To　improve　the　high　voltage　and　high　current　handling　capability,　a　model　of　strained　Si/SiGe　HBT　is　established　with　SILVACO　TCAD　to　study　the　influence　of　the　virtual　substrate　on　current　gain　of　the　device.　Higher　Ge　composition　of　the　base　can　be　achieved　with　the　virtual　substrate　while　keeping　the　strain　between　the　base　and　the　collector　constant,　and　hence　the　current　gain　is　enhanced.　However,　the　breakdown　voltage　is　too　low　to　increase　the　output　power　and　signal-to-noise　ratio　of　the　system.　A　new　design　of　selectively　implanted　collector　in　device　with　virtual　substrate　is　proposed　considering　that　collector　design　is　associated　with　the　breakdown　voltage　while　irrelevant　of　the　current　gain.　A　lateral　electric　field　is　built　up　with　the　design,　and　thereby　the　breakdown　voltage　is　enhanced.　Results　show　that　for　the　novel　device,　both　the　current　gain　and　the　breakdown　voltage　are　markedly　improved　and　the　figure　of　merit　β·VCEO　is　14.2　times　as　much　as　that　of　the　traditional　SiGe　HBT,　which　effectively　develops　the　high　voltage　and　high　current　application　of　microwave　power　SiGe　HBT.　©,　2015,　Beijing　University　of　Technology.　All　right　reserved.