利用迁移率谱技术研究p型碲镉汞材料

窄禁带碲镉汞(HgCdTe)是电子和空穴混合导电的多载流子体系材料,特别是对于p材料,由于电子和空穴的迁移率相差大约两个数量级(b=μe/μh≈102),更容易受到少数载流子电子的干扰,因此单一磁场的霍尔测试无法准确有效地给出p型材料的电学参数.通过变温变磁场的霍尔测试对p型HgCdTe材料的磁输运特性进行了测试,结合...     

"弱P型"和低迁移率n型碲镉汞体材料的迁移率谱研究

详细分析了两类碲镉汞(HgCdTe)材料的磁输运特性,并以此寻找两类材料的有效筛选方法.窄禁带HgCdTe是一种电子和空穴混合导电的多载流子体系材料.特别是"弱p型"材料,由于电子的迁移率比空穴的大两个数量级(b=μ/hμ≈102),更容易受到少数载流子(电子)的干扰,因此通过单一磁场的霍尔测试无法区分性能很差的低迁移...     

资料简介索引

红外技术 4001 碲镉汞的溅射研究 Mercury cadmium telluride sputtering research,R.H.Cornely, AD. A094 671,18p(1980). 在三靶射频溅射中,通过提高Hg蒸汽压及CdTe或Si衬底温度提高了(Hg,Cd)Te(CdTe占25克分子％)生成态溅射膜的迁移率。用4探针霍尔测量法测得在296和89K时电子迁移率分别为2200和3720厘米~2/伏秒,n型载流子浓度分别为5和2.8×10~(16)/厘米~3。     

Au掺杂碲镉汞气相外延生长及电学性能

采用气相外延技术生长Au掺杂的Hg_(1-x)Cd_xTe薄膜材料,利用范德堡法对薄膜材料进行电学性能表征.通过变温霍尔测量,分析了常规Au掺杂p型薄膜的霍尔系数和霍尔迁移率随温度的变化,利用二次离子质谱(SIMS)分析薄膜中Au的纵向分布趋势.讨论了三种反常p型薄膜的霍尔系数和霍尔迁移率随温度的变化.通过变磁场霍尔测量,分析了具有反型层Hg_(1-x)Cd_xTe薄膜的迁移率谱,证实了由于表面电子、体电子以及体空穴混合导电造成的反常霍尔性能.     

液相外延碲镉汞中砷离子注入与激活表征研究

As在HgCdTe材料中具有较小的扩散系数,可以形成较为稳定的结构,广泛应用于HgCdTe的p型掺杂。在p-on-n型碲镉汞红外探测器的制备中As掺杂是重要的制备方法。针对在制备过程中存在无法精确测量As激活率的问题,提出采用低温弱p型退火辅助差分霍尔测试的方法,获得了载流子浓度分布,从而通过与SIMS测试结果对比得到长、中波液相外延HgCdTe样品中As的激活率,并分析了退火等工艺对As掺杂后激活率的影响。     

碲镉汞p-n结光电二极管稳态特性的计算机模拟

参考文献[1]和[2]曾用电中性近似作为迭代初值,计算了p-n型碲镉汞光伏探测器的稳态特性,并讨论了计算中所采用的特别设计的差分方法的稳定性问题。本文改用n-p型结构,并采用耗尽层近似作为迭代初值,除载流子分布、电势分布和伏安特性外,还增加计算了零偏压电阻R_0和结电容C_j及其随某些参量(底板厚度、载流子迁移率、结的陡缓)的变化。在工艺上,把n型层注入到p型碲镉汞比把p型层注入到n型碲镉汞要方便,并可减     

掺砷碲镉汞的光致发光光谱和电学性质

碲镉汞的电学性能和光学性能直接决定探测器性能.对窄禁带掺砷碲镉汞进行了11 ～ 300 K的红外光致发光光谱和变温霍尔测量.对变温光致发光光谱进行了拟合分析,结果表明经通用的两步退火,样品不仅存在砷占碲位(AsTe)、汞空位(VHg)和TeHg-VHg对,还存在碲反位(TeHg).掺杂浓度越大,退火产生的TeHg-VHg对越多.变温霍尔分析进一步证明通用的两步退火后材料中存在TeHg,TeHg留在材料中使迁移率减小.     

