共查询到18条相似文献,搜索用时 125 毫秒
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通过改进推舟液相外延技术,成功地在(211)晶向Si/CdTe复合衬底上进行了HgCdTe液相外延生长,获得了表面光亮的HgCdTe外延薄膜.测试结果表明,(211)Si/CdTe复合衬底液相外延HgCdTe材料组分及厚度的均匀性与常规(111)CdZnTe衬底HgCdTe外延材料相当;位错腐蚀坑平均密度为(5~8)×105 cm-2,比相同衬底上分子束外延材料的平均位错密度要低一个数量级;晶体的双晶半峰宽达到70″左右.研究结果表明,在发展需要低位错密度的大面积长波HgCdTe外延材料制备技术方面,Si/CdTe复合衬底HgCdTe液相外延技术可发挥重要的作用. 相似文献
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通过改进推舟液相外延技术,成功地在(211)晶向Si/CdTe复合衬底上进行了HgCdTe液相外延生长,获得了表面光亮的HgCdTe外延薄膜.测试结果表明,(211)Si/CdTe复合衬底液相外延HgCdTe材料组分及厚度的均匀性与常规(111)CdZnTe衬底HgCdTe外延材料相当;位错腐蚀坑平均密度为(5~8)×105 cm-2,比相同衬底上分子束外延材料的平均位错密度要低一个数量级;晶体的双晶半峰宽达到70″左右.研究结果表明,在发展需要低位错密度的大面积长波HgCdTe外延材料制备技术方面,Si/CdTe复合衬底HgCdTe液相外延技术可发挥重要的作用. 相似文献
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文章叙述了第三代红外焦平面中所需求的碲镉汞分子束外延(MBE)的一些研究成
果。对GaAs、Si基大面积异质外延、表面缺陷抑制、p 型掺杂等MBE的主要难点问题进行了阐述。研究表明, 3 in材料的组分均匀性良好,组分x的偏差为0. 5%。晶格失配引发的孪晶缺陷可以通过合适的低温成核方法得到有效的抑制。在GaAs和Si衬底上外延的HgCdTe材料的(422) x射线衍射半峰宽( FWHM)的典型值为60~80arc·sec。大于2μm缺陷的表面密度可以控制在小于300cm- 2水平。研究发现As的表面黏附系数很低,对生长温度十分敏感,在170℃下约为1 ×10- 4。通过合适的退火,可以实现As的受主激活。采用碲镉汞多层材料已试制了长波n2on2p与p2on2n型掺杂异质结器件以及双色红外短波/中波焦平面探测器,本文报道了一些初步结果。 相似文献
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利用气相外延技术在CdZnTe衬底上生长Hg1-xCdxTe薄膜材料,通过在不同晶向、不同极性、不同晶向偏离角度CdZnTe衬底上的外延结果发现,CdZnTe衬底对外延形貌的影响非常大。(111)面衬底上外延形貌明显优于(211)面衬底的外延形貌。对于同是<111>CdZnTe晶向的衬底,(111)Cd面CdZnTe衬底上的外延形貌明显优于(111)Te面。对于(111)Cd面CdZnTe衬底,当晶向偏离角度不同时,其外延形貌也有差异,晶向偏离角越小表面形貌越好。 相似文献
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报道了使用分子束外延(Molecular beam epitaxy,MBE)技术,在(211)B碲镉汞(CdZnTe,CZT)衬底上生长中长波双色碲镉汞(HgCdTe,MCT)薄膜材料,生长温度为180℃,研究了双色碲镉汞薄膜材料衬底脱氧技术、分子束外延薄膜生长温度与缓冲层生长等关键技术,实现了中长波双色碲镉汞薄膜生长,外延薄膜采用相差显微镜、扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FTIR)、二次离子质谱仪(SIMS)及X射线衍射仪(XRD)对薄膜的表面缺陷、厚度、组分及其均匀性、薄膜纵向组分以及晶体质量进行了表征,表面缺陷数量低于600 cm-2,组分(300 K测试)和厚度均匀性分别为?x≤0.001、?d≤0.9μm,X-Ray双晶衍射摇摆曲线FWHM=65 arcsec,得到了质量较高的中长波双色碲镉汞薄膜材料. 相似文献
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对富碲液相外延As掺杂碲镉汞(HgCdTe)材料的研究发现,其电学性能存在着不稳定性,材料霍尔参数的实验数据与均匀材料的理论计算结果也不能很好的吻合.通过采用剥层变温霍尔测量和二次离子质谱(SIMS)测试对材料纵向均匀性进行检测的结果显示,外延材料中的As在高温富汞激活退火过程中具有向材料表面扩散的效应,导致在表面形成了高于主体层浓度1~2个量级的高浓度表面层,并导致了AsTe受主的浓度在HgCdTe薄膜中呈非均匀分布.考虑这一效应并采用双层模型的霍尔参数计算方法后,As掺杂HgCdTe液相外延材料的电学行为得到了较好的解释,并较为准确地获得了退火后材料表面层与主体层的受主浓度及受主能级等电学参数. 相似文献
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文章报道了Si基碲镉汞分子束外延(MBE)的最新研究进展。尝试用晶向偏角降低高界面应变能的方法,摸索大失配体系中位错的抑制途径,寻找位错密度与双晶半峰宽的对应关系,基本建立了外延材料晶体质量无损检测评价标准,并对外延工艺进行指导。通过上述研究,15~20μm Si基CdTe复合材料双晶半峰宽最好结果为54arcsec,对应位错密度(EPD)小于2×106/cm2,与相同厚度的GaAs/CdTe(211)双晶水平相当,达到或优于国际最好结果。获得的3 in 10μm Si基HgCdTe材料双晶半峰宽最好结果为51arcsec,目前Si基HgCdTe材料已经初步应用于焦平面中波320×240器件制备。 相似文献
