I was trying to measure the leakage current of a small signal Schottky diode at 0.1V reverse bias and what I'm seeing doesn't make sense. I'm assuming it's a measurement anomaly and not reality, but I'm hoping someone can confirm that.
I measure around 11-13uA in the forward direction (ie. opposite of the applied voltage) when applying 0.1V. This current (shown as negative on the meter) goes down as I increase the voltage to around 3-3.5V, above which the current becomes positive and falls within the diode's specified leakage current as stated in the datasheet (max 2uA at 25V). I did the same test on another small signal Schottky model, a small signal standard diode and a larger current (5A) standard diode. All 3 of the small signal diodes showed the same behavior, only changing in the voltage threshold where the negative current becomes positive. The higher current diode showed the same positive leakage current at 0.1V that it did at 20V.
The current was tested with a Keithley 2000 meter which shows about 0.18uA noise measurement when not probing anything. I also tried testing the current by measuring the voltage across a resistor, using a 33.2k and then a 220 ohm, and all 3 methods show the same negative current at low applied voltage. I verified the applied voltage by connecting another meter to the probes. It reduced the negative current measurement, but verified that the applied voltage was correct.
So this negative leakage current (opposite of the applied voltage) must be just a measurement anomaly, right?
I measure around 11-13uA in the forward direction (ie. opposite of the applied voltage) when applying 0.1V. This current (shown as negative on the meter) goes down as I increase the voltage to around 3-3.5V, above which the current becomes positive and falls within the diode's specified leakage current as stated in the datasheet (max 2uA at 25V). I did the same test on another small signal Schottky model, a small signal standard diode and a larger current (5A) standard diode. All 3 of the small signal diodes showed the same behavior, only changing in the voltage threshold where the negative current becomes positive. The higher current diode showed the same positive leakage current at 0.1V that it did at 20V.
The current was tested with a Keithley 2000 meter which shows about 0.18uA noise measurement when not probing anything. I also tried testing the current by measuring the voltage across a resistor, using a 33.2k and then a 220 ohm, and all 3 methods show the same negative current at low applied voltage. I verified the applied voltage by connecting another meter to the probes. It reduced the negative current measurement, but verified that the applied voltage was correct.
So this negative leakage current (opposite of the applied voltage) must be just a measurement anomaly, right?