Silicon-germanium molecular beam epitaxy system for high-quality nanostructures and devices

Abstract

A new molecular beam epitaxy system for high-quality silicon (Si) and germanium (Ge) heterostructures and industrial production is described. The home-made substrate heater has a water cooling and is equipped with a sample holder with rotation and a manipulator for z-movement. With a special positioning of shutters, the growth can be started after completing the ramp-up phase of the electron beam evaporators. Mass-spectrometer-controlled evaporation combined with a quartz oscillation monitor allows perfect flux control. During evaporation a growth pressure below 1 × 10 −9 mbar is realized. A high-temperature boron effusion cell and a Knudsen-shutter effusion cell with water cooling guarantee a very sharp δ-doping profiles. Physical and electrical analysis of doping layers is presented. Photoluminescence (PL) characterization of SiGe single-quantum wells (SQWs) are performed. PL measurements on locally grown SiGe SQWs in locally grown Si mesas reveal perfect crystal quality and good passivation of the QW side walls at the mesa edge. The investigated pin-diodes with a SiGe SQW in the intrinsic region show good electrical behavior and electroluminescence up to room temperature.