Haewon Uhm

Haewon's weekly updates for the ALD and SOG.

Update 1

Accomplishments

• Completed the project proposal and went over it with the TAs

• Set up the reflux apparatus in the acid fume hood (SOG)

• Decided to start with replicating the ProjectsInFlight formulation with later tests of catalysts, altering the ratios of ethanol, phosphoric acid, and boric acid (SOG)

• Learned in greater detail the systems involved with the ALD controls (ALD)

Challenges

• Still having trouble downloading LabVIEW onto my computer

• Will probably need assistance from Viswesh

Issue that comes up when trying to download LabVIEW multiple times.

Future Plans

• Solidify the plans for SOG and get more acclimated to the lab overall

• Do more research on the chemicals involved, narrowing down the many possibilities of failure (especially the boric acid)

• Download LabVIEW and start learning how to use the system

• Gain access to the LabVIEW for the ALD

Update 2 (SOG)

Accomplishments

• Ordered 95% ethanol that is needed to replicate the ProjectsInFlight formula

• To start testing, decided to use isopropyl alcohol as an ethanol replacement

• Looked into the Filmtronics ingredient list for 700B and found it possible to test ratios in the future

Challenges

• Realized we did not order ethanol, which is a key ingredient in the ProjectsInFlight video, so I have to wait until that comes in

• Already resolved with Jay and Daniel

Future Plans

• Start testing the formulation of the n-doped spin-on glass using TEOS or TMOS, water, isopropyl alcohol, and phosphoric acid (ratios based on the video)

• Might not work due to the less polar nature of IPA than ethanol and therefore not provide the emulsification that is needed for the water and TEOS/TMOS

Update 2 (ALD)

Accomplishments

• Got more adapted to LabVIEW and was introduced to the ALD valve and heating element control systems on my computer

• Used a YouTube video to try and connect the MC DAQ to LabVIEW directly

Challenges

• Couldn't directly download the LabVIEW file from the GitHub due to the different version that is available for Mac versus Windows

• Resolved with Viswesh

Future Plans

• Continue to try and connect the MCC DAQ to LabVIEW

• If that does not work, make Python code that will alternatively do the job

Update 3 (SOG)

Accomplishments

• Tested the ProjectsInFlight recipe with the exclusion of ethanol in place of IPA.

• Procedure can be found under 2/5/25 in the following doc: https://docs.google.com/document/d/1Zv89gYlrvVO8jFVvS3HTmG_rJBMBwB7pDHd5lRpelhI/edit?tab=t.0

Formula of the recipe tested.

Challenges

• After the heating, there was a residue inside the flask even after thoroughly washing (assuming it is glass).

• The solution did not evaporate into the reflux apparatus and condensate back in to the flask at all (only condensate within the flask).

• Our dopant on a chip was visibly darker in complexion in comparison to the commercial dopant on a chip.

• More striations were present in the DIY SOG (not as smooth and might be due to the replacment of ethanol with IPA).

Shows the solution only condensing within the flask.

Shows the residue that was present after cleaning the flask.

Future Plans

• In the video, there is somewhat direct heat contact between the flask and the hot plate without the use of a water bath, so higher contact temperature with the flask for a shorter amount of time should be tested with the same recipe from 2/5/25.

• Research a type of silicate polymer that is compatible with the other ingredients shown below, and add that, along with reagent alcohol, to the purchase tracker.

Ingredient list on the Filmtornics website for 700B.

• Vary the amount of 85% phosphoric acid by adding and subtracting 0.25 mL from the original 0.5 mL.

Update 3 (ALD)

Accomplishments

• Found a way to connect the MCC DAQ to LabVIEW using InstaCal and ULx through this link: https://files.digilent.com/manuals/QS%20ULx%20for%20NI%20LabVIEW.pdf?_gl=1*1oftj18*_ga*MTU3NzI5NjAxMy4xNzM4NTcxMDcz*_ga_YFKL15TK2S*MTczODU3MTA3Mi4xLjAuMTczODU3MTA3Mi42MC4wLjA

• Instead of using the MCC DAQ to control the heating elements, relay hats and thermocouple breakouts will be connected to a Raspberry Pi 4 and the heating elements.

