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SUMMARY:Recent advances in specimen preparation and manipulation technolog
 y for SEM/FIB and TEM - Alan C Robins \, E A Fischione Instruments Inc
DTSTART:20060425T140000Z
DTEND:20060425T150000Z
UID:TALK4857@talks.cam.ac.uk
CONTACT:Edmund Ward
DESCRIPTION:The use of Field Emission Guns on modern TEM and SEM instrumen
 tation has led to significant improvements in imaging and analytical perfo
 rmance. Specimens have also grown in diversity and complexity demanding mo
 re advanced specimen preparation technologies.\n\nTypical specimen prepara
 tion starts by choosing a suitable site from the bulk specimen. Care has t
 o be taken at every stage to minimise the damage introduced to the specime
 n from cutting\, grinding or polishing. The next stage involves dimple gri
 nding of the specimen which is performed to reduce the time taken to Ion M
 ill the specimen to perforation. During Ion Milling the energy\, current\,
  angle and temperature will affect the final result. With many new materia
 ls phase changes can result if the temperature is not controlled. The ulti
 mate speed of ion milling may well be at the detriment to the sample. Befo
 re examination of the specimen in the microscope it is important to remove
  any hydrocarbon contamination from both the specimen and holder. Typicall
 y both are cleaned prior to insertion in the electron microscope using a p
 lasma cleaner. Removal of this contamination will prevent the deposition o
 f carbon on the sample during imaging or analysis.\n\nNew Preparation Tech
 nologies such as FIB allow the preparation of very site specific areas of 
 the specimen. The ultimate specimen however can possess some features whic
 h are not ideal for high-resolution or analytical microscopy. These defect
 s include curtaining and amorphous contamination which affect the physical
  and electrical properties. Using a focused low energy argon ion source to
  scan and image the lamella\, amorphous material can be removed. The ultim
 ate sample is then suitable for characterisation by TEM.\n\nImaging of spe
 cimens in STEM using a HAADF detector with a DQE in excess of 98 per cent 
 results in single electron detection efficiency. In addition\, combining S
 TEM with tomography allows the three-dimensional reconstruction of Materia
 ls Science samples without significant contributions from diffraction cont
 rast during data collection. A high tilt capability combined with a large 
 field of view in a narrow gap pole piece is now necessary. Biasing of samp
 les during tilting and acquiring electron holograms now allows the reconst
 ruction of electric fields in semiconductor device samples in three dimens
 ions.\n\nSpecimen Preparation Technology for SEM has also become more comp
 lex. Field Emission SEMs have high resolution at low accelerating voltages
 . For EBSD the sample surface has to remain free of artefacts at the atomi
 c level. Cleaving\, polishing and cleaning of the specimen surface is no l
 onger a viable method. Combining technologies such as Ion Beam Etching\, R
 eactive Ion Beam Etching\, Plasma Cleaning and Coating in a single vacuum 
 chamber reduces specimen artefacts.\n\nUsing the correct combination of te
 chnologies can result in optimising representative data collection from sp
 ecimens.
LOCATION:T001 [Tower Seminar Room]\, Materials Science and Metallurgy\, De
 partment of
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