On the origin of the uniaxial strain induced in Si/Ge heterostructures with selective ion implantation technique

• Published in: Journal of crystal growth Vol. 378; pp. 251 - 253
• Main Authors: Sawano, K., Hoshi, Y., Nagakura, S., Arimoto, K., Nakagawa, K., Usami, N., Shiraki, Y.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.09.2013; Elsevier
• Subjects: A1. Defects; A1. Surface structure; A3. Molecular beam epitaxy; Arrays; B1. Germanium silicon alloys; B2. Semiconducting silicon compounds; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects and impurities in crystals; microstructure; Dislocations; Exact sciences and technology; Germanium; Ion implantation; Linear defects: dislocations, disclinations; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Physics; Silicon; Silicon germanides; Strain; Strain relaxation; Structure of solids and liquids; crystallography; A3. Molecular beam epitaxy; B1. Germanium silicon alloys; B2. Semiconducting silicon compounds; A1. Surface structure; A1. Defects; Misfit dislocations; Ge-Si alloys; XRD; Plastic deformation; Surface structure; Silicon compounds; Stress relaxation; Calcium nitride; Molecular beam epitaxy; Uniaxial strain; Stress effects; Buffer layer; Ion implantation; Semiconductor materials; Mechanical properties; Template reaction; Germanium alloys; Silicon alloys; Strained layer; Shear stress; Arrays; Defect formation; Heterostructures
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2012.12.100

We fabricate uniaxially strained SiGe buffer layers by the selective ion implantation technique, where laterally selective ion implantation with a stripe pattern is performed into a Si substrate, followed by SiGe overgrowth in the whole region. Large strain relaxation of SiGe occurs only in the ion-implanted area. This relaxed SiGe provides shear stress to the neighboring strained SiGe in the unimplanted area, leading to the uniaxial strain relaxation. The observed surface exhibits array of one direction steps which corresponds to misfit dislocations. Relaxation ratios estimated from the dislocation periodicities agree very well with those obtained from x-ray diffraction, indicating that the uniaxial strain is induced by the plastic deformation via dislocation generation. This fact means that the induced uniaxial strain is very stable, and hence, the SiGe layer can be used as a promising template for uniaxially strained Si/Ge channels grown on it. ► Uniaxially strained SiGe layers are fabricated by the selective ion implantation technique. ► The origin of the uniaxial strain is plastic deformation via directional dislocation generation. ► Observation of one directional surface steps indicates the one directional misfit dislocations. ► This technique opens the way to realize high mobility Si/Ge channels with uniaxial strain.