Engineering of Strain Relaxation Using Focused Ion Beams |
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Materials:
Semiconductors
Application: Electronic Technique: Processing |
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Lattice mismatch in heteroepitaxial semiconductor systems remains one of the greatest barriers to the use of otherwise promising film combinations. Many III-V semiconductor systems have bandgaps that make the desirable for high efficiency and high output optical applications, but their use thus far has been limited by the availability of lattice matched substrates. Growth upon commercially available GaAs and InP wafer substrates produces a large mismatch strain, which results in defects or surface roughening that degrade film properties. One proposed method for reducing strain and defect density in mismatched heteroepitaxial systems is growth upon patterned substrates. The goal of this project is to use a focused ion beam (FIB) to modify III-V semiconductor substrates for subsequent growth of low strain and low defect density films. A variety of substrate modification approaches are being researched, including direct 3-D substrate patterning, 3-D strained-layer-on-substrate patterning, and FIB induced assembly of nanostructure patterns. This project is using a UHV FIB column integrated with an existing MBE/STM system so that all patterning and growth steps may be carried out completely in vacuo. As part of this work ion-solid interactions with GaAs, AlAs, InP, and InAs are being examined to determine how those materials may be best modified and patterned using the FIB. Once mismatched films have been grown on modified substrates their degree of strain relaxation and defect reduction will be characterized by plane-view and cross-sectional TEM, XRD, and AFM. |
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Materials Science and Engineering, University of Michigan
Sections
- Engineering of Strain Relaxation Using Focused Ion Beams
| P.I.: | Joanna Mirecki-Millunchick |
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| Sponsor: | Army Research Office (ARO) |