Control system diagram.

• Connected the Pi 4 and tested the thermocouple relays with the python library and code provided by the adafruit: https://learn.adafruit.com/thermocouple/python-circuitpython

• Looked over the manual for the throttle valve software: https://www.idealvac.com/files/manuals/CommandValve_Generation_II_User_Manual.p

  • DirectVac software only runs on windows

  • Open and close fully or open incrementally by 1º

  • Any device capable of running a USB host and can communicate serial commands can precisely operate the CommandValve

Challenges

• InstaCal and ULx only run on Windows, so I could not check it myself, but also later found out that LabVIEW is not compatible with the MCC DAQ, so we needed to find a new way.

• Decided to scratch the use of a MCC DAQ as a whole.

Future Plans

• Look into how to run both ALD valves and the PID temperature LabVIEWs simultaneously once LabVIEW is downloaded onto the mini PC

• Find the python block on LabVIEW and see if the python script runs on LabVIEW

• Make python code that cycles through the thermocouples and averages the temperatures outputted, sending only one averaged value to LabVIEW

• Need to transfer the temperature readings from the Pi 4 to a mini pc that is running LabVIEW (Pi 4 is quite slow).

• Learn more about the adafruit library and code to accomplish the main task.

Update 4 (SOG)

Accomplishments

• Tested the ProjectsInFlight recipe with the exclusion of ethanol in place of IPA.

  • Recipes for each test can be found in the following doc: https://docs.google.com/spreadsheets/d/11cc8vFxX2Cdq87uaElUpQxJZl3V7WWIpoaZI9dVXeNA/edit?gid=0#gid=0

• Direct heat of 175ºC for 30 minutes on 2/13/25.

Before diffusing

After diffusing

• Direct heat of 100ºC for 15 minutes on 2/14/25.

Before diffusing

After diffusing

• Diffused the first sample made on 2/5/25.

Before diffusing

After diffusing

Roadblocks

• No stir bar was used on 2/13/25 and might have been the reason for excessive residue at the bottom of the flask (need to order).

Residue left at the bottom of flask

• There was a good amount of residue at the bottom of the flask that turned into a crystal-like powder after being left out in the flask for one day.

  • The silica solid residue collapsed due to the dehydration of the solvent since it was left out (DI water and IPA).

• Still not reaching the reflux apparatus (might be too little liquid for the size of the flask and the reflux apparatus).

  • This shouldn't be an issue since there is condensation visible within the flask.

• The leftover solution from the first sample (2/5/25) solidified into a gel consistency after a week in its container.

  • The SOG is not sustainable and has a short shelf life, which might be due to the speed of the reaction.

Future Plans

• Continue to test the temperature and time

  • Direct heat of 100ºC for 25 minutes.

• Since I could not get to it last week, vary the amount of 85% phosphoric acid by adding and subtracting 0.25 mL from the original 0.5 mL.

  • Increasing the phosphoric acid increases viscosity, and decreasing is okay as long as the pH is within the range that minimizes the reaction speed or else the shelf life of the dopant will tank (pH of 3-4)

• HF etch the previous chips and test the conductivity using the probe station.

  • Look into how you know the dopant is successful and the range of all the components.

• Grasp a better understanding of why the results are turning out the way they did, especially the test from 2/13/25

Update 4 (ALD)

Accomplishments

• Found the python node on LabView.

  • Functions palette, connectivity, python.

Python node on LabVIEW

• Instead of working and testing the python code all at once, I focused on writing the code to average the temperatures read from one thermocouple on the Raspberry Pi.

  

  Python script added to the Raspberry Pi
• Able to run multiple VIs through a primary VI by calling multiple subVIs through the primary VIs:

  • https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000YHyLCAW&l=en-US (use to get started in the future).

  • https://forums.ni.com/t5/LabVIEW/How-do-I-run-2-or-more-VIs-simultaneously/td-p/276636 (helpful if there are issues).

