimum surface passivation is likely to be the major factor limiting performance at this early stage of device technology development.     

HgCdTe focal plane arrays for dual-color mid- and long-wavelength infrared detection

Raytheon Vision Systems (RVS, Goleta, CA) in collaboration with HRL Laboratories (Malibu, CA) is contributing to the maturation and manufacturing readiness of third-generation, dual-color, HgCdTe infrared staring focal plane arrays (FPAs). This paper will highlight data from the routine growth and fabrication of 256×256 30-μm unit-cell staring FPAs that provide dual-color detection in the mid-wavelength infrared (MWIR) and long wavelength infrared (LWIR) spectral regions. The FPAs configured for MWIR/MWIR, MWIR/LWIR, and LWIR/LWIR detection are used for target identification, signature recognition, and clutter rejection in a wide variety of space and ground-based applications. Optimized triple-layer heterojunction (TLHJ) device designs and molecular beam epitaxy (MBE) growth using in-situ controls has contributed to individual bands in all dual-color FPA configurations exhibiting high operability (>99%) and both performance and FPA functionality comparable to state-of-the-art, single-color technology. The measured spectral cross talk from out-of-band radiation for either band is also typically less than 10%. An FPA architecture based on a single-mesa, single-indium bump, and sequential-mode operation leverages current single-color processes in production while also providing compatibility with existing second-generation technologies.     

Thermal cycling-induced changes in excess dark current in very long-wavelength HgCdTe photodiodes at low temperature

We have observed cooldown-to-cooldown changes in the reverse-bias dark current of some very long-wavelength (cutoff >14 μm) HgCdTe P-on-n heterojunction photodiodes operated at very low temperatures (40–45 K). Other photodiodes in the same arrays are stable between cooldowns. The unstable ones have high dark currents, in the tail of the dark current distribution. Current-voltage analysis indicates that the high dark current is caused by trap-assisted tunneling and that the number of traps changes from cooldown to cooldown. Devices with negligible trap-assisted tunneling current, limited by diffusion and band-to-band tunneling currents at reverse bias, are stable between cooldowns. Both types of devices are stable within a given cooldown over periods of at least 24 h.     

替代衬底上的碲镉汞长波器件暗电流机理

基于暗电流模型,通过变温I-V分析长波器件(截止波长为9~10μm)的暗电流机理和主导机制.实验对比了不同衬底、不同成结方式、不同掺杂异质结构与暗电流成分的相关性.结果表明,对于B+离子注入的平面结汞空位n~+-on-p结构,替代衬底上的碲镉汞(HgCdTe)器件零偏阻抗(R0)在80 K以上与碲锌镉(CdZnTe)基碲镉汞器件结阻抗性能相当.但替代衬底上的HgCdTe因结区内较高的位错,使得从80 K开始缺陷辅助隧穿电流(I_(tat))超过产生复合电流(I_(g-r)),成为暗电流的主要成分.与平面n~+-on-p器件相比,采用原位掺杂组分异质结结构(DLHJ)的p~+-on-n台面器件,因吸收层为n型,少子迁移率较低,能够有效抑制器件的扩散电流.80 K下截止波长9.6μm,中心距30μm,替代衬底上的p~+-on-n台面器件品质参数(R0A)为38Ω·cm2,零偏阻抗较n-on-p结构的CdZnTe基碲镉汞器件高约15倍.但替代衬底上的p+-on-n台面器件仍受体内缺陷影响,在60 K以下较高的Itat成为暗电流主导成分,其R0A相比CdZnTe基n~+-on-p的HgCdTe差了一个数量级.     

Recent developments of high-complexity HgCdTe focal plane arrays at leti infrared laboratory

In this article, we present recent developments of the research in France at LETI infrared laboratory in the field of complex third-generation HgCdTe IRCMOS focal plane arrays (FPAs). We illustrate this with three prototypes of FPAs made at LETI, which have involved some technological improvements from the standard process today in production at Sofradir. We present, using molecular-beam epitaxy (MBE) growth, a 128 × 128 dual-band infrared (photodetector)-complementary metal oxide semiconductor (IRCMOS) with a pitch of 50 μm operating within 2–5 μm. Using the more conventional liquid-phase epitaxy (LPE) growth, we show a new generation of high-performance long linear arrays (1500 × 2; pitch, 30 μm) operating in medium-wavelength infrared (MWIR) or long-wavelength infrared (LWIR) bands based on a modular architecture of butted HgCdTe detection circuit and SiCMOS multiplexers. Finally, we present for the first time a megapixel (1000 × 1000) FPA with a pitch of 15 μm operating in the MWIR band that exhibits a very high performance and pixel operability.     

Effects of hydrogen on majority carrier transport and minority carrier lifetimes in long-wavelength infrared HgCdTe on Si

We present extended results on the use of a hydrogen plasma to passivate the effects of defects in long-wave ir HgCdTe/Si. Annealed and as-grown epilayers, in situ doped with indium, were exposed to a hydrogen plasma generated in an electron cyclotron resonance (ECR) reactor. Secondary ion mass spectrometry was used to measure the extent of hydrogen incorporation into the epilayers. Hall and photoconductive lifetime measurements were used to assess the efficacy of passivation. The passivation of defects responsible for the scattering and recombination of electrical carriers was observed for most ECR conditions over a range of dislocation densities.     

Planar p-on-n HgCdTe heterojunction mid-wavelength infrared photodiodes formed using plasma-induced junction isolation

Planar p-on-n HgCdTe heterojunction photodiodes have been fabricated using a plasma-induced type conversion process for device junction isolation. The technique is presented as a fully planar alternative technology to the commonly used mesa isolation structure. The starting material consisted of an indium-doped n-type mid-wavelength infrared (MWIR) HgCdTe absorbing layer that was capped by a 1-μm-thick wider bandgap arsenic-doped p-type layer. Junction-isolated p-on-n diodes were formed by selectively p-to-n type converting the p-type cap layer using a plasma process. Photodiode dark current-voltage measurements were performed as a function of temperature, along with noise and responsivity. The devices have cut-off wavelengths between 4.8 μm and 5.0 μm, exhibit diffusion-limited dark currents down to 145 K, give R₀A values greater than 1 × 10⁷Ω·cm² at 80 K and greater than 1 × 10⁵Ω·cm² at 120 K, and have negligible 1/f noise current at zero applied bias.