I have used reverse recovery method for measurement of carrier lifetime. I have used a simple setup consisting of a function generator, a resistance and DUT (design under test). In a conventional transient response, there is a constant current phase and a recovery phase and effective carrier lifetime can be determined from these equations in the first link.
But transient response which I have measured, has not constant current phase and after switching, begins decaying to reverse saturation current. (second link)
My question is, why there is not constant current phase in transient response? Is it related to If/Ir ratio? Is there any consideration about If/Ir ratio in reverse recovery method?
Thank you.
https://www.tf.uni-kiel.de/matwis/amat/semi_en/kap_8/advanced/t8_1_1.html
https://i.stack.imgur.com/ohVy6.png
Hi Ali, did you try to increase the time during which the diode is in the forward condition?
I never tried it with diodes, but I know from experience with bipolar transistors that (within limits, of course) the constant current phase depends on the duration the transistor was held in the ON state before switching OFF. With general purpose transistors, the values given in datasheets are usually based on an ON-time >= 100 microseconds.
The qualitative explanation is that part of the internal structure of the device acts like an RC combination, so even if the device has reached the ON state (as seen from the outside) it takes some additional time to charge the internal C and to reach an internally stationary ON state, too.
Hope this helps.
Thank you Joerg Fricke. Excuse me for late reply. I changed (increased) If/Ir ratio and then a constant current phase appeared in reverse recovery curve. there are more details in the links below.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiYkdi-4OTUAhUJLFAKHWr4C5gQFgglMAA&url=http%3A%2F%2Flib.dr.iastate.edu%2Fcgi%2Fviewcontent.cgi%3Farticle%3D3293%26context%3Drtd&usg=AFQjCNFZYQsPPqgT_jFhaFaf4uRa13uwgg
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwj9xpjG4eTUAhXQb1AKHcL_BjkQFgglMAA&url=http%3A%2F%2Flib.dr.iastate.edu%2Fcgi%2Fviewcontent.cgi%3Farticle%3D3514%26context%3Drtd&usg=AFQjCNGfKGViCK9ZDaGMHtbLTxskAHijew
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