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XRR - Main Campus Rigaku Ultima and Philips

XRR - Main Campus Rigaku Ultima and Philips

XRR

Main Campus Rigaku Ultima (Preferred)

Webpage: http://tmi.utexas.edu/core-facilities/equipment/rigaku-ultima-iv/
Location: ETC 9.142
Contact for training: Dr. Steve Swinnea (swinnea@che.utexas.edu)

The Main Campus XRR is Highly automated, slightly lower resolution, horizontal sample stage. No hardware change required for XRD/XRR. Gloves are difficult to find in this lab. See if you can borrow some from a nearby lab or bring your own.

For those who are interested, Professor Swinnea teaches an X-ray scattering theory course in the fall and a hands-on lab in the spring. The spring course can be taken without the theory course. Ask Swinnea for more details.

Operating conditions are set either through XG Operation application (preferred) or through experimental parameters

  • Idle conditions - 20 kV / 2 mA

  • Normal operating conditions - 40kV / 44 mA.

Operating Procedure -- SDM Fall 2016

  1. Make sure experiment is not in progress.

  2. Insert sample

    1. Gloves are difficult to find in this lab. See if you can borrow some from a nearby lab or bring your own.

    2. Press Door Lock button on front of instrument. When the yellow lamp starts blinking and beeping, the door can be opened.

    3. Add the Ni filter to remove the Cu k-alpha second peak, if needed (not normally needed for XRR)

    4. Insert sample in standard sample attachment stage. For XRR, the sample will sit horizontally during the entire measurement, so no tape is needed to hold the sample in place. See example below.

image-20240704-123935.png
XRR sample laying on stage. Note: the sample does not need any support, e.g. tape, to stay in place because the stage does not move during the measurement

  1. Close enclosure door carefully. Press Door Lock button. Beeping should stop.

  2. Turn on the X-ray source in the XG operation RINT2200 window

    1. Voltage X-ray tube to 20 → 40 kV

    2. Current to 2 → 44 mA

    3. ‘Set’ button

    4. NOTE: you may open the doors later on when the X-ray tube is turned on to adjust/swap a samples. Opening the door automatically closes the shutter from the X-ray tube

  3. At the computer, open the Standard Measurement application.

    1. Start\Programs\Rigaku\Right Measurement\Thin Film

  4. In the Thin Film Measurement window the pops up, click on “Profile” to start the Profile Measurement window to bring up XRD and XRR

  5. In the Profile Measurement window that pops up (see "Profile Measurement Window" image below):

    1. Do not use/modify the settings that automatically show up -- those are another researcher's!!!

    2. 'File\Open' and select the default option under 'C:\Windmax\Apps\Inpmeas\default.mcd'

    3. Change the Folder name to reflect your own directory

      image-20240704-124009.png
      "old" Profile Measurement Window

    4. Make sure "Yes" is selected for the type of measurement you want (Reflectivity), and "No" is selected for the other options

  6. Select ‘Show measurement conditions’ to open up a different “Profile Measurement” window

    image-20240704-124041.png
    "new" Profile Measurement Window with recommended scan settings

  7. In this new Profile Measurement window

    1. Go to the ‘No. 1’ tab, which corresponds to the No. 1 row in the old Profile Measurement window

  8. Change sample thickness to your wafer+film thickness in mm

    1. Si wafers for ESW Bi studies are 350-380 um, so use 0.38 mm

    2. Most other wafers are between 350-500 um

  9. Perform Specimen Alignment (i.e. rough alignment)

    1. Keep the default sequence and boxes checked

      1. sequence: ‘omega->Z’

      2. check the ‘Set ‘Omega = two theta/2’

      3. Set the thickness in nm for the entire sample, i.e. substrate + epi film

      4. Threshold --> 1000 (this is the default value)

    2. Back in the old Profile Measurement Window make sure the option you set up has a ‘yes’ next to it perform that particular measurement

    3. ‘Execute’

  10. Precise alignment

    1. Uncheck the ‘Delete previous settings’ option

    2. Keep the default settings and sequence

      1. Scan Sequence --> 'omega > z > Rx'

      2. Repeat cycles --> '2'

      3. Threshold --> '1000'

      4. Peak Search Method --> 'Peak top'

      5. Two Theta/Omega --> '0.6000'

      6. ATT --> 1/800

      7. DS --> 0.10mm

      8. SS --> 0.20mm

      9. RS --> 0.20mm

    3. Back in the old Profile Measurement Window make sure the option you set up has a ‘yes’ next to it perform that particular measurement

