Si1-xGex layers were deposited using Si2H6/GeH4 and Si3H8/GeH4 by ultrahigh vacuum chemical vapor deposition, and the effect of the Si precursor type on surface roughnening is investigated. The root mean square (RMS) of surface roughness of Si1-xGex layers that were deposited using either Si2H6 or Si3H8 was increased gradually with the increasing film thickness, resulting in an increase in the amplitude of the wavy surface below the critical thickness for the formation of threading dislocations. The residual strain in SiGe with Si2H6 was decreased significantly through the defect formation with an abrupt increase in RMS roughness for the thickness larger than the critical thickness. For the SiGe layer with Si3H8, RMS roughness of the SiGe layer was increased gradually and monotonically, while the residual strain was decreased gradually above the critical thickness. Therefore, the use of a Si3H8 precursor as a silicon source gas can be helpful to control the flat interface for heteroepitaxial growth.
|Journal||Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films|
|Publication status||Published - 2017 Jul 1|
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films