Status of the MBE technology at leti LIR for the manufacturing of HgCdTe focal plane arrays

This paper presents recent developments that have been made in Leti Infrared Laboratory in the field of molecular beam epitaxy (MBE) growth and fabrication of medium wavelength and long wavelength infrared (MWIR and LWIR) HgCdTe devices. The techniques that lead to growth temperature and flux control are presented. Run to run composition reproducibility is investigated on runs of more than 15 consecutively grown layers. Etch pit density in the low 10⁵ cm⁻² and void density lower than 10³ cm⁻² are obtained routinely on CdZnTe substrates. The samples exhibit low n-type carrier concentration in the 10¹⁴ to 10¹⁵ cm⁻³ range and mobility in excess of 10⁵ cm²/Vs at 77 K for epilayers with 9.5 μm cut-off wavelength. LWIR diodes, fabricated with an-on-p homojunction process present dynamic resistance area products which reach values of 8 10³ Ωcm² for a biased voltage of −50 mV and a cutoff wavelength of 9.5 μm at 77 K. A 320 × 240 plane array with a 30 μm pitch operating at 77 K in the MWIR range has been developed using HgCdTe and CdTe layers MBE grown on a Germanium substrate. Mean NEDT value of 8.8 mK together with an operability of 99.94% is obtained. We fabricated MWIR two-color detectors by the superposition of layers of HgCdTe with different compositions and a mixed MESA and planar technology. These detectors are spatially coherent and can be independently addressed. Current voltage curves of 60 × 60 μm² photodiodes have breakdown voltage exceeding 800 mV for each diode. The cutoff wavelength at 77 K is 3.1 μm for the MWIR-1 and 5 μm for the MWIR-2.  

256×1甚长波量子阱红外焦平面研究

GaAs/AlGaAs量子阱红外探测器由于其所依据的GaAs基材料较为成熟的材料生长和器件制备工艺，使其特别适合于高均匀性、大面积红外焦平面的应用。报道了甚长波256×1元GaAs/AlGaAs多量子阱红外焦平面器件的研制成果, 探测器的峰值波长为15 μm,响应带宽大于1.5 μm。在40 K工作温度下，器件的平均黑体响应率Rp=3.96×106 V/W, 平均黑体探测率为D*=1.37×109 cm·Hz1/2/W, 不均匀性为11.3%, 并应用研制的器件获得了物体的热像图。  

离子注入型硅掺砷阻挡杂质带长波红外探测器的研究

研究了基于离子注入技术制备硅掺砷阻挡杂质带探测器的工艺，通过优化工艺条件和相关器件的结构与材料参数，制造了具有良好光电响应性能的长波红外探测器。在温度5 K，-3.8V工作偏压下，探测器的峰值响应波长为23.8μm，黑体响应率为3.7A/W，3.2V时最大探测率为5.2×10¹³ cm?Hz^1/2/W。性能指标堪与文献报道的结果相媲美甚至更好，展示了离子注入工艺在制作阻挡杂质带探测器方面的潜在优势，特别是离子注入工艺与目前的微电子电路技术相兼容，能将探测器与读出电路集成到一块芯片上，在降低成本的同时提高探测器成像性能。  

新型亚波长陷光结构HgCdTe红外探测器研究进展

综述了近几年来亚波长陷光结构HgCdTe红外探测器研究进展.系统介绍了一种结合有限元方法与时域有限差分方法对红外探测器的“光”“电”特性进行联合模拟和设计方法,以及基于这种新的数值模拟方法对亚波长人工微结构HgCdTe红外探测器的模拟和分析结果.理论分析和实验研制数据均显示这种新型亚波长人工微结构结构具有很好的陷光特性,在提高长波红外探测器性能方面具有潜在应用前景.