Roadblocks

• Could not run the python script on LabView since it is incomplete.

  • With the absence of a mini PC, would it be reasonable to figure out how to run the script through the PI instead of from the mini PC?

• Had difficulty analyzing whether the code was averaging different temperatures due to the fact that the same number was repeatedly being outputted

  • Would it be possible to check with a wider range of temperatures to see if the output changes in that case?

Future Plans

• Confirm whether my python script is averaging the temperatures correctly.

  • Could attempt to make a list of random values to average, importing the random library to do so.

• With the use of serial ports, run the python script on more than one thermocouple breakout.

• Work on the section of the main function code where the data will be sent.

Format of the main function

Update 5 (SOG)

Accomplishments

• Tested the resistivity of chips 637 and 639 (got rid of 640)

  • 637: around 20 ohms

  • 639: around 25 ohms

• Replaced the tubing for the water supply that reaches the drain

• https://webbut.unitbv.ro/index.php/Series_I/article/view/6140/4712

  • Increasing TEOS concentration will increase viscosity

  • If the particles grow too large, precipitation takes places

  • The time of gelation decreases for low water ratio

  • Heating at relatively high temperatures (100-500ºC) will accelerate the hydrolysis and condensation, removes the organic species, and forms SiO2 bonds

Roadblocks

• Didn’t have a sample with the commercial SOG

• Does the precipitate that is formed actually impact anything

Future Plans

• Characterize and compare whether the resistivity is in the general range of a commercial SOG

  • Make a chip sample with P504

• Try the p-doped SOG using boric acid

• Do more research on sol gel components

Feedback

• important distinction - what we measured on the chips is corner-to-corner surface resistance, which is not very consistent. We want to do a proper resistivity test using resistor patterns to properly measure it with the probe station

• The source on sol-gel is interesting- if we can better understand how to avoid the residue that would be great 👍
• I think all the chemicals we'll need are here! let's make more samples to test :)

— Daniel

Update 5 (ALD)

Accomplishments

• Found out how to localize the python on the Raspberry Pi

  • https://roboticsbackend.com/raspberry-pi-run-python-script-in-the-terminal/#Run_Python_code_directly_on_the_terminal

  • Using a nano terminal

  • Need to localize on the PC since LabVIEW can't connect to the Pi directly

• Integrated the thermocouple DAQ onto the physical Pi

• Tested the code to test the thermocouple DAQ but threading is not needed

Roadblocks

• Still working on LabVIEW connection

Future Plans

• Using the new libraries for the thermocouple DAQ, make a new code that will average the data and send to LabVIEW

  • Replace the libraries that are for the thermocouple DAQ

  • Multiple thermocouple connections

• LabVIEW connection

  • Return value: https://forums.ni.com/t5/LabVIEW/Specifying-Return-Type-for-Python-Node/td-p/3932556

    • Resolved issue from NI for the return value

    • Control of type double

  • Module block:

    • Test a sample code on the local PC and run on LabVIEW

  • Look into SSH commands

    • https://bitbucket.org/ChrisCilino/raspberry-pi/src/master/

Update 6 (SOG)

Accomplishments

• Tested the recipe for p-doped SOG

• Made an n-doped control using P504

Roadblocks

• Residue on the chip after annealing the chip on the hot plate for 15 mins at 350ºC

  • If the ratio of vitrifying agent to boric acid is greater than about 2 to 1, a crystalline residue is formed upon drying: https://patents.google.com/patent/US20080305351A1/en#:~:text=Generally%2C%20if%20the%20vitrifying%20agent,drying%20of%20the%20aqueous%20mixture.

