Nanoscale characterisation of nitride semiconductor thin films using EBSD, ECCI, CL and EBIC.

使用 EBSD、ECCI、CL 和 EBIC 对氮化物半导体薄膜进行纳米级表征。

• 批准号: EP/J015792/1
• 负责人: Carol Trager-Cowan
• 金额: $ 61.36万
• 依托单位: University of Strathclyde
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FJ015792%2F1
• 关键词: Nanoscale; characterisation; nitride; semiconductor; thin

The aim of this project is to produce a step change in the performance of the scanning electron microscopy techniques of electron backscatter diffraction (EBSD), and electron channelling contrast imaging (ECCI), and exploit these relatively new techniques together with cathodoluminescence imaging (CL) and electron beam induced current (EBIC) for the characterisation and hence the improvement of nitride semiconductor thin films. Such materials are used in the manufacture of UV/blue laser diodes, UV/visible LEDs and white LEDs. Nitride laser diodes are presently dictating the development of next generation DVDs and developments in printing and colour copying. Present applications of nitride LEDs extend from street lighting, to back lighting in mobile phones, to traffic lights. Future use of nitride-based LEDs promises to revolutionise lighting in the home and office. Nitrides are also being developed for the production of high frequency, high power electronic devices.EBSD is an attractive technique with which to interrogate the crystallographic properties of materials because it can provide information on crystal orientation, polytype and strain with a resolution of tens of nanometres. In EBSD an electron beam is incident on a sample which is tilted at an angle of typically 70 degs. The impinging electrons are scattered inelastically through high angles forming a diverging source of electrons that can be diffracted. A simple description for the formation of an electron backscatter diffraction pattern (EBSP) presumes that electrons that satisfy the Bragg condition for a given plane emanate in diffraction cones from both the upper and lower surfaces of that plane. When these cones intersect a phosphor screen Kikuchi lines are observed. An EBSP consists of a large number of overlapping Kikuchi bands and is a 2-D projection of the crystal structure. Rotation of a crystal will produce a rotation of the EBSP; a tilt of a crystal will produce a shift in the EBSP, strain will produce distortion of the EBSP. EBSPs acquired from a mesh of points on a sample will produce a map of tilt, rotations or strain in that sample. In the course of our research we aim to attain much improved levels of sensitivity (less than 1 part in 10,000) to changes in tilt, rotation and strain to obtain detailed high resolution information on the crystallographic texture and strain distribution in nitride semiconductors.ECCI can be used to reveal single crystallographic defects such as dislocations in semiconductor thin films. In ECCI the intensity of electrons backscattered from a suitably oriented sample depends on the relative orientation of planes in a crystal. Changes in crystallographic orientation or changes in lattice constant due to strain are revealed by changes in grey scale of an image constructed by monitoring the intensity of backscattered electrons as an electron beam is scanned over the sample. Defects are imaged due to lattice plane tilting and strain they produce. Our aim is develop the ECCI technique so that it may be used to fully characterise all defects present in our films.We plan to apply these powerful techniques to optimise the quality of nitride semiconductor thin films, including: (i) non-polar and semi-polar nitride thin films, (ii) epitaxially overgrown nitride thin films and nitride thin films grown on native substrates, (iii) high aluminium content nitride thin films (including films grown on silicon), (iv) high indium content nitride thin films, and (v) zinc blende nitride thin films. Such novel nitride semiconductor structures will allow the production of higher power LEDs and extend their wavelength range to the red and infrared. They will also open up new applications for nitride-based devices - solar cells for example.Throughout the project we will also establish with industrial partners the best routes for development and commercialisation of new instrumentation, and nitride thin film growth processes.

