What is SEM? TM-1000 Tabletop Microscope

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Camron Sullivan
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1 What is SEM? TM-1000 Tabletop Microscope

2 SEM vs OM SEM (Scanning Electron Microscope) OM (Optical Microscope) Backscattered (BSE) Image (Vacuum : 5Pa) Sample : Bulb filament Magnification : 500X

3 Hitachi S-3000N SEM Electron Gun BSE Detector SE Detector Monitor Sample Stage Column Unit Display Unit

4 World s highest resolution SEM vs TM kg S mm 30kg TM kg 513mm 478mm 896mm 1000mm 25kg Highest Mag Total weight Foot print List price S ,000,000X 1,133 kg 3.5m x 3.5m TM ,000X 88 kg 1m x 1m

5 OM vs SEM

OM SEM light Electron source Condenser lens Objective lens sample sample Condenser lens Objective lens (scan) Deflection coil SE Detector Projection lens

6 OM SEM light Electron source Condenser lens Objective lens sample sample Condenser lens Objective lens (scan) Deflection coil SE Detector Projection lens Screen 像 O M 像 Screen T E M Transmission Electron Microscope Projection lens sample 像 C R T S E M Scanning Electron Microscope Projection image Surface mage

7 OM TM-1000 Hardware Performance Application Accelerating voltage - 15 kv source light electron circumstance atmosphere Low vacuum lens glass electromagnetic detector - Solid-state BSE detector image - BSE image resolution um - 30 nm Depth of focus(500x) Shallow (2-3 um) deep ( - 1 mm) color color Black/white magnification kx 20-10kX Field of view wide wide preparation easy easy Sample size large large

8 Theory of SEM Scanning Electron Microscope

9 SEM Configuration High Voltage (PC) Anode filament COND lens wehnelt Video signal PC Monitor DEF coil OBJ lens BSE Detector Scanned electron DEF amp BSE Sample chamber sample Y scan Amplifier X scan Image area L Mag = L / W Vacuum pump W

10 Electron Gun

11 Power supply Tungsten filament Bias voltage wehnelt Accelerating voltage anode Thermal emission electron gun Tungsten filament tip (SEM image) Electron source Working pressure Filament lifetime - 30 um 10-3 Pa Approx. 50 hr

12 Electromagnetic lens

13 Aperture Excluding scattered electrons Condenser lens Making spot size smaller Deflection coil Making electrons scan Astigmatism correction coil Objective lens Image focusing

14 Magnification in the SEM Scanned electron on CRT Scanned electron L Scanning (X) Scanning(Y) l S E M Pixel sample C R T Magnification (M) =L / l (ratio of scanned area on the sample and on the Monitor)

15 Information from sample - Difference between SE and BSE - SE BSE : Secondary Electrons : Backscattered Electrons

16 Sample interaction by electrons Primary electrons Secondary electrons X-ray Backscattered electrons BSE CL 1 SE ,000 Energy (ev) (at accelerating voltage : 10kV) Absorbed current sample EBIC TE (Transmitted electrons)

17 Difference between SE and BSE Primary electrons BSE Detector Emission is depending on mean atomic number and crystal orientation BSE SE Emission from surface and representing surface topography. SE Detector (BSE emission area) several 10nm - 10nm(SE emission area) sample

18 Difference between SE and BSE SE image (Topographic information) BSE image (Topographic + Composite information) Sample : solder Mag : 800X

19 Observation under low vacuum

20 Evacuation system for low vacuum operation Filament 10-3 Pa V Gun chamber Orifice :0.1mmdia. Valve Close: several Pa Valve OPEN:30-50Pa Air leak valve for lower vacuum Air leak valve for sample exchange Sample chamber Intermediate TMP chamber sample IP Evacuation port ATH31(Alcatel) 30 l/s Exhaust port MVP l/min Diaphram pump

21 Advantages of observation under low vacuum - Non-conductive sample can be observed without metal coating - Sample containing water or oil can be also observed - Time and cost saving against metal coating - Omission of preparation against biological sample

22 Advantage of low vacuum High vacuum Low vacuum Charge-up phenomenon Sample : rubber Magnification : 1,000X

Advantage of low vacuum High vacuum Sample containing

vacuum Sample containing water must be dehydrated and

23 Advantage of low vacuum High vacuum Sample containing water is easily dried and shrunk under high vacuum Low vacuum Sample containing water must be dehydrated and dried before introducing into high vacuum which takes about one day. Water evaporation can be suppressed under low vacuum Sample : rose petal Magnification : 1,000X

24 Principle of observation at low vacuum - charge-up prevention - Primary electrons OBJ lens Non-conductive sample High vacuum ( Pa) Metal coating -

25 Principle of observation at low vacuum - charge-up prevention - Primary electrons OBJ lens - Charge-up Non-conductive sample High vacuum ( Pa)

26 Principle of observation at low vacuum - charge-up prevention - Primary electrons OBJ lens Neutralization M M Non-conductive sample 高真空雰囲気 Low vacuum ( ~10 270Pa) -4 Pa)

27 Principle of observation at low vacuum - charge-up prevention - Primary electrons OBJ lens BSE Detector SE Detector +10kV M Non-conductive sample Low vacuum (1-270Pa)

NNIN Nanotechnology Education

NNIN Nanotechnology Education Teacher s Preparatory Guide Powers of Ten with the Morpho Butterfly Purpose: This activity is designed to help students understand the concept of scale and magnification when