The　effects　of　reverse　pulse　electrical　stress　on　the　electrical　and　trapping　properties　of　Depletion-Mode　(D-Mode)　GaN　high-electron-mobility　transistors　(HEMTs)　are　investigated　in　this　paper.　The　results　of　HEMT　testing　show　that　the　device’s　electrical　characteristics　in　the　OFF-state　are　degraded　after　reverse　pulse　electrical　stress　cycling,　along　with　the　gate-to-source　reverse　current　and　drain-to-source　leakage　current　characteristics.　In　particular,　three　traps　in　the　device　are　identified　using　the　voltage-transient　method,　and　the　trapping　effects　in　the　HEMT　are　investigated　after　70000　pulses　of　gate　reverse　electrical　stress　are　applied.　The　sources　of　the　traps　identified　in　the　study　include　interface　traps　near　the　surface　of　AlGaN　or　at　the　SiN　interface　(DP1),　intrinsic　defects　such　as　N　antisites　in　the　GaN　buffer　(DP2),　and　traps　in　the　gate-drain　access　region　(DP3).　Comparison　with　the　transient　voltage　characteristics　of　the　original　device　shows　that　the　absolute　amplitudes　of　the　traps　in　the　device　increase　after　application　of　the　electrical　stress,　thus　indicating　an　increment　in　the　trap　density.　It　was　found　that　DP1　remained　unchanged　before　and　after　stress　application,　which　may　be　the　result　of　an　inadequate　surface　passivation　process.　With　regard　to　the　other　two　traps,　the　electrical　stress　increases　the　trap　density　of　DP2　and　causes　the　emergence　of　DP3　as　one　new　trap.　These　results　may　be　useful　in　the　design　and　application　of　AlGaN/GaN　HEMTs.　These　results　may　be　useful　in　the　design　and　application　of　AlGaN/GaN　HEMTs.　IEEE