Tutorial on Dynamic RDSon Test with FTI-1000

Dynamic RDSon Test : Key Requirements

  • Fast, Single Shot Measurement for good repeatability

  • Test is required to detect areas of wafer with highest trapping

  • Tester must tolerate bad DUT to avoid Probe Card failures

  • Fast Switching Time from OFF to ON State (need <1µs)

  • Fast Sampling to see Transients and Settling Time (need >20 MS/s)

  • Vds Stress Voltage needs:

    • Controlled Rise Time (no Overshoot)
    • Current must be Limited
    • Accurate Monitoring of Voltage and Leakage Current

  • < 1µs Measurement Delay after End Vstress and Start 2nd Rdson

    •  Minimize Stray Capacitance and Inductance

Dynamic RDSon Test Circuit

Dynamic RDSon Test Circuit
GaN Dynamic RDSon Test Method
Dynamic RDSon Test Method Stress
GaN Dynamic RDSon Test Method Stress
GaN Dynamic RDSon Waveform Before Stress
GaN RDSon after stress 5ms
GaN RDSon after Stress 5sec
GaN Dynamic RDSon Test Station

FAQ

Can Hard Switching Be Used?

Yes – add inductance in series with current sensor.

Agreed, but the worst case needs to be measured in a few μsec after stress, which is effectively the same measurement as Dynamic RDSon.

Trapping varies across the wafer, and so there is no other way to know if a specific die has higher RDSon

  • Measure time 10 µs (5 µs settling, 5 µs averaging), Stress Time 50 – 100
    msec for wafer sort.
  • It is possible to test faster, maybe as low as 1 µs settling and < 10 msec
    stress, for packaged part test.