Electron-beam-induced-current study of defects in GaN; experiments and simulation

A review is given of the prospects and limitations of the application of the electron-beam-induced-current (EBIC) technique in the study of the extended defects in GaN and related materials. The approaches commonly used for the analyses of the EBIC data are discussed. The profile of the dislocation EBIC contrast in materials with diffusion lengths smaller than the electron range is analysed. The simulation carried out shows that at small enough diffusion length values, the width of the dislocation contrast could decrease with increasing primary electron energy. It is demonstrated that in GaN structures the diffusion length can be estimated from the dislocation profile. The minimum defect cylinder radius which can be extracted from the EBIC measurements is evaluated. A pronounced dependence of threading dislocation EBIC contrast in n-GaN on the beam current is revealed, which could be caused by the dislocation charge.