A　novel　GaAs-based　tunnel　field-effect　transistor　without　drain　junction　is　proposed　to　improve　the　on-state　current　and　its　performance　is　investigated.　The　transistor　uses　N-type　InGaAs　with　the　same　doping　concentration　in　the　channel　and　drain　to　form　junctionless　channel/drain　and　to　simplify　the　manufacture　process,　while　P-type　GaAsSb　is　used　in　the　source　to　produce　hetero　junction　source/channel　and　to　increase　the　on-state　current.　The　widened　tunnel　barrier　in　the　off-state　decreases　the　leakage　current,　and　the　promoted　band-to-band　tunneling　probability　in　the　on-state　increases　the　driving　current,　so　that　both　the　low　subthreshold　slope　and　the　high　ratio　between　on-state　current　and　off-state　current　are　obtained.　Numerical　simulations　show　that　the　novel　device　achieves　an　on-state　current　of　3.66×10-3A,　and　an　off-state　current　of　4.35×10-13A　under　0.4　V　voltage,　and　the　ratio　between　on-state　current　and　off-state　current　is　1010,　and　that　an　average　subthreshold　slope　of　27　mV/dec　and　a　DIBL　of　126　are　obtained.　©　2016,　Editorial　Office　of　Journal　of　Xi＇an　Jiaotong　University.　All　right　reserved.