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Instruments

The operation instructions are given for the following instruments :

1. Cary 500 spectrophotometer

These are instructions for routine spectroscopy using the Cary 500. If you have difficult samples, you will need to explore different options available on this instrument such as single beam mode, baseline correction, and averaging and smoothing routines.

  1. Turn on the computer if necessary and double click on the Cary WinUV icon. You will see a variety of shortcuts to common modes of operation for the spectrometer. If you are simply running a spectrum, double click on the Scan shortcut. (Note you can also just click on the Scan icon from the desktop.)
  2. If the spectrometer is not already turned on, turn it on with the on/off switch at the lower left corner of the instrument. The spectrometer will go through a series of self checks. Messages appear in the lower left corner telling you what is happening. When the spectrometer is ready, the traffic light icon will turn green.
  3. Click the Setup… button on the left side of the window.
    • On the first tab (labeled Cary) you must set the wavelength range over which you wish to scan. You can also set the Y Mode (absorbance, %T, etc) and theScan Control which sets the data accumulation rate. You should set the scan rate (nm/min) and data interval (how many data points per nm).
    • On the Options tab you can choose the mode of operation. Set the SBW (slit bandwidth) to a value less than or equal to the Data Interval which you set on the Cary tab, and choose the beam mode. The choice of "Double" seems to give the best results.
  4. Now you are ready to collect data. Place a cuvette of your solvent or other suitable blank in the cell holder at the rear and place your sample in the front cell holder. Close the cover. Start the spectrum by clicking on the green traffic light Start button. You can click on the double headed arrow to rescale the display to full screen so that you can see what is happening as you go along.
  5. After your spectrum has been collected, you mayprint it (File -> Print) or do further processing such as picking out the peaks. The Peak Picking may be done from the button with the peak on it (second from the right) or from the Graph -> Peak Labels menu option. In either case, you will get a window which allows you to specify peak type, label type, and threshold of detection.

Carry 500

2. TA DSC/TGA

Simultaneous Differential Scanning Calorimetry & Thermogravimetric Analysis
(SDT 2960 Simultaneous DSC-TGA) 

Instructions for the SDT User

  1. Make sure that there are no other applications open which run the SDT, then open the furnace and make sure that both the sample pan (the nearest pan to you) and the reference pan (the other pan) are new and empty.
  2. Close the furnace and tare the instrument before putting your sample by clicking on the Tare Key.
  3. Open again the furnace and put your sample in its proper position and then closed the furnace.
  4. Since the instrument is very sensitive, try not to touch the instrument or the table.
  5. Now is the time to open the software by double clicking on the TA Advantage Control on the desktop.
  6. Click on the Summary (button on the left side of the window to display the set up dialog).
    • In the field of Sample Name, type the name of your sample.
    •  In the field of Data File, type a name for your file.
  7. Click on the Procedure (the 2nd button on the left side of the window).
    • In the Notes field, type your notes (option).
    • Click on the Editor button to display the Method Editor for 2960 SDT {1}.
    • Double click on the Ramp field and then type the temperature rate per minute and the final value of temperature at which you want to stop
    • Click on the Ok field.
  8. Click now on the Operator (the third button on the left side of the window), type your name on the Operator field and then choose the pan type you are using in your experiment.
  9. Open the big bottle of the liquid Nitrogen and set up the actual rate flow at around 130
  10. Take a review and make sure that you didn't miss any of the steps above, then click on Apply button, and finally click on the green triangle ► on the left hand side of the window to run your experiment

TGA

For the theory of DSC/TGA please click here

3. JEOL / NORAN SEM-EDS

Scanning Electron Microscopy (SEM)

A more recent and extremely useful investigative tool is the scanning electron microscope (SEM). The surface of the specimen to be examined is scanned with an electron beam, and the reflected (or back-scattered) beam of electrons is collected, then displayed at the same scanning rate on a cathode ray tube (similar to a TV screen). The image on the screen, which may be photographed, represents the surface features of the specimen. The surface may or may not be polished and etched, but it must be electrically conductive; a very thin metallic surface coating must be applied to nonconductive materials. Magnifications ranging from 10 to in excess of 50,000 diameters are possible, as are also very great depth-of-field. Accessory equipment permits qualitative and semiquantitative analysis of the elemental composition of very localized surface areas.

