Low temperature characterization of modulation doped SiGe grown on bonded silicon-on-insulator

Abstract

Modulation doped pseudomorphic Si0.87Ge0.13 strained quantum wells were grown on bonded silicon-on-insulator (SOI) substrates. Comparison with similar structures grown on bulk Si(100) wafers shows that the SOI material has higher mobility at low temperatures with a maximum value of 16 810 cm 2/V s for 2.05×1011 cm−2 carries at 298 mK. Effective masses obtained from the temperature dependence of Shubnikov–de Haas oscillations have a value of (0.27±0.02) m0 compared to (0.23±0.02) m0 for quantum wells on Si(100) while the cyclotron resonance effective masses obtained at higher magnetic fields without consideration for nonparabolicity effects have values between 0.25 and 0.29 m0. Ratios of the transport and quantum lifetimes, τ/τq=2.13±0.10, were obtained for the SOI material that are, we believe, the highest reported for any pseudomorphic SiGe modulation doped structure and demonstrates that there is less interface roughness or charge scattering in the SOI material than in metal–oxide–semiconductor field effect transistors or other pseudomorphic SiGe modulation doped quantum wells.