MRI: Development of Molecular Beam Expitaxy Apparatus for Growth of Two Dimensional Electron Gas Systems with Mobility of 100,000,000 cm2/Vs

MRI：开发用于生长迁移率达 100,000,000 cm2/Vs 的二维电子气系统的分子束外延装置

• 批准号: 0923369
• 负责人: Loren Pfeiffer
• 金额: $ 180万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0923369&HistoricalAwards=false
• 关键词: MRI; Development; Molecular; Beam; Expitaxy

0923369PfeifferPrinceton UniversityTechnical Abstract:The goal of the project is to construct a new molecular beam epitaxy (MBE) machine specifically designed to produce semiconductor hetero-structures of unprecedented purity and quality. The structures will be designed to yield two-dimensional electron system (2DES) samples having free carrier mobilities in excess of 100,000,000 cm2/Vs at cryogenic temperatures. At the low level of chemical and structural impurities envisioned, the free 2D electrons will interact primarily with each other through the many-body Coulomb interaction. The availability of such samples will enable an unprecedented level of inquiry into a broad range of fundamental questions in many-body phenomena in condensed matter physics. In the past, as the quality of 2D hetero-structures has improved, new physics has been discovered, that has led to two Nobel Prizes. These high quality 2DES are also expected to be important for the next generation of technology. They are crucial, for example, in examining topological approaches in quantum computing.Carrier mobility is a direct indication of semiconductor crystalline quality. Recent experiments have revealed the current record 2D electron mobility of 36,000,000 cm2/Vs is likely limited by residual chemical impurities located within the GaAs conducting channel. These impurities can arise from multiple sources: vacuum out-gassing and breakdown of the furnace parts containing the molten elemental sources in the MBE machine, chemical impurities in the elemental sources themselves, and leaks or out-gassing of the MBE chamber and the substrate heating equipment. In the new machine, improved vacuum pumping and the introduction of a novel vacuum cryopump will substantially reduce the levels of critical impurities. Based on recent results and calculations, we predict the new machine will be able to grow samples with carrier mobilities in excess of 100,000,000 cm2/Vs.Layman?s Abstract:The goal of the proposed project is a new crystal growth machine specifically designed to produce semiconductor crystals of record quality and purity. In present day crystals the free conduction electrons scatter off fixed residual chemical impurities, or off the neighboring conduction electrons. With this new MBE (Molecular Beam Epitaxy) machine we expect to produce crystals with strongly reduced impurity levels, so that the dominant scattering that the free electrons suffer will almost exclusively be from other free electrons. The electrons will be able to easily move about without running into fixed impurities, thus leading to the record ?mobility? in the project title. Such samples will enable an unprecedented level of inquiry into a broad range of fundamental questions in condensed matter physics. In the past, as crystal purity levels have improved, new results were discovered which led to Physics Nobel Prizes in 1985, and 1998. Such near-perfect crystals are also important for long range technological applications ? such as new approaches to computing after the current shrinking of microchips according to ?Moore?s Law? becomes no longer feasible. The MBE machine to be constructed will have record quality of vacuum inside ? fewer impurity molecules will be inside to contaminate the growing semiconductor crystal than in any other crystal growth machine in the world. The work will take place at the Princeton Institute for the Science and Technology of Materials and the Department of Electrical Engineering at Princeton University. About 150 students and researchers across the US will directly benefit from this project.

0923369Pfeiffer普林斯顿大学技术摘要：该项目的目标是建造一台新型分子束外延（MBE）机器，专门用于生产纯度和质量前所未有的半导体异质结构。 该结构将设计用于产生在低温下自由载流子迁移率超过 100,000,000 cm2/Vs 的二维电子系统 (2DES) 样品。 在预期的低水平化学和结构杂质下，自由二维电子将主要通过多体库仑相互作用相互相互作用。 此类样本的可用性将使对凝聚态物理多体现象的广泛基本问题的探究达到前所未有的水平。过去，随着二维异质结构质量的提高，新的物理学被发现，并因此获得了两项诺贝尔奖。 这些高质量 2DES 预计对下一代技术也很重要。 例如，它们对于研究量子计算中的拓扑方法至关重要。载流子迁移率是半导体晶体质量的直接指标。 最近的实验表明，当前记录的 36,000,000 cm2/Vs 二维电子迁移率可能受到位于 GaAs 导电沟道内残留化学杂质的限制。这些杂质可能由多种来源产生：MBE 机器中含有熔融元素源的炉部件的真空排气和故障、元素源本身中的化学杂质以及 MBE 室和基材加热的泄漏或排气设备。 在新机器中，改进的真空泵和新型真空低温泵的引入将大大降低关键杂质的水平。 根据最近的结果和计算，我们预测新机器将能够生长载流子迁移率超过 100,000,000 cm2/Vs 的样品。Layman 摘要：该项目的目标是专门设计用于生产的新型晶体生长机器质量和纯度创纪录的半导体晶体。 在当今的晶体中，自由传导电子从固定的残留化学杂质或邻近的传导电子中散射出来。 通过这种新型 MBE（分子束外延）机器，我们期望生产出杂质水平大大降低的晶体，因此自由电子遭受的主要散射几乎完全来自其他自由电子。 电子将能够轻松移动而不会遇到固定的杂质，从而创造了创纪录的“迁移率”。在项目标题中。 这些样本将使对凝聚态物理学中广泛的基本问题的探究达到前所未有的水平。过去，随着晶体纯度水平的提高，人们发现了新的结果，并于 1985 年和 1998 年获得了诺贝尔物理学奖。这种近乎完美的晶体对于长期技术应用也很重要？例如根据“摩尔定律”当前微芯片尺寸缩小后的新计算方法变得不再可行。 即将建造的 MBE 机器将具有创纪录的内部真空质量？与世界上任何其他晶体生长机相比，内部污染生长的半导体晶体的杂质分子更少。 这项工作将在普林斯顿材料科学技术研究所和普林斯顿大学电气工程系进行。 美国约 150 名学生和研究人员将直接从该项目中受益。