红外光导探测器组件的串音研究

作为目标探测与成像系统的核心器件,红外探测器组件的空间分辨能力会直接影响探测系统的成像质量。通常使用调制传递函数(Modulation Transfer Function,MTF)对该能力进行评估。而探测器组件的电学串音和光学串音则是影响其MTF的主要因素。利用锁相系统测试了红外探测器组件的电学串音,同时用一套弥散斑直径为30μm的红外小光点测试系统测试了红外探测器组件的线扩展函数(Line Spread Function,LSF)以评价其光学串音。测试结果表明,11.5~12.5μm波段探测器的光学串音明显比8.0~9.0μm波段探测器的大。最后对测试结果进行了分析,为红外探测器组件的光学串音设计提供了参考。     

不同结构长波红外探测器组件的MTF分析

红外探测器组件作为目标探测和成像系统的核心器件,其空间分辨能力直接影响着探测系统的成像质量.评估探测器组件空间分辨能力时,常使用调制传递函数(MTF),而不同的探测器组件结构与其MTF直接相关.介绍了一套弥散斑直径为30μm的红外小光点测试系统,采用扫描狭缝法测试不同结构红外探测器组件的MTF.测试结果表明叠层电极结构侧面存在的光响应会导致线扩散函数(LSF)展宽和次峰等现象,从而造成探测器组件MTF下降,同时0.17 mm和0.30 mm两种芯片和滤光片间距对于探测器组件MTF的影响甚微,该结果为红外探测器组件杂光抑制设计提供了参考.     

多元红外光导探测器电子学串音研究

在多元红外探测器的应用中,串音是影响探测器性能的一个重要因素。其中,多元红外光导探测器的电子学串音主要由探测元间的接地电阻引起。通过对光导探测器工作电路的原理分析,得出多元红外光导探测器的电子学串音与探测元间接地电阻的阻值成正比,与偏置电阻的阻值成反比,且与原信号反相的结论,并设计了电子学串音测试原理电路进行了实验测试。测试结果验证了理论分析的正确性。通过理论推导和实验测试证明：在接地电阻一定时,通过提高偏置电阻来抑制电子学串音的方法是可行的。     

HgCdTe光导探测器的优化设计

利用牛顿迭代法,在一维理论的基础上,计算机模拟优化设计了工作在8～14μm波段HgCdTe光导探测器的各项参数。结果表明,器件厚度取6μm,长度取100～150μm,环氧树脂胶粘层<3μm,净掺杂浓度取1.4×10~(15)cm~(-3),表面复合速度取500cm/s,电场强度取10V/cm为佳。该法亦可使用于其他光导探测器的优化设计中。     

红外探测器组件的结构

针对当今实用的红外探测器组件结构，根据应用场合致冷方式的不同作了简明的分类，并阐述各自的环境特点和应用方向。     

线扩散函数法用于SPRITE探测器调制传递函数测试

在ＳＰＲＩＴＥ探测器的研制和生产检验中,对其调制传递函数（ＭＴＦ）进行测试,可以分析和评价探测器的空间分辨率。文中将线扩散函数法用于该方面的测试,描述了一般的光路安排和自动测试方案,而且考虑了测试用光学投影系统对探测器ＭＴＦ测试的影响,以及相应的测试、补偿方法。     

光学浸没型双色HgCdTe光导探测器

本文利用光学浸没原理以及叠层双色探测器工作原理,研制出浸没型3μm～5μm,8μm～12μm双色HgCdTe光导探测器.3μm～5μm探测器峰值探测率可达10~(11)cmHz~(1/2)/W;8μm～14μm探测器峰值探测率达7.0×10~(10)cmHz~(1/2)W.峰值响应率可达10~3V/W.     

长波大面积HgCdTe光导红外探测器的研究

研制的长波大面积HgCdTe光导红外探测器的面积为2.1×2.1mm~2,在80K时探测率D_p~*=1.86×10~(10)cmHz~(1/2)W~(-1),响应率R_p=386VW~(-1),长波限λ_(co)(50%)>18μm.还研制了带有低温聚光器组合件结构的新型探测器,D_p~*=7.3×10~(10)cmHz~(1/2)W~(-1),λ_(co)(50%)>16μm.     

微透镜和高Tc超导红外探测器组件

本文首次报道了利用微透镜阵列来提高ＹＢＣＯ高Ｔｃ超导薄膜红外探测器的光响应特性，介绍了利用光刻／离子束刻蚀的方法制作单片线列石英微透阵列的工艺以及制备线列ＹＢＣＯ高Ｔｃ超导薄膜红外探测器的方法，并将所制的石英微透镜阵列应用于ＹＢＣＯ超导器件。     

一种长波红外光导探测器CMOS电路设计

CMOS 电路是高输入阻抗,而长波红外光导探测器是低阻抗,实现低阻抗红外光导探测器与CMOS 电路的良好匹配,是目前长波红外探测器高性能成像的关键技术。文中设计了一种能在低温下工作的低阻抗红外光导探测器CMOS 电路,差分放大器采用正负电源供电,在输入级采用桥式输入方式,该电路第一级采用1M的负反馈电阻实现信号放大,第二级放大采用正端放大方式,输入级、第一级放大、第二级放大均采用直接耦合方式。测试结果表明,该放大器与长波红外低输入阻抗光导探测器连接后能正常工作,总放大倍数大于1 万倍,3 dB 带宽大于4 kHz,等效输入电压噪声小于1.5 V,有效地解决了低阻抗光导探测器与高阻CMOS 电路的匹配问题。     

A comparison of interdigital and straight structures for a photoconductive detector

Photoconductive interdigital planar devices were realized together with conventional straight structures on the same GaAs-SI wafer. The performances of the two kinds of devices are compared and it is shown that the interdigital geometry exhibits an enhanced sensitivity with a time response similar to the straight-structure one.     

