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Title: Mechanical properties of ion-implanted amorphous silicon.

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Research Org.:
Sandia National Laboratories
Sponsoring Org.:
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DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proposed for publication in Journal of Materials Research.
Country of Publication:
United States

Citation Formats

Follstaedt, David Martin, Myers, Samuel Maxwell, Jr., and Knapp, James Arthur. Mechanical properties of ion-implanted amorphous silicon.. United States: N. p., 2003. Web.
Follstaedt, David Martin, Myers, Samuel Maxwell, Jr., & Knapp, James Arthur. Mechanical properties of ion-implanted amorphous silicon.. United States.
Follstaedt, David Martin, Myers, Samuel Maxwell, Jr., and Knapp, James Arthur. 2003. "Mechanical properties of ion-implanted amorphous silicon.". United States. doi:.
title = {Mechanical properties of ion-implanted amorphous silicon.},
author = {Follstaedt, David Martin and Myers, Samuel Maxwell, Jr. and Knapp, James Arthur},
abstractNote = {},
doi = {},
journal = {Proposed for publication in Journal of Materials Research.},
number = ,
volume = ,
place = {United States},
year = 2003,
month = 6
  • Electrical properties of recrystallized amorphous silicon layers, formed by BF/sup +//sub 2/ implants or Si/sup +/+B/sup +/ implants, have been studied by differential resistivity and Hall-effect measurements. Electrical carrier distribution profiles show that boron atoms inside the amorphized Si layers can be fully activated during recrystallization at 550 /sup 0/C. The mobility is also recovered. However, the tail of the B distribution, located inside a damaged region near the original amorphous-crystalline interface, remains inactive. This inactive tail has been observed for all samples implanted with BF/sup +//sub 2/. Only in a thicker amorphous layer, formed for example by Si/sup +/more » predamage implants, can the entire B profile be activated. The etch rate of amorphous silicon in HF and the effect of fluorine on the recrystallization rate are also reported.« less
  • The wear tracks resulting from unlubricated pin-on-disc tests of 304 stainless steel which was ion implanted with Ti and C have been examined with transmission electron microscopy, scanning electron microscopy, and energy dispersive x-ray spectroscopy. At light pin loads, where the maximum wear depths were reduced by the implantation from approx.1.5 to approx.0.15, nearly continuous amorphous layers containing Ti were found to exist across the wear tracks. However, the amorphous phase was not observed in deeper wear tracks (> or approx. =1 produced by higher loads. This correlation of the presence of the amorphous layer with reduced wearmore » demonstrates that this layer is responsible for the reduction in wear produced by implantation of Ti and C.« less
  • Fluorine distribution profiles for silicon implanted with BF/sup +//sub 2/ have been measured by SIMS as a function of anneal temperature and time. Anomalous migration of fluorine is observed in samples having amorphized layers after implantation. Outdiffusion of fluorine occurs during recrystallization of the amorphous layer, and fluorine collects in regions of residual damage during annealing. This gettering of fluorine by defects illustrates the residual damage below the amorphized layer in samples implanted at room temperature is more difficult to anneal out than that in samples implanted at lower temperture (approx.-110 /sup 0/C).
  • Amorphous silicon-carbon alloy films have been successfully deposited by filtered cathodic vacuum arc technique. The structural and mechanical properties of the films were investigated by using x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, surface profiler and nano-indenter. The silicon content in the films determined by XPS measurement varies from 2.4 to 48 at.%. Both XPS and Raman spectroscopy show the existence of silicon carbide clusters in the films containing intermediate concentration of silicon. The silicon atoms predominantly substitute the carbon atom into the carbon clusters at low silicon concentration, and form amorphous silicon carbide clusters or amorphous silicon clusters at highmore » silicon concentration. The hardness of the films varies from 60 to 22 GPa while the stress reduces from 8.0 to 2.1 GPa.« less
  • Thin-film silicon allows the fabrication of MEMS devices at low processing temperatures, compatible with monolithic integration in advanced electronic circuits, on large-area, low-cost, and flexible substrates. The most relevant thin-film properties for applications as MEMS structural layers are the deposition rate, electrical conductivity, and mechanical stress. In this work, n{sup +}-type doped hydrogenated amorphous and nanocrystalline silicon thin-films were deposited by RF-PECVD, and the influence of the hydrogen dilution in the reactive mixture, the RF-power coupled to the plasma, the substrate temperature, and the deposition pressure on the structural, electrical, and mechanical properties of the films was studied. Three differentmore » types of silicon films were identified, corresponding to three internal structures: (i) porous amorphous silicon, deposited at high rates and presenting tensile mechanical stress and low electrical conductivity, (ii) dense amorphous silicon, deposited at intermediate rates and presenting compressive mechanical stress and higher values of electrical conductivity, and (iii) nanocrystalline silicon, deposited at very low rates and presenting the highest compressive mechanical stress and electrical conductivity. These results show the combinations of electromechanical material properties available in silicon thin-films and thus allow the optimized selection of a thin silicon film for a given MEMS application. Four representative silicon thin-films were chosen to be used as structural material of electrostatically actuated MEMS microresonators fabricated by surface micromachining. The effect of the mechanical stress of the structural layer was observed to have a great impact on the device resonance frequency, quality factor, and actuation force.« less