Growth of MOCVD HgCdTe heterostructures for uncooled infrared photodetectors
Growth of MOCVD HgCdTe heterostructures for uncooled infrared photodetectors
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用于非制冷红外光电探测器的 MOCVD HgCdTe 异质结构的生长
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
A. Rogalski
中科院分区：
文献类型：
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作者：
A. Piotrowski;P. Madejczyk;W. Gawron;K. Kłos;J. Pawluczyk;M. Grudzien;J. Piotrowski;A. Rogalski
本文介绍了VIGO/MUT（Military University of Technology）MOCVD实验室在GaAs/CdTe衬底上生长Hg 1 −xCdxTe（HgCdTe）多层异质结的最新进展。建立了单层和复杂多层异质结构生长的最佳条件。碲镉汞外延的关键阶段之一是碲镉汞在砷化镓衬底上的成核。成功的复合衬底已获得与合适的衬底制备，衬垫和基座处理，适当的控制背景通量和适当的成核条件。另一个关键阶段是相互扩散多层工艺（IMP）。器件质量的碲镉汞异质结构的生长需要完全均匀化的碲镉汞对保持在同一时间合适的组成和掺杂分布的锐度。这需要IMP对非常薄并且在短时间内生长。砷和碘已被用于受体和供体掺杂。合适的生长条件和生长后退火对于稳定和可再现的掺杂是必不可少的。原位退火似乎是足够的碘掺杂在任何所需的水平。相比之下，具有接近100%活化的高效As掺杂需要在接近饱和的汞蒸气下进行非原位退火。因此，我们能够生长多层全掺杂（100）和（111）异质结的各种红外器件，包括光电导体，光电磁和光伏探测器。目前的非制冷长波红外器件是基于多结光伏器件。描述了器件制作的工艺步骤。结果表明，近BLIP性能是可能实现在230 K的光学浸没。这些器件作为7.8-9.5 μm探测器特别有前途，表明有可能实现10 cmHz/W以上的探测率。
In the paper recent progress at VIGO/MUT (Military University of Technology) MOCVD Laboratory in the growth of Hg1−xCdxTe (HgCdTe) multilayer heterostructures on GaAs/CdTe substrates is presented. The optimum conditions for the growth of single layers and complex multilayer heterostructures have been established. One of the crucial stages of HgCdTe epitaxy is CdTe nucleation on GaAs substrate. Successful composite substrates have been obtained with suitable substrate preparation, liner and susceptor treatment, proper control of background fluxes and appropriate nucleation conditions. The other critical stage is the interdiffused multilayer process (IMP). The growth of device-quality HgCdTe heterostructures requires complete homogenization of CdTe-HgTe pairs preserving at the same time suitable sharpness of composition and doping profiles. This requires for IMP pairs to be very thin and grown in a short time. Arsenic and iodine have been used for acceptor and donor doping. Suitable growth conditions and post growth anneal is essential for stable and reproducible doping. In situ anneal seems to be sufficient for iodine doping at any required level. In contrast, efficient As doping with near 100% activation requires ex situ anneal at near saturated mercury vapours. As a result we are able to grow multilayer fully doped (100) and (111) heterostructures for various infrared devices including photoconductors, photoelectromagnetic and photovoltaic detectors. The present generation of uncooled long wavelength infrared devices is based on multijunction photovoltaic devices. The technology steps in fabrication of devices are described. It is shown that near-BLIP performance is possible to achieve at ≈ 230 K with optical immersion. These devices are especially promising as 7.8–9.5-μm detectors, indicating the potential for achieving detectivities above 10 cmHz/W.