Study On Materials And Processes Of Strained Si MOSFETs

Strained Si is emerging as a powerful technique which contains material, structure and device. In this work, both biaxial strained Si materials and device processes were studied,including high quality materials growth with different structures and device processes development.With epitaxial process optimization, SiGe relaxed virtual substrates and strained Si layer were fabricated with different Ge mole fraction and then defect, roughness and strain were studied.We studied strain relaxation of pseudomorphic Si_1-xGe_x layers on Si (100) combined with Ar implantation, thermal annealing and using of coherent strained Si.We also investigated Ge concentration behavior during SiGe oxidation process. Nanometer Ge-rich layer was formed after wet oxidation. More flat surface was observed using dry oxidation compared to wet oxidation process. Ultra thin relaxed SiGe virtual substrates were obtained by SiGe regrown after SiGe oxidation.We developed two isolation module, isolation with field oxide deposition and STI process. Finally both n-channel and p-channel strained Si devices were realized within the same substrate and the performance enhancement were analyzed varied with electron field, temperature and gate length contrast to Si control devices.