You are here: Home / UCL MBE group / Research Facilities / Veeco GEN 930 Group IV MBE

Veeco GEN 930 Group IV MBE

The Veeco GEN 930 Group IV MBE system has been installed in December 2016. The system has two Silicon sources (effusion and e-beam), Germanium, Tin, Boron (doping) and Antimony (doping) cells. The system has been shipped to UCL in Oct 2015.

chamber2.jpg

The Veeco Gen930 system has three main vacuum chambers: the loadlock chamber, the prep chamber and the growth chamber.  The chambers are separated with ultra-high vacuum (UHV) gate valves to prevent cross-contamination. The system is equipped with an ultra-high vacuum 100cc e-beam evaporator with in-situ deposition monitoring for deposition of  Si. Standard K-cells are used for the evaporation of Ge, Tin and B, while a dual-zone cracking cell is used for Sb. A Reflective High Energy Electron Diffraction (RHEED) system is used to monitor the growth in‑situ. This system is capable of growing Si, Ge, Sn and their alloys, with low-dimensional structure types including quantum dots, nanowires and quantum wells.

The system is capable of growing high-quality silicon epilayers as confirmed with RHEED pattern and AFM measurements.  The RMS roughness of 0.077 nm has been calculated. Such high quality silicon growth is essential for development of high-performance group-IV based devices.

      

The system have also been used to successfully grow Ge epilayers directly on Si wafers. A 250-nm-thick buffer layer grown using two-step growth method has an RMS roughness of approximately 0.1 nm. 

  

Quantum structures like Ge/Si superlattices have been grown using this MBE system. An XRD measurement of a superlattice consisting of ten periods of 20 nm of Si and 2 monolayers of Ge show multiple periodic peaks corresponding to reflections off the Ge/Si interfaces in the superlattice. This indicates that the lattice is of high quality, layers thicknesses are consistent and the interfaces are sharp.