Metal Organic Vapor Phase Epitaxy
Two different MOVPE growth kits are installed in the MOVPE lab. Both were manufactured by the AIXTRON AG, Aachen. Both reactors have an enormous flexibility with respect to the number of different source chemicals useable and the carrier gases and their mixtures. The first is a model AIX 200 (year of manufacture 1989) with two reactors on top of each other heated by an infrared heating system and equipped with substrate rotation used for the deposition of conventional III/V materials. In the upper reactor, InP/InGaAs-layers for high mobility electron gas structures are produced, in the lower one dimensional whisker structures are deposited and their conformal overgrowth is developed.
The other MOVPE system is a model AIX 200/4 RFS (year of manufacture 1998, rebuilt for nitride growth 2002), with two reactors side by side which are heated with an RF heating system and are equipped with substrate rotation. This system is used for III nitride growth. A separation plate is inserted in the gas inlet of the reactor with which the ammonia and the group III sources are injected separately into the reactor. The special feature of this system is the possibility to switch between two different inlet configurations: the conventional in which ammonia is injected closer to the substrate surface and the inverted - here the ammonia is injected closer to the reactor ceiling. One reactor is reserved for the deposition of GaN based HEMT- and 2DEG-structures as well as for AlN-layers, the second is reserved for the development of III nitride:Cr growth. Both reactors are equipped with in situ analysis: an EpiR-TT-DA system, LayTec with a wavelength regime from 250 - 825 nm and two optical sensors.