Characterization of crystalline structures of SiGe substrate formed by traveling liquidus-zone method for devices with Ge/SiGe structures

Bulk and surface crystalline structures of the SiGe (001) substrate formed by the traveling liquidus-zone (TLZ) method were characterized. In addition, a possibility of the SiGe substrate as a seed for the strained-Ge/SiGe structures in optoelectronic and electronic devices has been investigated through surveying cleaning methods of the SiGe surface. It was found that the TLZ method can provide the high quality SiGe substrate with the threading dislocation density of the range from 4 × 105 to 6 × 107 cm− 2. The high quality SiGe substrate treated with the appropriate chemical and thermal cleaning makes it possible to grow the epitaxial Ge layer with large strain of 1.3%. Consequently, we clarified that the high quality SiGe substrate fabricated by the TLZ method has a high potential as the seed for the strained-Ge layer in the devices.