Nuclear microprobe investigation of the effects of ionization and displacement damage in vertical, high voltage GaN diodes

The Effect of Radiation Damage on the Charge Collection Efficiency of Silicon Avalanche Photodiodes

“…The measurements also showed that the time duration of the IBIC signal remained the same regardless of bias, suggesting that SCR widening was not a contributing factor to DECM. Since TCAD simulations showed that the carrier drift velocities remained constant, the SCR could not have widened without also increasing the carrier transit times [14]. While SCR widening seems an unlikely culprit, it was not possible to say if DECM was merely caused by an increase in electric field due to the creation of new space charge.…”

“…This device has exhibited an 8-fold increase in CCE following irradiation with silicon ions. Vizkelethy has in turn proposed that the defects themselves were assisting in the process of impact ionization [14]. This process is better known as trap-to-band impact ionization (T2B-II) and it has received a thorough theoretical examination by Robbins in the early 1980's.…”

“…It is similar in concept to B2B-II except that only one additional carrier is freed instead of two, and the energy threshold is lower than the semiconductor band gap [15][16][17]. It is not clear what ultimately causes DECM except that it appears related to impact ionization [14].…”

Degradation of vertical GaN diodes during proton and xenon-ion irradiation

“…2(b). The plotted values include the current transition of GaN highelectron mobility transistors (HEMTs), [27][28][29][30] the current transition of the GaN PND, 31) and intensity transition of GaN LEDs. 32) The measured current during the proton irradiations should be higher than the current after the proton irradiation and cooling because the measured current includes the carriers generated by radioactivated surrounding objects and thermal agitation.…”

“…32) This smaller degradation may have resulted from the formation of complexes between the proton-induced defects and donor/acceptor dopants in the GaN LED and PND. [27][28][29][30][31][32] We need to conduct further investigations to elucidate the relation between the degradation and the structure of GaN devices.…”