High-quality formation of multiply stacked SiGe-on-insulator structures by temperature-modulated successive rapid-melting-growth

摘要

Laterally and vertically modulated SiGe-on-insulator (SGOI) structures are essential to integrate functional device-arrays with various energy-band-gaps and/or lattice-constants. We develop the temperature-modulated successive rapid-melting-growth (RMG) method, where Si-concentration dependent RMG processing is combined with non-destructive crystallinity-analysis. First, SGOI is formed by segregation-controlled RMG of SiGe by using Si-substrate as crystalline-seed. Polarized-Raman-scattering measurements non-destructively reveal the lateral-epitaxial-growth of SGOI with graded SiGe-concentration profiles. Second, Ge-on-insulator (GOI) is stacked on SGOI by using SGOI as crystalline-seed, where RMG temperature is selected between the melting-points of Ge and underlying SGOI. This achieves defect-free, multiply-stacked GOI on graded-SGOI structure, which demonstrates 3-dimensionally modulated SiGe-concentration profiles on Si-platform.