In　this　paper,　the　carrier　trapping　behavior　and　electrical　characteristics　of　AlGaN/GaN　high　electron　mobility　transistors　(HEMTs)　under　different　bias　conditions　are　studied　based　on　the　transient　current.　By　considering　the　transient　drain　current　of　HEMTs　at　different　temperatures,　three　trapping　mechanisms　are　identified:　(1)　charge　trapping　in　the　AlGaN　barrier　layer,　in　the　gate-drain　region　near　the　two-dimensional　electron　gas　(2DEG)　channel;　(2)　charge　trapping　in　the　GaN　layer,　in　the　gate-drain　region　near　the　gate;　and　(3)　charge　trapping　on　the　surface　of　the　AlGaN　layer,　in　the　gate-drain　region　near　the　gate.　The　influences　of　the　source-gate　and　drain-gate　voltages　on　trapping　behavior　are　analyzed　to　further　elucidate　the　trap　locations.　The　experimental　results　show　that　charge　capture　is　mainly　affected　by　the　drain-gate　voltage.　High　electric　field　stress　affects　the　local　structure　order　inside　the　device,　thus　affecting　the　charge　escape　rate.　The　threshold　voltage　shift　is　mainly　affected　by　the　surface　trap　of　the　AlGaN　layer　near　the　gate.　　©　2024　IEEE.