HgCdTe的反常高电子迁移率

文中报道了碲镉汞的反常高电子迁移率。变磁霍尔测量和小光点扫描红外透射测量结果表明，反常高电子迁移率碲镉汞样品中存在导电非均匀性，这种导电非均匀性是横向组分严重偏析形成的负径向电子浓度梯度（电子浓度从晶片中心向周边减小）造成的。负径向电子浓度梯度的导电非均匀性使HgCdTe电子迁移率的测量值反常地高。     

碲镉汞材料中Hg空位、Au、As掺杂的研究进展

碲镉汞材料是制造红外探测器的基础,高性能红外探测器对碲镉汞材料的要求越来越高。为了提升器件性能,必须提高碲镉汞材料的电学性能。而掺杂是一个很好的选择。碲镉汞材料掺杂可以分为n型和p型两种。对于n型掺杂来说,In是一种理想的掺杂剂,其掺杂研究目前已比较成熟。相对而言,p型掺杂研究还不是那么深入。Hg空位、Au、As掺杂均为碲镉汞材料中常见的p型掺杂手段。通过分析和总结近些年的部分相关文献,介绍了碲镉汞材料中Hg空位、Au、As掺杂的研究进展。     

碲镉汞的热处理

碲镉汞晶体的化学计量比和自由载流子浓度是通过热处理来调整的。即是在组分的蒸汽下,从接近固化温度时慢慢冷却到室温。碲镉汞保持在石英管的低温处,它可以在短时间内使p型材料变成n型材料。     

Maximum entropy mobility spectrum analysis of HgCdTe heterostructures

We report on mobility spectrum analysis of p-type HgCdTe using a new maximum entropy algorithm termed full MEMSA (f-MEMSA). The algorithm is the first that separates the constraints on the transverse and longitudinal components of the conductivity tensor, which results in a higher resolution, compared to other MEMSA algorithms. Compared to the Lakeshore c-QMSA algorithm, f-MEMSA demonstrated a lower detection limit and smaller errors for estimations on synthetic data sets. f-MEMSA was applied to experimental data measured on p-type Hg_0.77Cd_0.23Te, measured between T=30 K and 300 K and for an applied magnetic field between μ₀H=0 T and 9 T. Despite the demonstrated high performance of f-MEMSA on synthetic data, we observed several nonphysical contributions, such as low mobility electrons and high mobility holes. A systematic study of different sample geometries and growth methods showed that the high mobility holes, so-called mirror peaks, can be attributed to finite contact size effects. It also indicated that the low mobility electrons appear in the mobility spectrum as a consequence of a limitation in the application of mobility spectrum analysis (MSA) to vacancy-doped HgCdTe, which is consistent with a magnetic freezeout of the holes at high magnetic fields.     

原位As掺杂p型碲镉汞薄膜的制备研究

非本征p 型掺杂碲镉汞材料可以有效克服少子寿命偏低等问题,提高长波和甚长波红外焦平面器件的性能。本文重点阐述了As 掺杂实现p型掺杂的基础性原理,以及其制备方法,为p-on-n碲镉汞材料器件研究提供依据。     

Transport properties of reactive-ion-etching-induced p-to-n type converted layers in HgCdTe

In this work, the effect of the reactive ion etching (RIE)-induced p-to-n type conversion process on the transport properties of HgCdTe is investigated. Magnetic-field-dependent differential Hall and resistivity measurements have been performed to determine the n-type doping profile and temperature-dependent transport properties of carriers resulting from the RIE-induced type conversion. The study examined Hg_1-xCd_xTe with x=0.23 and x=0.31 for both vacancy-doped and gold-doped p-type epilayers grown by liquid phase epitaxy (LPE) on lattice-matched CdZnTe, which were partly converted to n-type by a RIE process. Analysis using quantitative mobility spectrum analysis (QMSA) reveals that RIE type conversion results in a damaged surface layer characterized by moderate mobility electrons and a bulk n-type region exhibiting higher electron mobility. The surface and bulk electrons show a distinct temperature dependence. It can be observed that, generally, the concentration and mobility of the surface electrons are similar for all samples studied and are independent of temperature in the measured temperature range. In contrast, the bulk electrons exhibit classical behavior with characteristics that are strongly dependent on temperature and consistent with high-quality HgCdTe material. Differential Hall results indicate that the n-type dopants resulting from the RIE process are distributed into the sample via a diffusion process. The results suggest a p-to-n type conversion mechanism involving neutralization of the p-type dopants and diffusion of extrinsic n-type dopants from the surface.     

