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 concern ing measures to obtain good quality of grown films. Good stability, re producibility and uniformity of deposition rates (Si and Ge) and dopin g concentrations (Sb and B) have been obtained for growth on a 4 inch Si wafer with sample rotation using a mass-spectrometry controlled e-b eam evaporation system, and home-made doping sources, respectively. Th e quality of grown undoped and modulation doped Si and SiGe layered st ructures were evaluated using high-resolution XRD, XTEM, SIMS, Hall, a nd PL measurements. Intense and sharp excitonic PL transitions and hig h carrier mobility obtained from the grown Si/SiGe heterostructures an d quantum wells grown at a wide substrate temperature range (320-650 d egrees C) indicate high crystalline quality of grown films. Finally, t est HBT structures with a thin SiGe base have been made. Good de chara cteristics and frequency performance were obtained.