AUTHOR=Claflin B. , Grzybowski G. J. , Ware M. E. , Zollner S. , Kiefer A. M. 

TITLE=Process for Growth of Group-IV Alloys Containing Tin by Remote Plasma Enhanced Chemical Vapor Deposition

JOURNAL=Frontiers in Materials

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2020.00044

DOI=10.3389/fmats.2020.00044

ISSN=2296-8016

ABSTRACT=<p>A remote plasma enhanced chemical vapor deposition (CVD) process using GeH<sub>4</sub>, SiH<sub>4</sub>, and SnCl<sub>4</sub> precursors has been developed for epitaxial growth of group-IV alloys directly on Si (100) substrates, without the need for buffer layers. X-ray diffraction measurements of a representative Ge<sub>1</sub><sub>–x</sub>Sn<sub><italic>x</italic></sub> sample which is 233 nm thick, with <italic>x</italic> = 9.6% show it to be highly oriented along the [001] direction and nearly relaxed, with 0.37% compressive strain. Ellipsometry measurements provide a pseudo-dielectric function which is well fitted by a 3-layer (substrate/alloy/surface oxide) model. Cross-sectional transmission-electron-microscope images show a highly defective interface layer, ∼ 60 nm thick, containing edge dislocations and stacking faults; above this layer, the lattice is well-ordered, with a much lower density of defects. Atomic force microscopy measurements show an RMS roughness of 1.2 nm for this film.</p>