of Silicon Germanium Alloys

Silicon and germanium exhibit complete solid solubility for all binary concentrations. However, the growth of single crystalline SiGe alloys by bulk growth processes is hindered by the relatively wide separation of the solidus and liquidus lines. Previous research has yielded single crystals grown by the Czochralski method which are limited to only a few atomic percent of solute (Si or Ge), and even these crystals must be grown slowly (on the order of a millimeter per hour). On both a macroscopic and a microscopic scale, these crystals exhibit large axial variation in the solute distribution. This research investigates SixGeix alloys with O<x 0.05. Several growth parameters that affect axial and radial segregation as well as growth interface stability and microsegregation are investigated. Specifically, this research investigates methods to influence the Si axial composition fluctuations, minimize dislocation density in the crystal, and allow for a relatively fast growth rate while maintaining single crystalline growth. In the reported growth experiments, single crystalline growth was limited to boule concentrations of less than 1 at % Si. For this concentration range of Si, the growth rat