本项目的目的是使扫描电子显微镜技术的性能发生阶梯变化，如电子背散射衍射(EBSD)和电子沟道对比成像(ECCI)，并将这些相对较新的技术与阴极发光成像(CL)和电子束感应电流(EBIC)一起用于表征，从而改进氮化物半导体薄膜。这种材料用于制造UV/蓝色激光二极管、UV/可见光LED和白色LED。氮化物激光二极管目前主导着下一代DVD的发展以及印刷和彩色复制的发展。目前氮化物LED的应用范围从街道照明扩展到移动电话的背光照明，再到交通灯。未来氮化物LED的使用有望给家庭和办公室的照明带来革命性的变化。氮化物也被开发用于生产高频、高功率电子器件。EBSD是一种有吸引力的技术，可以用来询问材料的晶体性质，因为它可以提供晶体取向、多型和应变的信息，分辨率可达数十纳米。在EBSD中，电子束入射到通常以70度角倾斜的样品上。入射的电子以非弹性的方式通过高角散射，形成一个发散的电子源，可以绕射。对于电子背向散射衍射图(EBSP)的形成，一种简单的描述是假定满足给定平面的布拉格条件的电子在该平面的上下表面的衍射锥中发射。当这些锥体与荧光屏相交时，可以观察到菊池线条。EBSP由大量重叠的菊池带组成，是晶体结构的二维投影。晶体的旋转会产生EBSP的旋转；晶体的倾斜会产生EBSP的位移，应变会产生EBSP的变形。从样本上的点网格中获取的EBSP将在该样本中生成倾斜、旋转或应变的地图。在我们的研究过程中，我们的目标是大大提高对倾斜、旋转和应变变化的敏感度(不到万分之一)，以获得关于氮化物半导体中晶体织构和应变分布的详细高分辨率信息。ECCI可用于揭示半导体薄膜中的单晶学缺陷，如位错。在ECCI中，从适当取向的样品反向散射的电子的强度取决于晶体中平面的相对取向。当电子束在样品上扫描时，通过监测背散射电子的强度构建的图像的灰度变化，可以揭示晶体取向的变化或晶格常数因应变而发生的变化。缺陷是由于晶格面倾斜及其产生的应变而成像的。我们计划应用这些强大的技术来优化氮化物半导体薄膜的质量，包括：(I)非极性和半极性氮化物薄膜，(Ii)外延生长的氮化物薄膜和在天然衬底上生长的氮化物薄膜，(Iii)高铝含量氮化物薄膜(包括在硅上生长的薄膜)，(Iv)高铟含量氮化物薄膜，和(V)闪锌矿氮化物薄膜。这种新颖的氮化物半导体结构将允许生产更高功率的LED，并将其波长范围扩展到红色和红外。他们还将为基于氮化物的设备开辟新的应用领域，例如太阳能电池。通过该项目，我们还将与工业合作伙伴建立新仪器的开发和商业化的最佳路线，以及氮化物薄膜生长工艺。

项目成果

Spatial clustering of defect luminescence centers in Si-doped low resistivity Al0.82Ga0.18N

• DOI: 10.1063/1.4928667
• 发表时间: 2015-08-17
• 期刊: APPLIED PHYSICS LETTERS
• 影响因子: 4
• 作者: Kusch, Gunnar;Nouf-Allehiani, M.;Martin, Robert W.
• 通讯作者: Martin, Robert W.

Cathodoluminescence Hyperspectral Imaging of Nitride Semiconductors: Introducing New Variables

氮化物半导体的阴极发光高光谱成像：引入新变量

• DOI: 10.1017/s1431927614006254
• 发表时间: 2014
• 期刊: Microscopy and Microanalysis
• 影响因子: 2.8
• 作者: Edwards P

Design and fabrication of enhanced lateral growth for dislocation reduction in GaN using nanodashes

• DOI: 10.1016/j.jcrysgro.2017.02.047
• 发表时间: 2017-05
• 期刊: Journal of Crystal Growth
• 影响因子: 1.8
• 作者: E. D. Boulbar;J. Priesol;M. Nouf-Allehiani;G. Naresh-Kumar;S. Fox;C. Trager-Cowan;A. Šatka;D. A

Electron channelling contrast imaging for III-nitride thin film structures

• DOI: 10.1016/j.mssp.2016.02.007
• 发表时间: 2016-06-01
• 期刊: MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
• 影响因子: 4.1
• 作者: Naresh-Kumar, G.;Thomson, D.;Trager-Cowan, C.
• 通讯作者: Trager-Cowan, C.

Influence of substrate miscut angle on surface morphology and luminescence properties of AlGaN

• DOI: 10.1063/1.4867165
• 发表时间: 2014-03-03
• 期刊: APPLIED PHYSICS LETTERS
• 影响因子: 4
• 作者: Kusch, Gunnar;Li, Haoning;Martin, Robert W.
• 通讯作者: Martin, Robert W.