cascade possibly not functioning properly

Soogine Chong sgchong at
Thu Nov 10 17:37:19 PST 2011

Hi all,  

I just used cascade and had some issues.  It could be a problem with my samples, but, just in case it's not, I thought it'd be helpful to share the issues I've had. 

The parameter analyzer was taking a very long time to measure small current levels, so I rebooted the system.  After rebooting, the overall current level dropped significantly, sometimes not showing any signal at all.  Also, the currents on the four probes, when all probing on the same Pt pad, didn't always add up to zero.  (It looks like the probes on the right side are showing higher current levels than the ones on the left.)

Possible reasons I can think of:
-I noticed that the substrate was biased to 3V using the LCR meter by the previous user.  Don't know how/why this could be an issue.
-I was probing on samples that had hardened PR removed with PRX-175.  It was the first time I tried this, so it is possible that there was some PR left on the pads.  Maybe the tips got coated with PR while probing?

I would be very interested in finding out how cascade works out for other users after me.  Do you see the same issues?


Soogine Chong
Stanford University
PhD candidate in Electrical Engineering
e-mail: sgchong at
mobile: +1-650-804-8556

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