cascade possibly not functioning properly

J. Jason Lin jasonlin at
Thu Nov 10 17:42:45 PST 2011

Hi Soogine,

In case it's relevant, I also had some trouble probing Pt pads in the last
few days while probing Al pads was fine.  I would get very erratic I-V
curves that jumped up and down seemingly randomly and also very low
currents.  I pressed the probes down a little harder and that seemed to
solve the issues.


On Thu, Nov 10, 2011 at 5:37 PM, Soogine Chong <sgchong at> wrote:

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