Defect studies in Ge and GeSn thin films grown on Si

Silicon (Si) is often used in electronics because of its beneficial conductive properties and cost efficiency. However, it has poor optical properties in the infrared. Si infrared photonic devices could be used for a number of military and civilian applications. One approach to solving this problem is to use epitaxy to grow materials with more favorable optical properties on top of Si, such as germanium (Ge) and germanium tin (GeSn). One challenge for epitaxy is minimizing threading dislocations in the epitaxial layers due to lattice mismatch. In this work, we investigate the quality of Ge and GeSn materials grown on Si using a new remote plasma enhanced chemical vapor deposition (CVD) process. The newly grown material was subjected to etch pit density tests in order to determine the density of threading dislocations. The results show that using this new method results in high quality achieved using traditional CVD methods while also increasing growth rates.