The figure bellow schematically illustrates its principles of operation. Basically, an electron gun produces an electron beam in an evacuated column which is focused and directed so that it impinges on a small spot on the target. Scanning coils allow the beam to scan a small area of surface of the sample. Low-angle backscattered electrons interact with the protuberances of the surface and generate secondary backscattered electrons to produce an electronic signal, which in tern produces an image having a depth of field.

SEM

 

Instructions for the operation of the JEOL SEM Model JSM-5310LV

  1. Make sure that the detector is filled with liquid N2.
  2. When the HT (high-tension) key is ready (means that the vacuum LV control is fine), push the VENT key and wait for a short time.
  3. Open the sample chamber and insert your sample stub (wearing gloves) into the brass cup, and gently tighten the set screw.
  4. Close the door to the sample chamber and lock the clasp.
  5. Push EVAC and wait for a few minutes.
  6. When HT is ready and the VA is 100 %, push HT by which the image will display.
  7. Depending on the sample, set up the accelerating voltage on 10 kV, Working Distance (WD) on 17 mm (normally 20 mm).
  8. Set up the Spot Size (SS) on 15 mm (it should be less than 17 mm for image).
  9. Magnifications ranging from X35 to in excess of X100,000 diameters are possible.
  10. Focus the image using the focus coarse and fine knobs.
  11.  Adjust the brightness and contrast controls to your liking.
  12. Push the key
  13. Now is the time to operate the Noran EDS Voyager by double clicking on the image display on the desktop.
  14. Click on Tools, then click on Spectrum Attributes and type values of Acc. Voltage, Magnification, Working Distance, Spot Size and Beam Current. Then close the window.
  15. To quantify your sample elements, click on Analyze, then on Quant Periodic Table.
  16. Now click on Spectral Display to get the spectrum.
  17. TO SAVE SPECTRUM, go to File, then save as. Choose a name for your file, click on OK and close the window.
  18. Click on Tools, then on Image Display by which you'll get the image.
  19. SAVE IMAGE, go to File, then save as. Choose a name for your image, click on OK, and close the window

 

 

4. Kurt J. Lesker RF Sputtering system

Procedures for operating the Fisk RF magnetron sputtering system
   I. Basic system information :

  • Vendor : Kurt J. Lesker Inc.
  • Model : Manitou systems Inc., model PB-3, 300 Watt (max), 13.65 MHz RF power system.
  • Input power : 115 V AC, 50/60 Hz, 1 phase.
  • RF output power : up to 300 Watt maximum.
  • Output Frequency : 13.56 MHz.
  • Output impedance :  50 ohm resistive.
  • Matching network circuit topology : "L" configuration utilizing two variable capacitors and a fixed inductor
  • Operating pressure : 5 to 200 mTorr.

II. Sputtering head and target :

  • One head, Torus 2-C, required water cooling at flow rate ~ 0.5 gallon/minute.
  • Target (deposition material) : planar, 2" diameter (1.9" with copper cup imbedded in the case of nonmetal target), 1/4" thick (1/8" with copper cup).
  • Warning: Dark space shield, target hold down ring and target position must be very well balanced and symmetric in order to avoid sparking of the target.
  • At least, the target hold down ring, dark space shield and all the nearby poles, holders... need to be well cleaned to avoid contamination and sputtering failure. Cleaning is especially required after a nonmetal sputtering to avoid accumulation of charges (all the surrounding must be well grounded)
  • Gloves must be worn in handling all the items in the vacuum chamber.

