Germanium for next generation photonic and microelectronic devices

随着持续的指数增长，全球互联网流量预计到2020年将达到2.3 zettabytes（2.3x270）[2016 Cisco]。然而，主流的短距离通信和片上互连一直由金属线主导，其速度慢得多，能效低，并且难以扩展尺寸。经由硅（Si）光子学的光学互连已被广泛认为是克服这一瓶颈的潜在解决方案。锗（Ge）作为与Si最相容的半导体，已经成为Si光子学的基础和使能材料。Ge已广泛用于光电探测器和调制器，提供> 50 Gbps的数据速率[2015 Chen，2016 Srinivasan]。对于Si兼容激光器，Ge可用作1）激光材料（如InGaAs和AlGaAs）与Si之间的过渡层[2012 Lee，2016 B Lin，2016 Liu，2016 Nakao]，因为它与它们的晶格失配小，易于与Si集成，2）由于带隙工程的激光材料[2010 Liu，2012 C-A]。在微电子方面，Ge已广泛用于SiGe异质结双极晶体管（HBT），用于无线通信。 我们提出了以下主题的锗在硅光子学和微电子学。 1.高度期望在Si上具有低缺陷密度Ge膜以用作III-V和Si过渡层。高宽比捕获技术（ART）可以生产高质量的锗。然而，它需要额外的制造步骤，并且在热传导方面较差。低/高温（LT/HT）生长方法在这两个方面优于ART。然而，Ge质量并不好。砷掺杂已被证明可以大大提高Ge质量[2016 Lee]，而其他掺杂剂的影响尚未研究。我们建议研究掺杂对Ge质量的影响，使用LT/HT方法在Si上生长高质量Ge薄膜。 2.我们建议通过器件建模和模拟来研究锗硅激光器的潜力和优化。 3.随着HBT基极层中Ge浓度的提高，Si-Ge互扩散问题日益突出。我们建议研究PNP型HBT中的互扩散行为，特别是磷和碳的影响，以及这些影响的建模，以实现更快，更节能的无线通信系统。 拟议的研究将在Si平台上实现光电集成电路（OEIC），例如单芯片光收发器，它提供了在几秒钟内下载电影的能力，并且比目前使用外部激光器的技术便宜得多。研究成果可以导致光纤通信更深入的渗透，更快的无线通信和当前信息技术硬件行业的重大进步。我们确实相信，拟议的研究是在研究前沿，将有利于加拿大作为世界领先的光通信和信息技术大大。

With sustained exponential growth, global internet traffic is expected to reach 2.3 zettabytes (2.3x270) by 2020 [2016 Cisco]. However, mainstream short-reach communications and on-chip interconnects have been dominated by metal wires, which are much slower, less energy efficient and hard to scale in size. Optical interconnections via silicon (Si) photonics have been widely recognized as a potential solution to overcome this bottleneck. Germanium (Ge) as the most Si-compatible semiconductor has been the underlying and enabling material for Si photonics. Ge has been widely used in photodetectors and modulators providing a data rate of > 50 Gbps [2015 Chen, 2016 Srinivasan]. For Si-compatible lasers, Ge can be used as 1) transition layers between lasing materials such as InGaAs and AlGaAs and Si [2012 Lee, 2016B Lin, 2016 Liu, 2016 Nakao] due to its small lattice mismatch to them and the ease of integration with Si and 2) a lasing material thanks to bandgap engineering [2010 Liu, 2012 C-A]. On the microelectronics side, Ge has been widely used in SiGe heterojunction bipolar transistors (HBTs) for applications in wireless communications. We propose the following topics on Ge in Si photonics and microelectronics. 1. It is highly desired to have low defect density Ge films on Si to serve as III-V and Si transition layers. Aspect ratio trapping technology (ART) can produce high quality Ge. However, it needs additional fabrication steps and is inferior in thermal conduction. A low/high temperature (LT/HT) growth method is advantageous over ART in these two aspects. However, the Ge quality is not as good. Arsenic doping has been shown to greatly improve Ge quality [2016 Lee], while impacts from other dopants have not studied. We propose to study doping impacts on Ge quality using LT/HT method for high quality Ge film growth on Si. 2. We propose to study the potential and the optimizations of Ge-on-Si lasers by device modeling and simulations. 3. As higher concentration of Ge is used in HBT base layer, Si-Ge interdiffusion is becoming more problematic. We propose to study the interdiffusion behavior in PNP type HBTs, especially the impacts from phosphorus and carbon and the modeling of these impacts for faster and more energy efficient wireless communication systems. The proposed research will enable optoelectronic integrated circuit (OEIC) on Si platforms such as a single-chip optical transceiver, which provides the ability to download movies in seconds and are much cheaper and smaller than the current technology with external lasers. The research outcomes can lead to deeper penetration of optical fiber communications, faster wireless communications and significant advancements in the current information technology hardware industry. We truly believe that the research proposed is at the research frontier and will benefit Canada as a world leader in optical communications and information technology greatly.