Rigaku XRD
Background
Training
Shadow other LASE members before continuing with the rest of the XRD training below. New users must complete the following items before they are given system access to perform XRD.
Before the formal on-site XRD training can take place, new users must complete UT's radiation safety training course, OH 306. This course is 3-hours long and is given monthly on Main Campus. New users can sign up for this course through UT's course training network.
Reading
Training manuals? Meredith's slides?
Recent History
The Rigaku XRD was installed in Fall 2017, to replace the previously used Philips XRD due to the gradual degradation of the Philips' stage motor control and ability to continuously measure counts for the length of time required to complete a scan.
Unlike the Philips XRD, the Rigaku has the capability to perform both XRD and XRR measurements without changing the hardware, as well as pole figures, RSMs, and in-plane measurements. The alignment procedure is also significantly more automated.
The Rigaku currently requires 1 hour of aging prior to beginning a scan - this can be controlled with a timer.
I strongly recommend emphasizing to XRD users from other groups that we are happy to help or answer general use questions if they run into a problem with their measurement. We do not want a repeat of the Philips issues. - ESW
Contacts
Meredith Shi - SmartLab training, Meredith.Shi@rigaku.com
Others?
Set Up Procedure (for XRR and XRD measurement)
The default hardware setup for the Rigaku is shown below. If you change the hardware for your measurement, return it to this configuration when you are finished
Note that the 5 degree Solar Slit / RPS adapter is installed on the detector (right) side
The divergence slit labeled "10" on the source (left) side can be changed depending on the sample size. Divergence slits are in toolbox inside XRD. You will be prompted to install the appropriate slit size when you begin your measurement
The sample holder (top plate) and spacer (below) are both installed here. They are two separate pieces.
At the computer, open the Rigaku Smartlab Guidance application window. Login with your account name and password.
Begin the aging process (at least 70 minutes in advance)
Press Startup to bring up aging process window
Hit execute (or set a timer if needed)
XRD will ramp up to normal operating conditions (45 kV / 200 mA)
Confirm correct setting in hardware window in bottom left of Rigaku window
After aging completes, load sample
Log into labaccess
Press door lock on outside of XRD
Beeping will start and doors will unlock (doors will not unlock if you are not logged in on labaccess)
Load sample on crosshair on center of stage. Use magnets to hold sample if you expect significant tilting during your measurement.
Regardless, make sure the magnets are not blocking the path of the beam to your sample
Close doors and press door lock to lock doors
Beeping should stop
Select appropriate measurement from the User defined package list on the right hand side of the screen - the procedures for each are listed below
Only select measurements from the user defined package list, unless you have been specifically trained in the other measurement by another lase member
Other measurements require reconfiguration of the XRD system, which must be performed by the facilities staff or a specifically trained user
After measurement completes
From User Defined menu on right, choose Shut Down
Click Move button on flow chart to move XRD back to idle position
Press door lock button on outside of XRD
Beeping will start and doors will unlock
Unload sample
Close doors and press door lock button to lock doors
Make sure XRD is back in original hardware configuration if changed. Running an optical alignment may be necessary after replacing hardware following an RSM.
Check that other users do not need the XRD left on in order to prevent having to re-run aging process
If no other users, choose Shutdown from top left menu and click execute. XRD will power down to idle settings (20 kV / 10 mA)
Log out of the Rigaku software and logmein
Scheduling Tube Turn on
The tube can be set to turn on at a specific time.
Click on Startup..., as with normal tube turn-on.
Check the Timer box
Select a Start or End time configuration
Set a date and time at which the tube turn-on should start or end
Press OK (rather than Execute)
The up arrow in the Startup... button should now have turned red
XRD "Rocking Curve" Procedure
This procedure is for a coupled omega-2theta scan, which at MER is referred to as a "rocking curve". We typically use this measurement to determine the crystalline orientation of our epitaxial films, and how well they are lattice matched to the substrate. The thickness may also be determined from interference fringes in sufficiently thick/smooth films.
