Engineering of boron-induced dislocation loops for efficient room-temperature silicon light-emitting diodes
- Advanced Technology Institute, School of Electronics and Physical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH (United Kingdom)
We have studied the role of boron ion energy in the engineering of dislocation loops for silicon light-emitting diodes (LEDs). Boron ions from 10 to 80 keV were implanted in (100) Si at ambient temperature, to a constant fluence of 1x10{sup 15} ions/cm{sup 2}. After irradiation the samples were annealed for 20 min at 950 deg. C by rapid thermal annealing. The samples were analyzed by transmission electron microscopy and Rutherford backscattering spectroscopy. It was found that the applied ion implantation/thermal processing induces interstitial perfect and faulted dislocation loops in {l_brace}111{r_brace} habit planes, with Burgers vectors a/2<110> and a/3<111>, respectively. The loops are located around the projected ion range, but stretch in depth approximately to the end of range. Their size and distribution depend strongly on the applied ion energy. In the 10 keV boron-implanted samples the loops are shallow, with a mean size of {approx}30 nm for faulted loops and {approx}75 nm for perfect loops. Higher energies yield buried, large, and irregularly shaped perfect loops, up to {approx}500 nm, coexisting with much smaller faulted loops. In the latter case much more Si interstitials are bounded by the loops, which are assigned to a higher supersaturation of interstitials in as-implanted samples, due to separated Frenkel pairs. An interesting phenomenon was found: the perfect loops achieved a steady-state maximum size when the ion energy reached 40 keV. Further increase of the ion energy only increased the number of these large loops and made them bury deeper in the substrate. The results of this work contribute to laying a solid ground in controlling the size and distribution of dislocation loops in the fabrication of silicon LEDs.
- OSTI ID:
- 20668274
- Journal Information:
- Journal of Applied Physics, Vol. 97, Issue 7; Other Information: DOI: 10.1063/1.1866492; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMBIENT TEMPERATURE
ANNEALING
BORON IONS
BURGERS VECTOR
DISLOCATIONS
ENERGY YIELD
FABRICATION
FRENKEL DEFECTS
HABIT PLANES
INTERSTITIALS
ION BEAMS
ION IMPLANTATION
KEV RANGE 10-100
LIGHT EMITTING DIODES
RUTHERFORD BACKSCATTERING SPECTROSCOPY
SEMICONDUCTOR MATERIALS
SILICON
SUPERSATURATION
TEMPERATURE RANGE 0273-0400 K
TRANSMISSION ELECTRON MICROSCOPY