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对研制的10 μm中心距2560×2048元InGaAs焦平面探测器组件进行光电性能测试,测试条件如表1所示(表中,1 in=2.54 cm)。
Item Value Item Value Black body temperature/K 900 Black body aperture/in 0.1 Distance/cm 60 Blackbody radiated power/W 1.65×10−11 Ambient temperature/℃ 22 Ambient humidity 23% Operating temperature/K 276 Circuit gain 0.8 Integral time/ms 100 Integral capacitance/fF 15 Table 1. Test conditions of 2560×2048 InGaAs focal plane arrays
如图11所示为焦平面的响应光谱曲线,从图中可以看出,2560×2048元InGaAs焦平面光谱响应范围为0.80~1.71 µm。
焦平面黑体响应信号如图12所示,测得黑体响应信号Vs=1.071 V,响应非均匀性为3.81%,盲元率0.26%。
Figure 12. Measured result of response signal of FPAs. (a) Pixel signal map; (b) Signal statistical distribution
焦平面噪声测试结果如图13所示,噪声电压为1.02 mV。
Figure 13. Measured result of noise of FPAs. (a) Pixel noise map; (b) Noise statistical distribution
焦平面的响应率R、探测率D*和量子效率η分别为:
式中:Vs为平均信号值;VN为平均噪声值;Cint为积分电容;Tint为积分时间;Av为电路增益,取值0.8;G因子为光谱因子,值取78;h为普朗克常数;c为真空光速;
${\lambda _p} $ 为峰值波长,为1.6 μm。根据测得的光谱响应、信号、噪声,计算得到焦平面的响应率为0.95 A/W,量子效率为73.7%,峰值探测率为1.11×1013 cm·Hz1/2/W。采用了高动态范围(High-Dynamic Range, HDR)技术进行试验,通过两次或多次采样(Multiple Capture),当目标物的光强时,采用短积分时间Tint1;当目标物的光弱时,采用长积分时间Tint2,综合得到整个目标内的光强分布,获得大动态范围。采用短波红外激光器(MIL-1342 nm,200 mW)照到墙壁上,形成圆斑区域强光,读出电路饱和信号Vsat约为1.85 V。采用HDR技术,读出电路试验片Tint1=0.06 ms、Tint2=100 ms,成像图像如图14所示:等效的饱和信号约为2.604 V,动态范围增大到128.1 dB。
如图15所示,采用2560×2048元InGaAs焦平面探测器组件进行成像验证。如图16所示,短波红外成像可以清晰地辨别液位、穿透硅片对背后的火焰成像,以及具有分辨不同物质的能力。
2560×2048 short-wave infrared InGaAs focal plane detector (Invited)
doi: 10.3788/IRLA20210941
- Received Date: 2021-12-09
- Rev Recd Date: 2022-02-14
- Accepted Date: 2022-02-24
- Publish Date: 2022-04-07
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Key words:
- InGaAs /
- focal plane /
- short-wave infrared /
- detectivity /
- dark current
Abstract: The new generation of aerospace remote sensing instruments are developing towards high spatial resolution, high energy resolution, and high time resolution. Its core components are high-performance large-scale small-pixel short-wave infrared InGaAs focal plane detectors. The latest research progress in the design and fabrication of high-density InGaAs detector arrays was reported, and hybrided with matching Si-CMOS readout circuits to form a focal plane. The breakthroughs in dark current and noise suppression of high-density small-pixel detectors , megapixel focal plane flip chip interconnection and other key technologies were focused. The new flip chip interconnection technologies such as high flatness chip surface shape control, indium bumps convex morphology and high consistency control, and high-density flip chip interconnection control were solved. Developed 10 μm pitch 2560×2 048 focal plane detectors, which D* was better than 1.0×1013 cm·Hz1/2/W, the response non-uniformity was better than 3%, the effective pixel rate was better than 99.7%, and the dynamic range was better than 120 dB. This focal plane was used for laboratory demonstration imaging, and the picture was clear.