Reliability and trapping processes in GaN-based MOSCAPs with different atomic layer deposition (ALD) and pretreatment recipes.

In this thesis is reported the experimental analysis on charge trapping, interface states and reliability of aluminum oxide / gallium nitride MOS capacitors, produced with various pretreatments, oxide atomic layer deposition and post metallization annealing temperature (hereafter referred as recipes). The work is based on devices manufactured by Ferdinand Braun Institut under the framework of the YESvGaN European project. The first chapter is related to oxide trapping with various characterization methods, including analysis of the C-V characteristics the second chapter shows the investigation on reliability (with both current-voltage characterization to critical failure, stress test and time-dependent dielectric breakdown). It was shown that, based on these two topics, stacked layout and ammonia pretreatment provide the most reliable oxide. Finally, third chapter shows interface state analysis, investigated by photoassisted CVs, which points out that hydrogen pretreatment has a slightly better performances.