Outside of MER, the term "rocking curve" is used to refer to an omega scan where the sample is tilted, in order to determine the texture of a polycrystalline sample
I strongly recommend not referring to this scan as a rocking curve outside of MER, particularly at job interviews
The data generated from this measurement is in terms of 2theta-omega. Our group standard is to plot XRD in omega-2theta, so make sure to convert before presenting data.
Sample Alignment
Choose "MER Rocking Curve HR-PB Ge(220x2)" from User Defined list
Click Sample Alignment Button on flow chart (left menu)
Set sample thickness, width, and height. These do not need to be very precise, unless your sample is very small (< 1 cm on at least one side, i.e. transferred Bi samples)
Hit Execute
You may be prompted to change the divergence slit
You should not need to change the hardware, if prompted to do so check that current hardware setup and package selected are correct.
Profile window will pop up showing alignment steps
Takes approximately 10-15 minutes
Note- there is no notification when the alignment finishes- the window saying "executing measurement" disappears when the alignment is complete.
Rocking Curve Pre-Measurement (aligns to substrate peak)
From the top menu, choose Process --> Crystal Information
Select appropriate substrate
From the top menu again, choose Process --> Diffraction space simulation
Choose the appropriate hkl value from the simulation for your substrate
Confirm that the hkl value in the bottom of the right menu and the 2theta / w angles in the top of the right menu match your selection
Click move gonio near the top of the right menu to move the XRD to the appropriate position for your hkl value
Click Rocking Curve Pre-Measurement on flow chart (left menu)
Set up location to save your file
Make sure Move Origin is checked
Under Move Origin, choose Read Current Positions to input the positions for your selected hkl value
Click Execute
The profile window will show pre-alignment steps. This step takes approximately 15 - 20 minutes.
Rocking Curve Measurement (acquires the data for the actual measurement)
After the rocking curve pre-measurement completes, click "Rocking Curve Measurement" on flow chart
Set up file save location
Make sure omega scan is unchecked, and 2theta-omega scan is checked
Set the measurement range, step size and speed appropriate for your sample
You can choose to use either a relative range (values entered are with respect to the current position, aka the substrate peak), or an absolute range (values are beginning and end of 2theta range measured). An absolute range may be easier to calculate for wider scans.
Click "Execute"
Wait for scan to complete
Finishing Measurement
Unload sample following procedure in first section
XRR Procedure
XRR is used primarily to measure the thickness of thin films, and to determine the roughness or density.
In order for XRR to be successful, the film must be relatively smooth
The Rigaku XRR can measure films as thin as 4 nm, and possibly thinner
Here is an example of XRR of smooth vs rough ~ 8 nm Bi films (the sample grown at 35 degrees is rougher)
Sample Alignment
Choose MER Reflectivity (XRR) HR PB-Ge(220)x2 from the User Defined list on the right hand menu
Click Sample Alignment on the flowchart (left menu)
Set sample thickness, width, and height. These do not need to be very precise, unless your sample is very small (< 1 cm on at least one side, i.e. transferred Bi samples)
Hit Execute
You may be prompted to change the divergence slit
You should not need to change the hardware, if prompted to do so check that current hardware setup and package selected are correct.
Profile window will pop up showing alignment steps
Takes approximately 10-15 minutes
Note- there is no notification when the alignment finishes- the window saying "executing measurement" disappears when the alignment is complete.
Reflectivity Measurement
XRR is insensitive to the orientation/type of your substrate
Click Reflectivity Measurement on flowchart (left menu)
Set up location to save file
Choose Custom Conditions and make sure that PSA no_unit is selected on the detector side
This step is very important- otherwise the software will prompt you to change the hardware, which is not necessary
Select appropriate range. A range of 4 degrees works for most samples. A range of 6-8 degrees is necessary for very thin samples (<8 nm)
Click"Execute"
Pre-measurement and measurement run simultaneously - take ~ 15 minutes.
Finishing Measurement
Unload sample following procedure in first section