Molecular Beam Epitaxy

Molecular Beam Epitaxy (MBE) is a sophisticated deposition technique performed in ultra high vacuum primarily for the growth of GaAs devices as well as other III/V materials, and II/VI materials. High performance electronic, optoelectronic and photonic devices usually involve complex semiconductor heterostructure layers, and must be grown by advanced thin-film growth techniques such as Molecular Beam Epitaxy. In MBE, atoms are delivered to a substrate through an ultra-pure ultra-high vacuum atmosphere. The atmosphere provided by the MBE chamber allows the atoms to arrive on the substrate without colliding with other atoms or molecules, thus keeping the growth free of other contaminants. The heated substrate surface allows the arriving atoms to distribute themselves evenly across the surface forming an almost perfect crystal structure. In MBE the substrate is placed in an UHV chamber with direct line of sight to several elemental species each of which is in an evaporation furnace commonly referred to as an effusion cell. Through use of shutters and precise control of the effusion cell temperatures almost any material composition and doping can be achieved. Further, the composition may be controlled with a resolution of virtually one atomic layer.
Our system is a modular GEN II solid source MBE machine, a system specially designed for high quality growth of III-V materials. Eight different sources can be used to grow AlAs, InAs, GaAs and any terniary compound (AlGaAs, InGaAs, InAlAs) with different doping concentrations. Insitu RHEED measurements are used to monitor surface conditions and growth rate.