Si基HgCdTe材料的电学特性研究

文章研究了Si基分子束外延HgCdTe原生材料、P型退火材料和N型退火材料的霍耳参数、少子寿命等材料电学特性。研究发现，晶格失配导致Si基HgCdTe材料原生材料和N型退火材料迁移率低；Si基原生HgCdTe材料属于高补偿材料，但高补偿性并非材料的固有特性，通过P型退火可使材料变为低补偿材料，迁移率得到提高。采用分子束外延方法制备的3in Si基HgCdTe材料电学性能与GaAs基HgCdTe材料相比，性能还有待提高。改进分子束外延生长工艺提高HgCdTe质量，从而进一步提高迁移率，是Si基外延研究的关键。     

金掺杂碲镉汞红外探测材料及器件技术

采用金掺杂替代作为深能级缺陷中心的汞空位,可明显提高P型碲镉汞材料少子寿命,进而降低以金掺杂P型材料为吸收层n-on-p型碲镉汞器件的暗电流,明显提升了n-on-p型碲镉汞器件性能,是目前高灵敏度、高分辨率等高性能n-on-p型长波/甚长波以及高工作温度中波碲镉汞器件研制的一种技术路线选择。本文在分析评述金掺杂碲镉汞材料现有研究技术要点的基础上,结合昆明物理研究所目前的研究成果,总结了碲镉汞金掺杂相关工艺技术,重点分析了金掺杂对碲镉汞器件性能的影响。     

HgCdTe/CdTe heterostructure diodes and mosaics

This paper discusses the results of a study of the properties of HgCdTe/CdTe heterostructure diodes and mosaics. In this study, p-type HgCdTe epi-layers on the order of 20 µm were grown on CdTe substrates by a liquid-phase epitaxial (LPE) technique. These layers normally had a carrier concentration of 5 × 10¹⁶/cm³and a mobility of 400 cm²/V . s at 77 K. The n⁺-p junction was formed by boron ion implantation, and standard photolithographic techniques were used for the device fabrication. The diodes with no antireflection coating had a typical quantum efficiency of 40 percent. The 1/fnoise knee was on the order of 10 Hz at zero bias. Surface leakage seemed to be the dominant component for diodes at temperatures less than 77 K. From mosaic studies, it was found that the spectral spread was less than ±0.3 µm for an area as large as 12 × 20 mm. The study indicates that LPE offers a viable technique for producing high-quality HgCdTe epi-layers on CdTe.     

碲镉汞富碲垂直液相外延技术

研究了碲镉汞富碲垂直液相外延技术.在研究该关键技术的过程中,提出了一种方法以检查外延前(Hg1-xCdx)1-yTey母液的均匀性.并且,通过减小生长腔体中的自由空间,对气体的对流和汞回流进行了抑制,及通过改进工艺过程中的温度控制方式来应对因对流和汞回流而造成的生长温度不确定性.在解决上述关键技术后,实现了碲镉汞垂直液相外延工艺的稳定性,所外延的中波碲镉汞材料的组分可重复性做到了±0.005,厚度控制能力达到了±5μm ,40×30mm2外延材料的横向组分均匀性(相对均方差)小于1.3×10-3,同生长批次材料片与片之间的组分和厚度差异分别小于0.001和1μm.在10mm线度上,表面起伏小于1μm.经热处理后,中波汞空位p型材料在77K下具有较高的空穴迁移率.另外,和水平推舟技术相比,垂直碲镉汞液相外延在提供大批量和大面积相同性能材料方面具有明显的优势,这对于二代碲镉汞红外焦平面批生产技术和拼接型超大规模红外焦平面技术的发展都具有重要的意义.     

碲镉汞p型接触孔湿法腐蚀工艺研究

针对碲镉汞芯片p型接触孔湿法腐蚀工艺进行研究,采用不同条件的湿法腐蚀工艺完成碲镉汞p型接触孔制备,通过扫描电子显微镜和激光扫描显微镜分析腐蚀后的接触孔表面形貌,电学接触性能通过伏安特性曲线表征。实验结果表明,传统湿法腐蚀工艺在碲镉汞芯片接触孔制备过程中存在钻蚀严重和均匀性不好等问题,针对以上问题提出了一种超声辅助湿法腐蚀工艺,制备出形貌及均匀性较好的p型接触孔。