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一、概述最近几年,Rockwell国际科学中心研究一种代用衬底材料,该材料避免了块状、单晶CdTe所存在的缺点,而且不降低在此衬底上生长的外延HgCdTe的质量。这种衬底是由用适当工艺制备的单晶蓝宝石薄片(其直径典型值为2″)、以及其上液相外延生长的碲化镉薄层(10~20μm)构成,该蓝宝石薄片经特殊的初始表面处理。这种技术是一种外延用的CdTe代用物(PACE)技术,适合用各种外延技术生 相似文献
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为了研究液相外延碲镉汞薄膜表面缺陷形成机制,采用光刻工艺结合化学腐蚀方法在碲锌镉衬底表面实现了网格化,研究了碲锌镉近表面富碲沉积相与外延薄膜表面缺陷的关系.结果表明:衬底近表面富碲沉积相会导致碲镉汞薄膜表面孔洞、类针形凹陷坑缺陷以及三角形凹陷坑聚集区;在液相外延过程中,高温碲镉汞熔液与CdZnTe衬底间的回熔作用可以减少与富碲沉积相相关的表面缺陷,薄膜表面缺陷与衬底表面富碲沉积相的匹配度与回熔深度负相关;回熔过程以及富碲沉积相形态、深度影响HgCdTe薄膜表面缺陷形态和分布. 相似文献
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文章报道了采用液相外延方法,在碲锌镉衬底上进行碲锌镉薄膜缓冲层生长的情况,并且采用X光双晶衍射仪、X光形貌仪、红外傅里叶光谱仪、二次离子质谱仪等手段对碲锌镉薄膜进行了表征,碲锌镉薄膜具有较好地组分及均匀性,晶体结构质量也较好。采用碲锌镉缓冲结构生长了碲镉汞液相外延片,其碲锌镉与碲镉汞薄膜界面附近的杂质得到了有效的控制。 相似文献
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P. Lamarre C. Fulk D. D’Orsogna E. Bellotti F. Smith P. LoVecchio M. B. Reine T. Parodos J. Marciniec S. P. Tobin J. Markunas 《Journal of Electronic Materials》2009,38(8):1746-1754
Dislocations are known to influence the electrical and optical properties of long-wavelength infrared (LWIR) HgCdTe detectors
and have been shown to limit the performance of arrays fabricated on heteroepitaxial substrates. To help better understand
dislocations in HgCdTe, a new method for preparing HgCdTe diagnostic epitaxial single-crystal samples by chemically removing
the supporting CdZnTe substrate has been developed. Using this new sample preparation technique, the behavior of misfit and
threading dislocations in HgCdTe epitaxial layers has been investigated by using a defect etch to reveal the dislocations
present in the thin HgCdTe films. In most cases etch pits on the surface of the film are spatially correlated with etch pits
on the bottom of the HgCdTe film. The small displacements of the related etch pits were used to obtain crystallographic information
concerning the paths followed by threading dislocations on allowed slip planes in the HgCdTe crystal. In addition, transmission
electron microscopy (TEM) is used to obtain more specific information regarding the Burgers vector of the dislocation. While
this new sample preparation technique is useful for studying dislocations in HgCdTe epitaxial layers, it can also be used
to study stress from ohmic contacts and passivation layers. The technique can be used for both liquid-phase epitaxy (LPE)-
and molecular-beam epitaxy (MBE)-grown HgCdTe on CdZnTe substrates. 相似文献
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S. M. Johnson J. A. Vigil J. B. James C. A. Cockrum W. H. Konkel M. H. Kalisher R. F. Risser T. Tung W. J. Hamilton W. L. Ahlgren J. M. Myrosznyk 《Journal of Electronic Materials》1993,22(8):835-842
Large-area HgCdTe 480×640 thermal-expansion-matched hybrid focal plane arrays were achieved by substituting metalorganic chemical
