The　fast　recovery　diodes　(FRDs)　are　widely　used　in　high　frequency　and　high　power　applications.　The　forward　characteristics　of　the　FRDs,　such　as　the　forward　voltage　drop,　are　very　important　to　determine　the　property　of　the　FRDs.　The　forward　characteristics　of　the　FRD　always　greatly　depend　on　the　temperature.　Here,　in　this　paper,　we　researched　some　FRDs　with　special　structures　by　simulation　and　proposed　a　new　structure　to　farther　improve　the　temperature　coefficient　of　the　FRDs.　It　is　found　that,　a　diode　with　low　P+　emitter　efficiency,　and　a　P+　buried　layer　at　anode　junction　has　a　better　forward　temperature　coefficient.　It　proposes　a　guiding　way　to　design　the　FRDs　which　are　worked　in　the　positive　temperature　coefficient　(PTC)　area.　©2010　IEEE.