High Resolution RHEED applied to the growth of epitaxial oxide layers

Reflection High-Energy Electron Diffraction (RHEED) has established itself as the dominant in-situ characterization tool for the growth of epitaxial layers at moderate and low pressures. This is mainly due to its technological simplicity (an electron beam generated by an emitter impinges on the substrate at low angle, the resulting diffraction pattern is made visible by a phosphorous screen at the opposite side). In addition, RHEED has a very high surface sensitivity due to its strong interaction with the topmost layer(s) of the crystal, and does not interfere with growth equipment as it does not occupy the solid angle in front of the substrate. In my presentation, I will give an introduction to the method, with an emphasis on its practical application in crystal growth. I will then discuss advanced measurement and analysis modes that significantly increase the analytical resolution, such as azimuthal scans combining RHEED with substrate rotation, or new real-time fitting algorithms for growth rate determination. These are particularly useful to determine integer layer coverages of grown layers, enabling the precise manufacturing of thin epitaxial oxide layers with flat interfaces.