III. Loading the target and sample(s) :

  1. Remove the dark space shield.
  2. Lift off the target hold down ring.
  3. Carefully place the target on top of the copper cooling well, making sure that it is well centered.
  4. Put back the target hold down ring, again, making sure that it is symmetric and balanced
  5. Put back the dark space shield, making sure there is indeed a space between the shield and the target.
  6. Generally, for making contact on device or for making thin film, the sample to target distance is 2-3".  2.5" is usually the choice (for ultra thin film, < 40 A0, 5" is recommended).
  7.  Before sputtering, it is a good practice to use the ohmmeter to test the resistance between the target and the dark space shield as well as between the target and the base of the vacuum system to make sure that there is no shorting (dark space shield and the base must be grounded).
  8. Check the water supply by turning in on, making sure that there are water flow out of the returning pipes (water is needed for both the Turbo pump and the cooling of the sputtering target).

IV. Operation :

  1. Pumping the system to base pressure near ~10-6 Torr ( first mechanical pump then Turbo pump - remember to turn on the water before starting the Turbo, the "accelerating" LED first lights up, one should wait until the "normal operation" LED to light up before leaving the system).
    • Note : Channel 1 can only read up to 10-3 Torr even the system is already below that pressure. One needs to use "Ch.1-ion gauge" to get lower pressure reading. Normally, the ion gauge should be turn off when unattended.
  2. Turn on the RF power button.
  3. Open the Ar line, turning on the Ar input switch, making sure the control nod is slightly open (~1/2 circle counter clockwise from the closed position).  Ar flow pressure is around 10 - 20 psi.
  4. The system pressure will go up but we need to bring it up further to 10-1 Torr range by nearly close the hi-vac gauge (clockwise). This is to ignite the plasma. It won't come up at pressure below 10-2 Torr. At this time, the plasma should come up. Now comes the most critical part of the sputtering process - impedance matching ! - to maintain the appropriate forward power while minimize the reflected power ( < 5 Watt, 0 Watt desirable ).
  5. The forward power is material dependent, for metal such as Au, 50 Watt or less will be good. If higher power is used for metal target, the target may crack. For semiconductor and insulator targets, higher power is required but be careful when apply more than 100 Watt ( < 100 Watt is recommended first ) - extreme caution must be taken - contact vendor if necessary
  6. The impedance matching is done by turning the Tune Adjust and the Load Adjust. The reflected power can be read by holding down the Meter Mode button.The tuning is done in integral steps while monitoring the forward and the reflected power. First try to get the wanted forward power then try to minimize the reflected power - one might need  to go back to the forward adjustment since the forward and the reflected reading are mutually dependent. Note that the optimized range for the tune adjust and load adjust vary with different targets but generally (for metal, not necessarily for semiconductor and insulator), the tune adjust range is around 40 -60 (45-50 optimum) whereas for load adjust, it is around 80 -100 (optimized near 100 ).
    • Warning :  The starting position for the tuning should never be set originally at optimized position since it can cause "out of range to tune" problem !
  7. After the impedance matching, the pressure is still in the 10-1 Torr range. At this point, one need to bring it down to the desired pressure level (usually 10-2 Torr range) before the sputtering deposition can be started (up to now, we only pre-sputtering with shutter on).  
    • Note : The operating pressure for metal target is generally 10- 50 milliTorr. For semiconductor and insulator targets, higher pressure must be used (60 - 200 milliTorr) to maintain the plasma.
  8. The bringing down of the pressure is also critical for the sputtering process. It is done by tuning very slowly the hi-vac gauge counter clockwise (open) while monitoring the reflected power. In order to maintain the minimum reflected power, one has to slightly adjust the Tune Adjust and the Load Adjust until the desired pressure is reached.
  9. One can now open the shutter and start timing the sputtering deposition.
  10. During this sputtering process, one may have to continue checking the reflected power and may have to do small adjustment again. This is a must for non-metal target !
  11. After finishing, turn off RF power, close Ar line, turn off water, Turbo pump and mechanical pump then slowly venting the system. Waiting time for the system to cool down is required if the sample is annealed prior/during/after the deposition.
  12. Lift off the bell jar, unload the sample and safely packing it.
  13. Finally, remove the target and clean the environment (target hold down ring, dark space shield, poles, holders...). This is especially required if another target material is going to be used ! 

Sputtering System