Measuring gate leakage current

Farzad

Dear Support Team,

I am measuring the gate-source leakage current of the SiC MOSFET C3M0120065D in the lab, which according to the datasheet should be around 10nA. I have set up my experiment as shown in Fig. 1, using a Keysight B2902A Source/Measure Unit (SMU), which I have previously tested for linearity down to 1nA with resistive loads.

However, when I apply 15V to the gate and source of the SiC MOSFET, the current measured by the SMU is nearly zero, with significant fluctuations. My experimental setup is shown in Fig. 2. Could you please let me know if I might be doing something incorrectly while attempting to measure the gate leakage current?

Thanks.

Fig 1.png

Fig 2.png

Forum_Moderator

Thank you for your post, it has been approved and we will respond as soon as possible.

SGupta

Hello Farzad

Thanks for your patience. I’m not sure what the capabilities of this equipment are, if it’s able to measure that low as I see the measurement range is at 1uA on Figure 2.

Farzad

Hello @SGupta

Thanks for the reply! I have tested the accuracy of the measurement unit up to 1nA by using resistive load!

Can we say that the amount of gate leakage current written in the datasheet is quite conservative?

SGupta

Hello Farzad

In your measurement, is my understanding correct that you are getting a reading of 0.0033nA or 3.3pA? Further, is your equipment capable of measuring less than 1nA as well?

Farzad

Hello SGupta,

During my measurement, I faced significant fluctuations, with values sometimes appearing negative and at other times positive, though they generally remained in the picoampere range.

For currents less than 1nA, I need special cables for my measurement unit. At this time, I am unable to measure currents below 1nA. However, the datasheet for the SiC MOSFET mentions that the leakage current is around 10nA, which is why I chose this measurement unit.

SGupta

Hello Farzad

Thanks for expalining.

You are correct that values on the datasheet are very conservative and upon checking with the characterization team internally, I can confirm that the actual measured values of gate leakage current for this device are in 30~40pA range. That would explain the fluctuations you encountered in your measurements.

Let me know if you need further assistance.

Farzad

@SGupta Many thanks for your support and answers. I do not have any questions.

Best regards,

Farzad

SGupta

Thanks for your patience Farzad.