Future Plans

• Pattern previous chips and test resistivity properly with the probe station

• Manipulate the p-doped recipe to prevent the crystallization and formation of boric acid residue

Ratios of moles of amino/methyl/propanol to moles of boric acid

• Try the 700B concentrations from the Filmtronics SDS

Update 6 (ALD)

Accomplishments

• Locally connected a “Hello, World!” python code to LabVIEW

Dummy test for the LabVIEW connection

• Integrated the new library for the thermocouple DAQ into the python script

  • Calls a specific channel (1 or 2) to initiate averaging temperatures continuously

    

    Integrated into previous python code

    

    Attempted to alter for multiple thermocouples
• SSH commands are not necessary since we are calling the python script to LabVIEW from the mini PC locally

Roadblocks

• Have to discuss how we will call a specific channel of the four channels that will be used through LabVIEW and python script (string, boolean, integer)

  • All four channels simultaneously?

  • Continuous loop or stop at a certain point?

• Question whether a main function is still necessary

Future Plans

• Make a python script that can be called from LabVIEW based on a certain channel based on discussion

• Use multiple thermocouples and test the python script

Update 7 (SOG)

Accomplishments

• Discussed possible changes to the project

  • Concentration of phosphoric acid should be diluted but causes an imbalance in pH (not acidic enough, but nitric and sulfuric acid might be too risky to use in lab)

  • P-dopant is not acidic enough but same issue as mentioned above

  • Trimethyl borate in replacement of boric acid had better results according to the comments of the ProjectsInFlight video

• Annealed p-type chip and P504 (P504 turned out very bad, have to redo)

P504 post-diffusing

P-type post-diffusing

Roadblocks

• Couldn't thermally evaporate or pattern in order to probe the chips properly for the resistivity

  • Hopefully fixed for the next week

  • Preventing us from moving forward with testing P-type and N-type due to the uncertainty in concentration and pH

Future Plans

• Start testing the 700B recipe since all the chemicals came in

• Probe all the chips and calculate resistivity and dopant concentration

• Remake controls (P504, B152, and 700B)

Update 7 (ALD)

Accomplishments

• Discussed changes for the Python script (updated to Github)

  • Change back to a running average

  • Return a new value every five seconds (still appending new values every one second)

  • Four inputs and four outputs

• Created a LabVIEW to test the Python script with four channels involved

LabVIEW to test the new script

Roadblocks

• Unsure if the script will run smoothly based on the LabVIEW

  • Will test as soon as possible

• The Python node includes a return value and type, but there might be complications on whether LabVIEW can differentiate the four return values

  • Using a cluster on LabVIEW might not be the best or have to make the script more specific to LabVIEW

Future Plans

• Test the LabVIEW

  • Research and make changes based on the results

• Discuss with Viswesh and Joel about the next steps for controls

Update 8 (SOG)

Accomplishments

• Attempted to pattern and probe four of the test chips, but it was unsuccessful and currently in the process of re-patterning and probing

• Spun on P504 and B154 onto new chips to start the process of making the controls for the project

Roadblocks

• Over etched the aluminum on the chips, so had to etch everything off and start again

  • Just finished the Al evaporation

  • Scratched one of the chips pretty badly trying to take it off the thermal evaporator

• Couldn't start testing the 700B recipe from Filmtronics (thought it would be better to finish testing the previous chips and make the controls for the project)

Future Plans

• Finish the P504 and B154 control chips and start the 700B control chip

• Continue to pattern and probe the four chips

• Possibly start testing the 700B recipe!!

Update 8 (ALD)

Accomplishments

• Changed the python script to return a list instead of four separate values (updated to Github)

  • Easier for LabVIEW

• Replacing the Raspberry Pi 4 and thermocouple DAQ with Arduinos, MAX31855 thermocouples, and a relay shield to simplify the control system

Roadblocks

• The Raspberry Pi wasn't being responsive on Real VNC

  • The 3.3V supply failed and therefore was not allowing the device to boot

• Thermocouple DAQ was making a weird sound that it has not made before

• Arduino IDE runs in C/C++

  • Have to convert the Python Script or use an indirect application

  • Cannot use the Python node on LabVIEW anymore since we need to read the thermocouple temperatures from a serial port

Future Plans

• Look into Arduinos and how they will work within the controls

• Discuss with Viswesh and Joel what to do with the Python script from here and make changes based on that

• Research how to read into a serial port from LabVIEW