A silicon molecular beam epitaxy system dedicated to device-oriented material research

Design, performance test, doping capability and grown material quality of a Balzers UMS 630 Si MBE system are reported, particularly concerning measures to obtain good quality of grown films. Good stability, reproducibility and uniformity of deposition rates (Si and Ge) and doping concentrations (Sb and B) have been obtained for growth on a 4 inch Si wafer with sample rotation using a mass-spectrometry controlled e-beam evaporation system, and home-made doping sources, respectively. The quality of grown undoped and modulation doped Si and SiGe layered structures were evaluated using high-resolution XRD, XTEM, SIMS, Hall, and PL measurements. Intense and sharp excitonic PL transitions and high carrier mobility obtained from the grown Si/SiGe heterostructures and quantum wells grown at a wide substrate temperature range (320-650 degrees C) indicate high crystalline quality of grown films. Finally, test HBT structures with a thin SiGe base have been made. Good de characteristics and frequency performance were obtained.