Effect of deep levels and interface states on the minority carrier lifetime control of trench-IGBTs by electron irradiation

The relationship between the minority carrier lifetime and bulk defects and between this lifetime and the interface states due to 2 MeV electron irradiation were investigated using deep-level transient spectroscopy (DLTS) and the charge separation technique, respectively. There seems to be a correlation between the change in lifetime and the interface traps generated due to electron irradiation. For the same level of interface trap density after a fluence of 1x1014 e/cm2 electron irradiation due to Fowler-Nordheim (FN) high electric field stress, the lifetime did not changed. Due to the creation of a deeper state, which is probably a defect including V 2 and H with increasing electron fluence, the lifetime decreases further. It is thought that the Si-H bonds at the Si-SiO2 interface are broken and dissociated hydrogen is introduced in the silicon bulk during the electron irradiation