Tektronix Technical Forums are maintained by community involvement. Feel free to post questions or respond to questions by other members. Should you require a time-sensitive answer, please contact your local Tektronix support center here.

Measuring inductance with Keithley 4200 SCS+CVU

Post Reply
melrizou
Posts: 2
Joined: February 15th, 2016, 3:27 am
Country: United Kingdom

Measuring inductance with Keithley 4200 SCS+CVU

Post by melrizou » February 15th, 2016, 3:40 am

Hello,

I am using Keithley semiconductor characterization system 4200 with CVU module and I am measuring the impedance along with the frequency of fabricated semiconductor micro-inductors. I finally want to extract the inductance of the micro-coils which is estimated to be in the range of nH.
In my attempt to improve the accuracy of my measurements I calibrate the CVUs by performing the open and short corrections. Also I use the confidence check before the open and short corrections and I receive a warning which I believe affects the open correction. The warning during the open confidence check says:"HI side source and sense cables appear to be heavily loaded!" and "LO side source and sense cables appear to be heavily loaded!". The short correction confidence check seems to be ok.
The results after applying both corrections are strange. I even receive negative resistance!
Do you have any idea why this is happening and how I could improve the measuring accuracy? Besides that, is the equipment capable of measuring so small inductances (I believe yes especially in the high frequency range)? If not, what equipment do you suggest for this type of measurements?
Also:
I haven't tried to connect the shields of the two probes. Is this important for frequencies up to 10MHz? Do you believe I need any type of specific needles? Finally for your information I use two probe measurements.
Any help will be much appreciated. Thank you!

Andrea C
Keithley Applications
Keithley Applications
Posts: 1262
Joined: October 15th, 2010, 10:35 am
Country: United States
Contact:

Re: Measuring inductance with Keithley 4200 SCS+CVU

Post by Andrea C » February 15th, 2016, 7:36 am

I've uploaded a brief app note on using the formulator together with the Z and theta measure model to compute Inductance from the 4210-CVU card.
4200Indctn_AppNt.pdf
Compute Inductance App Note
(148.78 KiB) Downloaded 1136 times
Connection of the shields close to the DUT (at your probes) is advised to reduce loop area and give you a better high freq return path.

melrizou
Posts: 2
Joined: February 15th, 2016, 3:27 am
Country: United Kingdom

Re: Measuring inductance with Keithley 4200 SCS+CVU

Post by melrizou » February 15th, 2016, 10:56 am

Hello again,
Thank you for the feedback! I am aware of this document and actually this is what put me into thoughts about the capability of the equipment to measure inductances in the range of nH. However an inductance in the range of nH, at 1MHz, corresponds to a reactance X vector of approximately 10^-3. In that frequency the resistance vector R is approximately 10. Does this difference of 3 orders of magnitude make the measurement imposible?
Also do you know what could be the reason of the warning I receive?

Post Reply

Return to “Nanotechnology Measurements”

Who is online

Users browsing this forum: No registered users and 2 guests