Formation of compressively strained Si/Si1−xCx/Si(100) heterostructures using gas-source molecular beam epitaxy

With an aim to achieve compressively strained Si in which low hole effective mass is expected, investigations on growth of compressively strained Si/Si1−xCx/Si(100) heterostructure were carried out using gas-source molecular beam epitaxy (MBE). It was found that crystalline morphology and lattice strain strongly depends on substrate temperature. The compressively-strained Si with smooth surface was successfully realized at 550 °C. It was found that dislocation is preferentially introduced and precipitations of carbon-related phases are less-pronounced at this substrate temperature. The obtained strain in the top Si layer was in the range of −0.6% to −0.7%, which is expected to be adequate for realization of low hole effective mass.

► High hole mobility is expected for compressively strained Si. ► Growth condition to obtain strain-relaxed Si1−xCx on Si(100) was studied. ► Si layer with a strain in the range of −0.6% to −0.7% was obtained.