Strained Si n-channel metal–oxide–semiconductor transistor on relaxed Si1−xGex formed by ion implantation of Ge

Ge implantation followed by high-temperature solid phase epitaxy was used to form a relaxed substrate, eliminating need for the growth of relaxed ${\mathrm{Si}}_{\text{1−x}}{\mathrm{Ge}}_x$ layers. Upon this film, a 2000 Å buffer layer of ${\mathrm{Si}}_{\mathrm{0.85}}{\mathrm{Ge}}_{\mathrm{0.15}}$ followed by a 200 Å strained Si layer was grown by ultrahigh-vacuum chemical vapor deposition. For comparison, unstrained Si epitaxial films and a 2000 Å thick film of ${\mathrm{Si}}_{\mathrm{0.85}}{\mathrm{Ge}}_{\mathrm{0.15}}$ (on unimplanted Si) followed by 200 Å of Si were used. n-channel metal–oxide–semiconductor transistors were fabricated and their dc characteristics were examined. Strained Si devices show a 17.5% higher peak linear ${\mu }_{\mathrm{FE}}$ than control devices as a result of higher electron mobility in the strained Si channel. This work demonstrates a simple method for the formation of strained Si layers.