FM - solid state physics and physics of materials

FM.MBE - Molecular Beam Epitaxy and Growth Control by Electron Diffraction (RHEED)

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High purity single crystal semiconductor compounds can be grown by Molecular Beam Epitaxy (MBE) with high control under Ultra High Vacuum (UHV) conditions. In this way complex heterostructures can be deposited with high precision and with atomic sharp interfaces on a heated substrate surface. The growth process critically depends on the substrate temperature as well as on the material fluxes from the sources and on the surface quality. Therefore all the above parameters have to be precisely controlled during epitaxy.

In this Lab a Gallium Nitride (GaN) layer is deposited on a GaN quasi-substrate in a MBE system. The GaN growth is analysed depending on the impinging Ga flux by means of Reflection High Energy Electron Diffraction (RHEED). Under Ga-rich conditions the stable GaN(0001) surface is terminated by a Ga bilayer. Accordingly, the best growth conditions for GaN under Ga-rich supply should maintain the Ga-bilayer at the surface and this will be setup and controlled by RHEED. After the growth of a GaN layer an AlN layer will be deposited on top.

IV. Physikalisches Institut, B04.103