Demodulation of low-level broad-band optical signals with semiconductors: Part II—Analysis of the photoconductive detector

A fast response photoconductor with a high frequency bias supply is considered as an envelope detector for optical signals. The sensitivity is studied and compared with that of the diode demodulator. The ratio of SNR for the two devices is equal to the photocurrent gain. It is shown to be theoretically possible to achieve enough current gain to overcome the noise of the following amplifier. The current gain comes from two effects. One is a true photocurrent gain in the semiconductor itself, which can exceed unity if the microwave field reverses before the photocarriers are swept out. It can be as high as the number of times the photocarriers traverse the photoconductor before they recombine. The impedance transformation from the high resistance of the detector to the amplifier input gives additional current gain. Analysis of gain-bandwidth limitations reveals no restriction imposed by material parameters, in contrast to the case of dc bias. With RF bias, blocking contacts to the crystal are useable and the relationship between material resistivity and gain-bandwidth avoided. The limiting parameters are the signal bandwidth and the bias supply frequency, the device current gain being limited to the square of the Q value of the circuit. The effect of G-R noise is also considered and conditions derived under which it is unimportant. The two cases of a photoconductor in a rectangular waveguide and in a cavity are studied in more detail, and design equations relating sensitivity to the material and to the circuit parameters are deduced. For bandwidths up to at least 1 kMc, the photoconductor in the cavity can greatly outperform the photodiode. Its sensitivity can approach that of the photomultiplier with a high efficiency cathode, which opens the possibility of extending this high performance into the infrared.     

Analysis of microwave characteristics of photoconductive IC structures

A one-dimensional analytic solution for the microwave photoresponse of an optically modulated semiconductor channel is presented. This extends the existing treatments by including the effects of nonuniform channel cross sections and conductivity, nonuniform optical illumination, field-dependent mobilities, nonzero dielectric relaxation times, arbitrary electrical and optical excitation frequencies, and full coupled bipolar carrier transport. The solution is continuous over the full range of electric field intensities and thereby describes both the saturated and nonsaturated regimes of the photocurrent. Only the low-level generation case is considered, and trapping effects and diffusion are not included. This model allows the effects of optical stimulation in many typical IC structures to be assessed from dc up through the microwave range of frequencies.     

背景辐射对甚长波碲镉汞光导器件性能的影响

通过对甚长波碲镉汞器件的信号、噪声、有效寿命等的测试分析,研究背景辐射对甚长波器件性能的影响.利用冷光阑和黑体照射改变器件接收的背景辐射,设计并搭建了变背景有效寿命测试装置.改变背景辐射,测试甚长波器件的电阻、信号、噪声、噪声频谱、有效寿命.测量结果表明,增加立体角为30°的冷光阑后,随着背景辐射的减小,器件的电阻、信号、噪声、探测率等都有不同程度的增加;噪声频谱测试证明,1 kHz频率处的噪声主要是产生-复合噪声;改变黑体温度的变背景的有效寿命测试结果证明,背景辐射对寿命的影响很大,背景辐射减小,光生载流子的有效寿命增加.分析甚长波器件表面和体内的S-R复合、俄歇复合、辐射复合等复合机制,利用非平衡载流子和器件有效寿命理论对器件的寿命和产生复合噪声随背景辐射的变化进行理论计算,计算结果与实验结果存在一定的差异,但在随背景辐射变化的趋势上一致,并对两者的差别进行了分析.     

HgCdTe光导探测器比探测率的特性分析

从信号和噪声两个方面分析了HgCdTe光导探测器自身温度变化对比探测率D*的影响,并在理论层面上对比探测率的表达式进行了推导。理论分析表明:温度变化影响载流子的浓度和寿命,从而影响信号与噪声的大小,降低探测器的温度可使得探测器的比探测率得到一定程度的提高。通过MATLAB仿真,分析了组分和厚度的变化对Hg1-xCdxTe光导器件的截止波长和峰值波长的影响情况,为使HgCdTe光导探测器在工作波段内有较高的探测响应,当探测器工作在某一温度,应选择合适的组分x和厚度d。     

红外探测器用蓝宝石滤光片焊接工艺研究

针对某型号探测器组件上用的Al2O3蓝宝石滤光片与可伐冷头钎焊的成品率低、后期失效问题突出等问题展开研究,找到了影响滤光片焊接成品率的几个关键因素,并针对这些因素提出解决方案,并通过一系列环境试验验证其可靠性,大幅提升了宝石窗口密封焊接工艺成品率。     

Radiation effects on a GE:GA photoconductive detector

We have investigated radiation effects on a Ge:Ga photoconductive infrared detector at low photon background level of 4×10⁸ ph cm^?2s^?1, using Cobalt 60 as a gamma ray source. The irradiation immediately induced spike noises which degrded NEP (short term effect), while it gradually increased responsivity (long term effect). After the removal of the gamma ray source, the spikes disappeared while the responsivity still stayed in a higher level and gradually decreased with a time scale of several hours. The responsivity-change-rate before and after the irradiation is smaller for a higher bias voltage. Finally we have made the first trial to cure the long term effect, using a flashing procedure and have found out its effectiveness.