12.13 Final.2025

Abstract
Dislocation of GaN epi has a strong correlation with reliability and electronic property of a GaN pHemt device. From technology development and field experience, dislocation under a device could cause possible reliability failure especially HTRB. In failure analysis for GaN dislocation, two beam condition of TEM is a common method, but the limitation of sample dimension and high cost are its disadvantages. In the literature, top-view observation by OM/SEM for etched epi by acid/base could be a reliable method for dislocation identification and density calculation[1][2][3]. By a series of experiments, we have developed an etching method by using molten KOH to obtain top-view SEM images of etched GaN epi and their correlation between defect density and reliability/electrical performance.