Cross-sectional SEM-EBIC analysis of semi-vertical GaN power diodes

Electron beam induced current (EBIC) technique has been used to study depletion regions at the cross-sections of semi-vertical Gallium Nitride (GaN) p-n-and n: -p-n- diode structures. It has been successfully used to visualize the space charge region (SCR) at the p-n- junction and its widening into the n- drift layer, which allowed to reveal dark lines with discernibly vertical orientation assigned to threading dislocations (TDs). In these devices, also EBIC inhomogeneities at the top n + /p-body junction have been detected. Proper formation of the lateral isolation by Nitrogen implantation has been proved by a sharp drop in the EBIC signal at the border between the active and the N-implanted areas.