Frequently Asked Questions

  1. How to get lab access?
    Procedure to lab access can be found here.
  2. What are Do's and Don'ts of the lab?
    Do's and Dont's of lab can be found in the link :
  3. How can I get kicked out from the lab?
    Getting kicked out takes a fair amount of misdoings from your side. You can get kicked out in following circumstances
    1. Repeat offences of damaging instruments
    2. Using a system which you are not authorised to
    3. Disturbing/Damaging other users data/experiments in any way
  4. What measurement can be done in this lab?

    5. Slot Booking Related FAQs

  5. What is the maximum time I can book slot?
    Every instrument has slightly different slot booking rules. Complete set of rules can be found here.
  6. How early can I book the slot?
    Right now, slot can be booked 48 hours in advance.
  7. Why cannot I book the slots?
    Probable reason for not able to book the slots are
    1. You do not have the CEN Access : You can get it at http://www.cen.iitb.ac.in/slotbooking/
    2. You have not filled the google form which gives you the authority to book char lab slots. The link for the form is here
    3. If you are done with above two steps, contact a person named Mr. Anand (sits in Micro-e-office) and ask him to add your name to the char lab slot booking list.

    8. Measurement FAQs

  8. I was daydreaming while I was being trained. What steps should I take before starting the measurements?
    Following steps are necessary before starting any measurement
    1. Before loading wafer make sure you have switched on both the probe station power supply (Green button) and the vacuum pump
    2. Make sure the probes are sufficiently up so as not to damage your device when you lift up the chuck.
    3. Place your wafer on the chuck, press the vacuum on button situated near the chuck
    4. Probe the wafer and you are ready to go.
  9. My measurements are done, what should I do before leaving the lab?
    1. Make sure you have un-probed properly.
    2. Make sure you have switched off the vacuum pump, microscope light and the probe station power supply.
    3. Make sure you have made an entry in the log book
  10. It is really painful to always get up and close the lid (or door of black box) of the probe station. Is it really necessary?
    The black box/ lid for the probe stations act as a Faraday cage and do not allow electromagnetic noises to enter the probe station. So even it is very painful it is always necessary to close the lid or the door of the probe station before doing measurements.

    11. Probing/Unprobing Related FAQs

  11. What precautions should I take while handling manipulators?
    First thing first, never handle manipulators without switching on the vacuum and probe station power supply.
    Now to answer this question, we need to understand how manipulators work. It basically consists of three screw-gauges, each moving the probe arm in x,y & z direction. As with any screw gauge you should be very careful how much you are screwing in or screwing out. There are limits to each and one should respect that.
    Lastly, do not move the manipulator further once it is probed, it will surely damage the probe tips.
  12. Why can I not keep the device probed while increasing or reducing the temperature
    As with any metallic surface (chuck in this case), it contracts or expands when you increase/decrease the temperature and hence your wafer can move around with chuck's expansion and contraction and hence damage both the probes and your device.
    So as a precaution do not probe the device atleast 10mins after you have increased or decreased the temperature.
  13. I have an awesome 6/6 vision, can I do probing without looking through microscope?
    Probing should always be done with the device properly focussed under the microscope, and under no circumstances can the probing be done without looking through microscope.
  14. My contacts are very far away. They do not fit in the focus area of the microscope. Still can't I probe without a microscope?
    In these cases always consult the lab RAs, they will help you out. The procedure is for probing in such cases is:
    1. Decrease the zoom of the microscope (If using at 10X change the lens to 2X), this can be done by rotating the lens switcher.
    2. If still you cannot see all your contacts, focus to a particular contact, probe that contact, now move the microscope (not the chuck) in x or y direction using the knobs at the bottom right base of the microscope and focus on your other contact. Now probe the other contact. Repeat this procedure for all the contacts.
    Be extremely careful while probing in such cases, there is high probability that the manupulator and/or tips may get damaged if you are not.

    15. Troubleshooting FAQs

  15. The instrument is not giving any current. What am I doing wrong?
    There can be many reasons for which instrument might not be giving a proper current
    1. Check switch matrix connections if you have made correct connections. This is the most common mistake done by users. Recheck which SMU and manipulator combinations.
    2. Check whether the device is probed properly.
    3. Check if you are giving proper voltages values
    4. Check with a previous device which you know worked.
    5. If nothing works out, kindly contact RAs
  16. The probe tip is bent or damaged. What should I do?
    Kindly contact RAs and ask them to change the tip
  17. How to perform the open and short corrections?
    Detailed instructions of open and short corrections can be found in the CV fundamentals section (link) and also in the procedure
  18. What is the specification of the instrument?
    Specifications of each instrument is provided in the setup pages. Kindly use the menu in the left sidebar.
  19. What is the range in which an SMU can measure voltage and current?
    Specifications of each instrument is provided in the setup pages. Kindly use the menu in the left sidebar.