Time　constant　spectra　are　extracted　from　current　transients　based　on　the　Bayesian　deconvolution　and　used　to　characterize　traps　in　GaN　high-electron　mobility　transistors.　Two　kinds　of　traps　with　different　time　constants　in　an　actual　device　were　identified　in　the　AIGaN　barrier　layer　and　the　GaN　layer,　respectively.　In　particular,　the　trapping　process　in　the　AIGaN　barrier　layer　was　identified　at　the　region　near　the　drain　side　under　gate　contact.　Trapping　mechanisms　of　both　two　traps　are　discussed.　Additionally,　we　observe　that　the　trap　in　the　AlGaN　barrier　layer　requires　sufficient　electric　field　to　activate　the　trapping　process　and　a　high　drain　voltage　(V-ds)　accelerates　the　trapping　processes　both　in　the　AIGaN　barrier　layer　and　the　GaN,layer.　In　addition,　detrapping　experiments　with　different　filling　conditions　were　performed　to　confirm　their　spatial　positions.　The　influence　of　self-heating　is　excluded　during　the　experiment　by　keeping　the　power　density　at　a　very　low　level,　and　the　trapping　effect　is　the　sole　factor　accounting　for　the　current　transients.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.