Self-diffusion of the constituent elements in LaAlO3

氧化铝镧（LaAlO 3）在与半导体工业直接相关的基础研究中占据着重要地位：半导体工业领域最具挑战性的任务之一是CMOS结构的不断缩小。为了实现这一目标，需要使用具有高介电常数的新材料。LaAlO 3具有高介电常数和与硅的低晶格失配，是一种非常有前途的栅介质。此外，从基础的角度来看，LaAlO 3也是一种非常有趣的材料：在与SrTiO 3的界面处，形成了二维电子气，这是目前基础研究的主题。这种界面效应形成了新型电子元件（例如氧化物场效应晶体管）的物理基础。考虑到LaAlO 3的这种突出作用，缺乏单晶和薄膜中的实验自扩散数据是特别不利的。如今，材料成分流动性的计算机模拟非常强大-但仍然需要实验参考数据来验证/评估结果。该项目将在尽可能充分表征的实验条件下获得这些参考数据（材料的定义结构和杂质的化学分析）。因此，该项目的主要目标是通过对单晶LaAlO 3和LaAlO 3薄膜中的所有组成元素进行示踪扩散测量，提供LaAlO 3缺失的扩散参考数据。在SrTiO 3/LaAlO 3异质结构的相互扩散的测量将提供实验信息（扩散分布），这将是在这种特殊情况下的阳离子迁移率的耦合建模的基础。此外，阳离子的迁移率和异质结构的微观结构之间的相关性将被示出。这也提供了有关的原子输运的成分LaAlO 3，这已经存在的SrTiO 3，这是至关重要的理解在较高的工艺温度下的异质系统的行为。这种理解不仅在制造中很重要，而且对于预测异质结构的长期稳定性也很重要。

Lanthanum aluminum oxide (LaAlO3) occupies a prominent role in fundamental research directly related to the semiconductor industry: one of the most challenging tasks in the field of semiconductor industry is the continuous downsizing of CMOS structures. To achieve this goal, the use of new materials with high permittivity is required. With a high dielectric constant, and low lattice mismatch with silicon, LaAlO3 is a very promising gate dielectric. In addition, LaAlO3 is also a very interesting material from a fundamental point of view: at the interface with SrTiO3, a two-dimensional electron gas is formed, which is currently the subject of fundamental research. This interface effect forms the physical basis for novel electronic components (e.g. oxide field-effect transistors).Considering this prominent role of LaAlO3, the lack of experimental self-diffusion data in single crystals and thin films is particularly disadvantageous. Computer simulations of the mobility of the constituents of a material are very powerful nowadays - but experimental reference data are still necessary to verify/evaluate the results. Such reference data are to be obtained in this project under experimental conditions that are as well characterized as possible (defined structure of the material and chemical analysis of the impurities).The main goal of this project is therefore to provide the missing diffusion reference data for LaAlO3 by performing tracer diffusion measurements of all constituent elements in single crystalline LaAlO3 and thin LaAlO3 films. The measurement of interdiffusion in the SrTiO3/LaAlO3 heterostructure will supply experimental information (diffusion profiles) which will be the basis for modelling the coupling of the cation mobilities in this special case. Furthermore, a correlation between the mobility of the cations and the microstructure of the heterostructure will be shown. This also provides the relevant information on the atomic transport of the constituents for LaAlO3, which already exists for SrTiO3 and which is crucial for understanding the behaviour of the heterosystem at higher process temperatures. This understanding is not only important in manufacturing but also for predictions on the long-term stability of the heterostructures.