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Applications of Epitaxial lift off technology for II-VI semiconductors

II-VI族半导体外延剥离技术的应用

基本信息

批准号：
EP/L025396/1
负责人：
Kevin Prior
金额：
$ 49.44万
依托单位：
Heriot-Watt University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2014
资助国家：
英国
起止时间：
2014 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FL025396%2F1
关键词：
Applications Epitaxial lift off technology

项目摘要

Semiconductor structures containing different materials are grown as thin film multilayers by techniques such as molecular beam epitaxy (MBE). MBE produces layers with excellent control of thickness but is limited to total thicknesses of just a few microns. In addition, growth takes place on a substrate, which is a highly crystalline template of a material such as gallium arsenide. After growth, the thin film layer remains bonded to the substrate.However, if one of the layers deposited is a so-called sacrificial layer soluble in a solvent (such as a weak acid) then all the layers deposited on top of it can be removed from the substrate. This process is called epitaxial lift off (ELO) and is advantageous in applications where the substrate is either not required or even hinders the operation of the device. Often using ELO means that the substrate can be recycled, which can reduce operating costs. An additional use for ELO is that the layers can be assembled into complex structures with many different types of materials. ELO layers can be transferred to intermediate flexible plastic substrates and patterned before assembly, so very complex structures can be produced.II-VI semiconductors are materials with a number of very useful properties, for example bandgaps ranging from 0 to 5eV. Other II-VI semiconductors have useful magnetic properties, for example some (e.g. CrS) are ferromagnets and others (e.g. MnS) are antiferromagnets. At Heriot-Watt University (HWU), we developed ELO for II-VI compounds using MgS sacrificial layers. The original method could only be used on small sample sizes (3mm square) but demonstrated many useful applications. Within the last few months we have developed a number of breakthroughs in II-VI ELO which show it has much more potential. In particular, we can remove pieces several square cm in size using a flexible plastic carrier. An additional very useful property is that when two ELO layers touch they will combine together, or stack, with the adhesion between layers so strong that they cannot be separated without breaking them.This proposal aims to develop this technology in 3 ways. First, we will show that ELO is easily extended to whole semiconductor wafers, and ELO layers can be transferred on flexible plastic carriers and patterned into small components. The components can be transferred again (stamped) to a final destination. All of this will be done with high (~100%) yield.Second, we will demonstrate the advantages of II-VI ELO by assembling 5 different demonstrator devices requested by our colleagues at HWU. We will supply these for evaluation as part of their own on-going research programmes. The devices include two types of sensors (temperature, and electric or magnetic fields), an optical diode, which only allows light propagation in one direction, a frequency doubler and a photonic bandgap structure. These structures are very difficult to produce by normal thin film growth techniques, but are easily produced by stacking ELO layers.The final strand of the programme develops the potential of ELO in different ways. The ability to move electrons or holes between ELO and adjacent layers would increase the number of applications: for example allowing us in future to develop photovoltaics or detectors. We will measure the electrical transport properties across ELO junctions between ZnSe and different materials and if possible modify them with different surface treatments.One surface treatment developed at HWU protects the II-VI layer surface after growth against contamination. At HWU it has worked for several months. We aim to show that it can be used to transport HWU ELO layers to City College, New York and show that it is possible to combine materials which are not available in the same MBE system and make ELO available to other groups.

包含不同材料的半导体结构通过诸如分子束外延（MBE）的技术生长为薄膜多层。分子束外延生产的层具有良好的厚度控制，但总厚度仅限于几微米。此外，生长发生在衬底上，该衬底是诸如砷化镓的材料的高度结晶的模板。然而，如果沉积的层之一是可溶于溶剂（例如弱酸）的所谓牺牲层，则可以从衬底上去除沉积在其上的所有层。该工艺被称为外延剥离（ELO），并且在不需要衬底或者甚至阻碍器件操作的应用中是有利的。通常使用ELO意味着基板可以回收，这可以降低运营成本。ELO的另一个用途是可以将层组装成具有许多不同类型材料的复杂结构。ELO层可以转移到中间柔性塑料基板上，并在组装之前进行图案化，因此可以生产非常复杂的结构。II-VI族半导体是具有许多非常有用特性的材料，例如带隙范围为0至5eV。其他II-VI族半导体具有有用的磁性，例如一些（例如CrS）是铁磁体，而其他（例如MnS）是反铁磁体。在赫瑞瓦特大学（HWU），我们使用MgS牺牲层开发了II-VI化合物的ELO。最初的方法只能用于小样本（3平方毫米），但证明了许多有用的应用。在过去的几个月里，我们在II-VI ELO方面取得了一些突破，这表明它具有更大的潜力。特别是，我们可以使用灵活的塑料载体去除几平方厘米大小的碎片。另一个非常有用的特性是，当两个ELO层接触时，它们将联合收割机结合在一起或堆叠，层间的粘合力如此之强，以至于它们不能在不破坏它们的情况下分离。首先，我们将表明，ELO很容易扩展到整个半导体晶片，ELO层可以转移到柔性塑料载体和图案化成小组件。组件可以再次转移（盖章）到最终目的地。所有这些都将以高产量（~100%）完成。其次，我们将通过组装HWU同事要求的5种不同的演示设备来展示II-VI ELO的优点。我们将提供这些评估作为他们自己正在进行的研究计划的一部分。这些器件包括两种类型的传感器（温度、电场或磁场）、一个只允许光在一个方向上传播的光学二极管、一个倍频器和一个光子带隙结构。这些结构很难通过普通的薄膜生长技术来生产，但很容易通过堆叠ELO层来生产。该计划的最后一条链以不同的方式开发了ELO的潜力。在ELO和相邻层之间移动电子或空穴的能力将增加应用的数量：例如，允许我们在未来开发光电子器件或探测器。我们将测量ZnSe和不同材料之间的ELO结的电输运特性，如果可能的话，用不同的表面处理对其进行修改。HWU开发的一种表面处理可以保护生长后的II-VI层表面免受污染。在HWU，它已经工作了几个月。我们的目的是表明，它可以用来运输HWU ELO层，纽约城市学院，并表明，它是可能的联合收割机材料，这是不可在同一MBE系统，使ELO提供给其他群体。