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Instrument to identify defects and impurities in wide band gap semiconductors via excited states

通过激发态识别宽带隙半导体中的缺陷和杂质的仪器

基本信息

批准号：
EP/P015581/1
负责人：
Matthew Halsall
金额：
$ 100.79万
依托单位：
University of Manchester
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FP015581%2F1
关键词：
Instrument identify defects impurities wide

项目摘要

The researchers propose to develop a new instrument to measure the electrical properties of defects in wide band gap semiconductors. The most important wide gap materials at the present time are compounds made from metals from group III of the periodic table and nitrogen such as GaN and InGaN. These are referred to as III-N materials. They are used to make low energy lighting, LASERs and efficient RF and high power transistors. Today's generation of these devices does not function as well as would seem possible from the properties of the materials and at the present time functionality and performance is limited. LEDs and LASERs (other than blue) are less efficient at generating light than expected and in the case of the transistors several aspects of performance are less than desirable. This is due, at least in part, to the presence of defects in the component materials and devices. These defects are difficult to identify using existing techniques. They may be due to impurities or imperfections in the crystal lattice resulting from the crystal growth or introduced during the device manufacturing process. The research group at Manchester have over thirty years of experience in solving defect problems in other materials such as GaAs and Si. Devices made from these materials have revolutionized society through mass produced electronics and communication technologies. The ability to measure, understand and control defects, particularly electrically active defects, has played a major role in this immense technological achievement and instruments devised, developed and licensed from Manchester have played a role in this. In the case of the III-N materials detecting defects and quantifying their properties is much more difficult and no technique exists at the moment which can look at all the band gap and quantify the recombination paths and trapping centres which degrade III-N devices.The defining feature of the new instrument is that it uses sub-band gap light from tunable semiconductor LASERs to create excited states of the defects. Carriers are then thermally ionised to the semiconductor bands from the excited states. Because the optical excitation stimulates a bound to bound transition, a fine line spectrum can be obtained which is a fingerprint of the defect species and its location in the lattice. In the case of many defects being present, the emission rates will be separated using our existing Laplace DLTS processing. Recombination and trapping parameters can be obtained using the methodologies developed for variants of DLTS and LDLTS. One of our project partners (Santa Barbara University in California) will undertake theoretical studies aimed at associating the excited state spectra with chemical species and/or the structure of the defect with a view to generalized identification rather than using correlation with previously obtained spectra.The instrument development is complementary to the EPSRC contracts currently in progress at many UK universities for the development of III-N materials and devices. In the initial phase of the instrument development, collaborations with consortia led by Cambridge and Glasgow for testing materials and power devices have been negotiated. This will be broadened to embrace other groups as the project progresses. Industrial interest in the project has resulted in strong support from five companies in the field of manufacture of III-N materials, LEDs, GaN power devices and instrumentation. Four of these are UK based. The potential benefits to society of a successful completion of this contract are enormous in facilitating greater improvements in domestic lighting and enabling new applications of the III-N materials to be developed for example in efficient short wavelength UV GaN LEDs. These could be used in cheap low maintenance drinking water sterilization, a pressing concern in the developing world.

研究人员建议开发一种新的仪器来测量宽带隙半导体中缺陷的电学特性。目前最重要的宽禁带材料是由周期表第III族金属和氮制成的化合物，如GaN和InGaN。这些被称为III-N材料。它们用于制造低能耗照明、激光器和高效RF和高功率晶体管。今天这一代的这些设备的功能并不像从材料的性质看起来可能的那样好，并且目前功能和性能是有限的。LED和激光器（除蓝色之外）在产生光方面的效率低于预期，并且在晶体管的情况下，性能的几个方面低于期望。这至少部分是由于组件材料和设备中存在缺陷。这些缺陷难以使用现有技术来识别。它们可能是由于晶体生长或器件制造过程中引入的晶格中的杂质或缺陷造成的。曼彻斯特的研究小组在解决其他材料（如GaAs和Si）的缺陷问题方面拥有超过30年的经验。由这些材料制成的设备通过大规模生产的电子和通信技术彻底改变了社会。测量、理解和控制缺陷的能力，特别是电活性缺陷，在这一巨大的技术成就中发挥了重要作用，曼彻斯特设计、开发和许可的仪器在这方面发挥了作用。在III-N材料的情况下，检测缺陷并量化其特性要困难得多，并且目前还不存在可以查看所有带隙并量化使III-N器件退化的复合路径和捕获中心的技术。新仪器的定义特征是，它使用来自可调谐半导体激光器的子带隙光来创建缺陷的激发态。然后载流子从激发态热电离到半导体能带。因为光激发激发束缚到束缚跃迁，所以可以获得精细线光谱，其是缺陷种类及其在晶格中的位置的指纹。在存在许多缺陷的情况下，将使用我们现有的拉普拉斯DLTS处理来分离发射率。使用为DLTS和LDLTS变体开发的方法可以获得纯化和捕获参数。我们的项目合作伙伴之一（加州的圣巴巴拉大学）将进行理论研究，旨在将激发态光谱与化学物质和/或缺陷结构联系起来，以便进行广义识别，而不是使用与先前获得的光谱的相关性。仪器开发是对英国许多大学目前正在进行的EPSRC合同的补充，用于开发III-N材料和器件。在仪器开发的初始阶段，与由剑桥和格拉斯哥领导的联盟就测试材料和动力装置进行了谈判。随着项目的进展，这一范围将扩大到包括其他群体。工业界对该项目的兴趣得到了III-N材料、LED、GaN功率器件和仪器仪表制造领域五家公司的大力支持。其中四个是英国的。该合同的成功完成对社会的潜在利益是巨大的，有利于促进家庭照明的更大改进，并使III-N材料的新应用得以开发，例如在高效的短波长紫外GaN LED中。这些可以用于廉价的低维护饮用水消毒，这是发展中国家迫切关注的问题。

项目成果

期刊论文数量（7）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

GaN surface sputter damage investigated using deep level transient spectroscopy

DOI：
10.1016/j.mssp.2020.105654
发表时间：
2021-05
期刊：
Materials Science in Semiconductor Processing
影响因子：
4.1
作者：
Xiaoyan Tang;S. Hammersley;V. Markevich;I. Hawkins;I. Crowe;T. Martin;Tony Peaker;M. Halsall
通讯作者：
Xiaoyan Tang;S. Hammersley;V. Markevich;I. Hawkins;I. Crowe;T. Martin;Tony Peaker;M. Halsall

Towards substrate engineering of graphene-silicon Schottky diode photodetectors.

DOI：
10.1039/c7nr09591k
发表时间：
2017-06
期刊：
Nanoscale
影响因子：
6.7
作者：
H. Selvi;N. Unsuree;E. Whittaker;M. Halsall;E. Hill;A. Thomas;P. Parkinson;T. Echtermeyer
通讯作者：
H. Selvi;N. Unsuree;E. Whittaker;M. Halsall;E. Hill;A. Thomas;P. Parkinson;T. Echtermeyer

Photomodulated Reflectivity Measurement of Free-Carrier Dynamics in InGaN/GaN Quantum Wells