Evidence of minority carrier traps contribution in deep level transient spectroscopy measurement in n-GaN Schottky diode

It is shown that deep level transient spectroscopy can be carried out on Schottky diodes to investigate, in addition to majority carrier traps, minority carrier traps. This is possible thanks to the application of a large reverse bias to the device which allows minority carrier injection by lowering their corresponding effective Schottky barrier height. Indeed, when increasing the reverse bias voltage, the deep level transient spectroscopy signal, initially negative and thus showing only majority carrier traps signature, becomes positive, revealing minority carrier traps involvement. A careful analysis of the recorded spectra leads to the identification of four minority carrier traps which have been so far only evidenced using dedicated technique such as minority carrier transient spectroscopy.