Coupling Multifunctional Oxides to Semiconductors

技术说明：材料科学中的一个基本方法涉及制造在异质结构中耦合特性的新材料。用于逻辑器件的晶体管使用半导体中的电荷传输来处理信息。 现在有替代方案使用电子自旋来处理信息，既可以降低晶体管的功耗，又可以增加晶体管的功能（如存储器）。 目前，硅和锗被广泛用作沟道材料，因为它们很好地传输电荷，并且这些半导体也非常有效地传输自旋。这个计画的重点是透过绝缘氧化层将铁磁氧化物的自旋耦合到锗上。 这种新型材料系统正在开发中，使用分子束外延的原子层合成，通过界面的化学和结构修饰来操纵和控制进入锗的自旋隧道。 使用原子层控制，可以操纵界面的关键方面以控制自旋耦合。 这些因素包括化学成分、电极化、应变、原子层终止和能带偏移。 使用原位X射线光电子能谱、同步加速器X射线衍射、X射线吸收光谱和透射电子显微镜的组合表征每层的物理和电子结构。 完全外延设计使我们能够理解一个有前途的自旋基器件平台的结构特性。非技术描述：开发用于计算应用的新电子器件需要新材料。 这些新材料的设计要么需要更少的功率，要么在微处理器中提供额外的功能。 该项目的策略是使用电子的自旋作为信息位，而不是像目前这样使用电荷。 该项目合成了新材料，通过一次一个原子层地将薄膜堆叠在一起来操纵电子自旋。原子的位置是用国家实验室的X射线设备确定的。 作为这项工作的一部分，学生和年轻技术人员将接受最先进的半导体技术培训，为他们在半导体行业的职业生涯做好准备。

Technical Description: A fundamental approach in materials science involves the fabrication of new materials that couple properties in heterogeneous structures. Transistors for logic devices use the transport of charge in a semiconductor to process information. There are now alternate proposals to use the electron spin to process information, both to reduce power consumption of and add functionality (such as memory) to the transistor. Currently silicon and germanium are widely used as a channel material because they transport charge well, and these semiconductors also transport spin very efficiently. This project focuses on coupling spin from a ferromagnetic oxide to germanium through an insulating oxide barrier. This novel materials system is being developed using atomic layer synthesis by molecular beam epitaxy to manipulate and control spin tunneling into germanium through chemical and structural modifications of the interfaces. Using atomic layer control, key aspects of the interfaces can be manipulated to control spin coupling. These include chemical composition, electric polarization, strain, atomic layer termination, and band offset. Both the physical and electronic structures of each layer are characterized using a combination of in- situ x-ray photoemission spectroscopy, synchrotron x-ray diffraction, x-ray absorption spectroscopy, and transmission electron microscopy. The fully epitaxial design enables the understanding of structural properties governing the function of a promising spin-based device platform.Non-technical Description: New materials are required to develop new electronic devices for computing applications. These new materials are designed to either require less power or offer additional function in microprocessors. The strategy of the project is to use the spin of an electron as a bit of information rather than charge, as is currently done. The project synthesizes new materials that manipulate electron spin by stacking thin films together one atomic layer at a time. The positions of the atoms are determined using x-ray facilities at the National Laboratories. As part of this work, students and young technicians will be trained in state of the art semiconductor technology, preparing them for careers in the semiconductor industries.