What are the differences between MOCVD and MBE?
In essence, the various techniques are the same and involve the controlled deposition of tiny particles onto the surface in question as depicted in the above diagram. There are several methods that have evolved over the years: a) Molecular Beam Epitaxy (MBE) in which the particles are atoms or molecules e.g. As2 or Si evaporated from the solid under ultra-high vacuum conditions. b) Metal Organic Vapour Phase Epitaxy (MOVPE, also known as Metal Organic Chemical Vapour Deposition MOCVD) where the particles are organic molecules containing a metal atom. The molecule ‘cracks’ on the surface to leave the metal atom behind, the organic part being volatile moves away from the surface. c) Ion Beam Sputtering involves nano / micron size globules of the element being formed and directed at the surface under high vacuum condition. Irrespective of the deposition technique, it is possible to monitor the development of the thin film as it is being deposited using optical techniques.