    4. ‘Execute’

    5. NOTE: you will be prompted to overwrite your previous sample file, which is okay because it has data for the rough alignment and you don't need to save it. If you happen to want to save the rough alignment data, change the filename back in the old Profile Measurement window

  11. After the Precise measurement is complete, make a note of the settings and critical angle (aka ‘Two-theta omega’ value)

  12. Preliminary measurement

    1. Run/Execute with the default attenuator setting (1/800) and speed, see example below for a completed scan

      image-20240704-124101.png
      Result of preliminary measurement/scan

  13. Based on the output curve, divide the curve into regions based on the decade of the cps observed. At each decade cps change, adjust the attenuator, see example below from the manual

    image-20240704-124115.png
    Example from manual of how to set up scanning ranges based on the intensity decades observed during the preliminary measurement

    1. Set the scan parameters to the ABCDE range determined by adjusting

      1. 'Start' column

      2. 'Stop' column

      3. 'ATT' column, for attenuation setting

    2. ‘Connect all ranges’

    3. ‘Execute’

  14. Data is saved in C:\Windmax\Data\<your folder selected earlier>

    1. You might have to adjust the ABCDE range to get the splicing to make curves splice correctly to avoid extra data analysis, e.g. re-normalization

    2. Use a flash drive to remove your data

  15. After all measurements are finished

    1. Unload last sample

    2. Get data off the computer (email or flash drive)

    3. Fill out the usage database on the TMI website

      1. tmi.utexas.edu/XRD/logs/log.php

      2. Also on the desktop ‘X-ray Facility Use Report’

      3. If your name is not there, enter your info at the bottom of the webpage

      4. Enter your account number

    4. Close all the software windows except the XG Operation window

    5. Set the Tube voltage and current back to their default values unless there is another user after you

      1. 40 → 20 kV and 44 → 2 mA

      2. ‘Set’ button

Troubleshooting

  • Issue: no counts measured during coarse alignment scan for XRR

    • Check hardware configuration in Rigaku control panel. If settings are not changed back after a monochrometer user, scans won't work. Do not try this without being shown how. If this is the problem, let Dr. Swinnea know.

    • Aligning to small samples is difficult in this instrument. If you have a small sample (< 1/4 3" wafer), try Rx scans first, changing divergence slit size.

  • Issue: no fringes in final scan, critical angle displaced, weird curve shapes for 2theta and omega alignment scans

    • Try reloading .mcd file - this issue can occur if previous users have saved changes to default file. Backup version is in Emily's folder.

  • Issue: no ascii file saved after executing scan, and no option under file menu to export one

    • Sometimes Dr. Swinnea turns this option off. In the "Execute Measurement" window, go to edit --> saved data type --> binary & text

Old/incomplete Operating Procedure -- Pre-fall 2016

  1. Make sure experiment is not in progress. Press Door Lock button on front of instrument. When the yellow lamp starts blinking and beeping, the door can be opened.

  2. Insert sample in standard sample attachment stage

  3. Close enclosure door carefully. Press Door Lock button. Beeping should stop.

  4. At the computer, open the Standard Measurement application. There are 2 components in this tool: conditions and measurements. Conditions contain parameters such as min/max 2theta, run type (continuous vs. step scan), kV, mA, slit conditions. Open conditions using the icon that looks like a finger pointing at a printed page. Find a condition that matches the desired parameters or make a new one.

  5. Close conditions window to return to measurements window. Change the filename field, the comment field, and most importantly, the condition field. The condition should be set to the same condition number chosen in step 4.

  6. Click left icon to start scan. After a short pause, there may be a dialog box asking that a certain slit (i.e. tube side divergence slit) be changed. Look into enclosure to make sure slit is installed (usually 10 mm DHL). If not you may press the Door Lock button to enter the enclosure and install the correct slit. Make sure to close the door correctly.

  7. Upon accepting the dialog mentioned in the previous step, the experiment will start.

  8. When run finishes, shutter will close and doors may be opened for sample material.

  9. Enter use of instrument in the log book.

Pickle Philips X-pert XRR (OLD X-ray system, replaced by Rigaku)

Contact: Johnny, Jesse, LASE group.

Manual alignment, vertical sample stage, high resolution, hardware change required between XRD / XRR. More convenient, but more likely to experience technical difficulties.

