A　buried-oxide　trench-gate　bipolar-mode　JFET　(BTB-JFET)　with　an　oxide　layer　buried　under　the　gate　region　to　reduce　the　gate-drain　capacitance　Cgd　is　proposed.　Simulations　with　a　resistive　load　circuit　for　power　loss　comparison　at　high　frequency　application　are　performed　with　20V-rated　power　switching　devices,　including　a　BTB-JFET,　a　trench　MOS-FET　(T-MOSFET)　generally　applied　in　present　industry,　and　a　conventional　trench-gate　bipolar-mode　JFET　(TB-JFET)　without　buried　oxide,　for　the　first　time.　The　simulation　results　indicate　that　the　switching　power　loss　of　the　normally-on　BTB-JFET　is　improved　by　37%　and　14%　at　1MHz　compared　to　the　T-MOSFET　and　the　normally-on　TB-JFET,　respectively.　In　order　to　demonstrate　the　validity　of　the　simulation,　the　normally-on　TB-JFET　and　BTB-JFET　have　been　fabricated　successfully　for　the　first　time,　where　the　buried　oxide　structure　is　realized　by　thermal　oxidation.　The　experimental　results　show　that　the　Cgd　of　the　BTB-JFET　is　decreased　by　45%　from　that　of　the　TB-JFET　at　zero　source-drain　bias.　Compared　to　the　TB-JFET,　the　switching　time　and　switching　power　loss　of　the　BTB-JFET　decrease　approximately　by　7.4%　and　11%　at　1MHz,　respectively.　Therefore,　the　normally-on　BTB-JFET　could　be　pointing　to　a　new　direction　for　the　R　and　D　of　low　voltage　and　high　frequency　switching　devices.