vapor deposition (MOCVD)-grown CdZnTe/GaAs/Si alternative substrate in place of bulk CdZnTe substrates for the growth of HgCdTe
p-on-n double-layer heterojunctions by controllably-doped mercury-melt liquid phase epitaxy (LPE). (100) CdZnTe was grown
by MOCVD on GaAs/Si using a vertical-flow high-speed rotating disk reactor which incorporates up to three two-inch diameter
substrates. Layers having specular surface morphology, good crystalline structure, and surface macro defect densities <50
cm−2 are routinely achieved and both the composition uniformity and run-to-run reproducibility were very good. As the composition
of the CdZnTe layers increases, the x-ray full width at half maximum (FWHM) increases; this is a characteristic of CdZnTe
grown by VPE techniques and is apparently associated with phase separation. Despite a broader x-ray FWHM for the fernary CdZnTe,
the FWHM of HgCdTe grown by LPE on these substrates decreases, particularly for [ZnTe] compositions near the lattice matching
condition to HgCdTe. An additional benefit of the ternary CdZnTe is an improved surface morphology of the HgCdTe layers. Using
these silicon-based substrates, we have demonstrated 78K high-performance LWIR HgCdTe 480×640 arrays and find that their performance
is comparable to similar arrays fabricated on bulk CdZnTe substrates for temperatures exceeding approximately 78K. The performance
at lower temperatures is apparently limited by the dislocation density which is typically in the low-mid 106 cm−2 range for these heteroepitaxial materials. 相似文献
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F. T. Smith P. W. Norton P. Lo Vecchio N. Hartle M. Weiler N. H. Karam S. Sivananthan Y. P. Chen 《Journal of Electronic Materials》1995,24(9):1287-1292
The growth of high quality (111)B oriented HgCdTe layers on CdZnTe/GaAs/Si and CdTe/Si substrates by Te-rich slider liquid
phase epitaxy (LPE) is reported. Although the (111) orientation is susceptible to twinning, a reproducible process yielding
twin-free layers with excellent surface morphology has been developed. The electrical properties and dislocation density in
films grown on these substrates are comparable to those measured in HgCdTe layers grown on bulk CdTe substrates using the
same LPE process. This is surprising in view of the large lattice mismatch that exists in these systems. We will report details
of both the substrate and HgCdTe growth processes that are important to obtaining these results. 相似文献
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研究了HgCdTe液相外延薄膜表面两类宏观缺陷的形成原因.研究表明,大部分表面凹陷点(void)缺陷的形成是由衬底的蜡沾污所引入的,而表面凸起点(hill-like)是由衬底边缘脱落的CdZnTe微颗粒造成的,通过控制外延生长前的衬底处理过程,可以抑制这两类缺陷,从而生长出零(宏观)缺陷密度的优质HgCdTe外延薄膜. 相似文献