Nanocavity effects on misfit accommodation in semiconductors

Technical Report · Tue Apr 01 04:00:00 EST 1997

DOI:https://doi.org/10.2172/468586· OSTI ID:468586

Myers, S M; Follstaedt, D M; Floro, J A; Lee, S R; Dawson, L R; Reno, J L

The authors report an experimental and theoretical examination of the interaction of dislocations with microscopic cavities in semiconductors and the consequences for strain relaxation in heteroepitaxial structures. Dislocation-mediated relaxation and control of the resulting defect microstructure is central to the exploitation of such heterostructures in devices, and they demonstrate here that the introduction of nanometer-scale voids provides a means of strongly influencing this microstructural evolution. Methods for nanocavity formation using He ion implantation and annealing were developed for Si, SiGe on Si, GaAs, and InGaAs on GaAs. In detailed microstructural studies of SiGe on Si, cavities in the interfacial zone were shown to bind dislocations strongly. This effect reduced the excursion of dislocations into the nearby matrix, although threads into the SiGe overlayer were not eliminated. Interfacial cavities also increased the rate of stress relaxation by more than an order of magnitude as a result of enhanced nucleation of misfit dislocations. Further, in the presence of such cavities, the development of thickness variations in the overlayer during relaxation was suppressed. A theoretical model was developed to describe semiquantitatively the forces on dislocations arising from the combined influences of cavities, misfit strain, and the external surface. Predictions of this model are in accord with microstructural observations.

• Research Organization: Sandia National Labs., Albuquerque, NM (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 468586
• Report Number(s): SAND--97-0724; ON: DE97005267
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
DISLOCATIONS
EXPERIMENTAL DATA
GALLIUM ARSENIDES
GERMANIDES
HELIUM IONS
HETEROJUNCTIONS
INDIUM ARSENIDES
ION IMPLANTATION
MICROSTRUCTURE
PHYSICAL RADIATION EFFECTS
SEMICONDUCTOR DEVICES
SILICON COMPOUNDS
STRESS RELAXATION
THEORETICAL DATA
VOIDS