The LCS manages equipment for thin film deposition, mainly dedicated for the growth of III-V semiconductor heterostructures. Unlike the SPM instruments, the machines are not open to external users. Never the less, we are happy to provide samples to external demand, either inside scientific collaborations or as service.
III-V Molecular beam epitaxy system
Since August 2015, the LCS runs a 2″ III-V semiconductor epitaxy chamber. The machine main chamber was constructed by Dr. Karl Eberl MBE Komponenten GmbH and existing components were integrated into the system. It currently consists of an ultra-high vacuum process chamber (base pressure ca. 5.0×10-11 mbar) with four effusion cells (Ga, Al, In, As) and two doping cells (Si,Be). Furthermore, a preparation chamber to carry out hydrogen cleaning is installed. The MBE system is automated with EpiSoft allowing to grow complex heterostructures, e.g. superlattices. RHEED images can be captured with iRHEED. The system was build with financial support of SisNANO, FAPESP and CNPq.
Structural quality of samples
A series of test samples has been grown to demonstrate the structural quality of the machine. We are able to provide high quality GaAs, InGaAs/GaAs and AlGaAs/GaAs heterostructures as well as self-assembled InAs islands.
We grown a first set of standard samples to characterize the optical quality of the epitaxial structures. Photoluminescence was carried out by Fernando Iikawa of the University of Campinas. The obtained spectra indicate a good optical quality of the samples with a low carbon background doping. The InAs island growth has to be further optimized, but the structures are optical active and of good quality.
Beside the members of the LCS, especially Saimon Filipe Covre, Evandro Lanzoni and Ailton Garcia Jr., we like to thank Prof. Dr. S. O. Ferreira, Prof. Dr. F. Iikawa and Prof. Dra. M. Cotta for the help during the setup. We are also grateful to the LNLS workshop and vacuum group as well as the CNPEM maintenance group for there help and contributions during installation of the MBE lab.
See the birth of the machine:
We inherited a Cambridge Atomic layer deposition system. The system was intended to be used for in-situ growth on a beamline. Currently, we prepare the system to be opened as a user growth facility as well as defining internal projects for it. It is used to grow high quality dielectric material like TiO2 and Al2O3 for device application. For obtaining samples from the system, please contact us via e-mail.