Relationship Between Nanotubes and Breakdown Voltage in GaN p–i–n Diodes

Abstract

The failure analysis of a GaN p–i–n diode is carried out by current–voltage (I–V) tests, emission microscope (EMMI), focused ion beam (FIB), and scanning electron microscope (SEM). A nanotube is found at the location of the luminous spot in the EMMI test. Intentional breakdown experiments show that the breakdown voltages of about 1/3 diodes with the size of are lower than 50 V. These proportions are 1/2 and 5/6 for the diodes with the size of and respectively. At the breakdown injuries of some diodes, the nanotubes are also discovered, which indicates that nanotubes should be one of the important reasons for the reduction of the breakdown threshold voltage.