Setting up XRR hardware

  1. Have Johnny or Jesse change detector from XRD to XRR

  2. Check that 1/32 divergence slit is installed

  3. Mount sample on wafer stage

Setting up software

  1. In Data Collector software, under Instrument Settings, set 2theta, phi, psi, and offset (omega) to zero

  2. Under Instrument Settings, open any window. In the x-ray tab, set the generator power to 15 kV and 5 mA. XRR is done at lower power settings than XRD.

  3. Under Incident Beam Optics tab, open any window. Open Beam Attenuator. Set beam attenuator to "do not switch" and uncheck the "activated" check box. Usually MERTech has already done this, but it's worth checking.

  4. Under Incident Beam path in the Incident Beam Optics tab, make sure the divergence slit is set to slit fixed 1/32. MERTech often forgets this step.

Alignment

  1. Under Measure, Manual Scans, start a 2theta scan.

    1. Range: 2

    2. Step Size: 0.002

    3. Time/Step: 0.1

  2. Center peak. The counts at this step should be >200,000 cps. Write down the max count rate. Mine have been 750,000-840,000. Under User Setting, Sample Offsets, set 2theta to 0

  3. Set the z value of your sample between 8.9 mm. Start a z scan

    1. Range: 2

    2. Step Size: 0.001

    3. Time/Step: 0.1

  4. Using Move mode, move to position where cps is 1/10th of original value.

  5. Start omega scan

    1. Range: 3

    2. Step size: 0.01

    3. Time/Step: 0.1

  6. The peak for the omega scan should be broad and rectangular. Move so that the rectangle is centered. Record the counts

  7. Repeat alternating z and w scans until the maximum cps of the w scan is half of the original counts value of your initial 2theta scan (from step 9). This aligns the beam so that it is partially intersecting your sample, with sufficient reflection for the XRR measurement. The w peak will become narrower with successive scans.

Optimizing Reflected Intensity

  1. Write down the exact value of the offset. Under Instrument Settings, enter:

    1. 2theta: 1.7

    2. offset: value written down for offset

  2. Start a 2theta-omega scan

    1. Range: 3

    2. Step Size: 0.01

    3. Time/Step: 0.5

  3. Using Move mode, move the cursor to the maximum of the first clearly visible fringe. Distinctness of fringes seems to correlate with sharpness of layer interfaces in your sample. If fringes are not very clear, take your best guess. Switching to the log axis might help.

  4. Omega scan. Center peak

    1. Range: 1

    2. Step Size: 0.005

  5. Time/Step: 0.5

  6. Psi scan. Center Peak

    1. Range: 10

    2. Step Size: 0.1

    3. Time/Step: 0.5

  7. Omega Scan. Center Peak

    1. Range: 1

    2. Step Size: 0.005

  8. Time/Step: 0.5

  9. Write down the value shown for the offset. Under Instrument Settings, enter:

    1. 2theta: 3.7

    2. Offset: offset

  10. 2theta-Omega Scan. After scan finishes, use move mode to move the cursor slightly to the left of the critical angle (the angle at which the intensity of the curve starts to drop)

    1. Range: 7

    2. Step Size: 0.01

    3. Time/Step: 0.2

Adjusting Generator Settings

  1. XRR manual says check that cps is less than 800,000 cps. If so, proceed with scan with beam attenuator deactivated. If counts are much less than 800,000, increase generator power to 17-18 kV and 7-9 mA.

    1. If scanning very thin layers (< 6 nm), can be beneficial to run at higher power with the beam attenuator on- it can increase the resolution of long oscillation fringes. In this case, under Incident Beam Optics, Beam Attenuator, set the beam attenuator to "At pre-set intensity". Set activate level to 600,000 and de-activate to 400,000. Set generator power to 30 kV and 10 mA. This typically doesn't seem to be necessary- epitaxial layers typically have relatively distinct fringes.

XRR Scan

  1. Go to File, New program, absolute scan. Enter parameters for a 2theta-omega scan, and set the start and end angles. Choose 0.1 as the start angle- program gets confused by 0 as the start angle. 3-4 is a reasonable end angle. 5-10 seconds per step is reasonable for layers < 10 nm. Emily already has an XRR absolute scan set up appropriate for a single 6 - 30 nm layer.

  2. Go to file, save your program

  3. Select Measure, Program, choose your program and press ok.

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