A　new　structure　IGBT　(insulated　gate　bipolar　transister)　is　proposed　for　reducing　the　power　dissipation.　It　features　a　composite　voltage-sustaining　layer　which　includes　a　n-type　buffer　layer　formed　by　ultra-deep　diffusion　and　a　transparent　backside　emitter　formed　by　boron　implantation.　Working　in　a　deep　punch-through　state　during　its　normal　operating　condition,　it　still　possesses　all　the　characteristics　of　the　robust　non-punch-through　IGBT　(NPT-IGBT).　With　a　chip-thickness　thinner　than　that　of　the　NPT-IGBT.　The　new　structure　presents　a　better　trade-off　relationship　between　the　on-state　voltage-drop　and　the　turn-off　loss.　The　experimental　results　show　that　the　power　loss　of　the　new　structure　IGBT　is　lower　than　that　of　the　NPT-IGBT　by　40%.