This work presents a lateral RF BJT built on SOI-CMOS compatible substrate. The primary motivation is to realize a SOI-BiCMOS technology suitable for low power RF and mixed-signal SoC. This novel LBJT structure relies on a self-aligned polysilicon side-wall-spacer (PSWS) to connect the base contact to the intrinsic base with dimensions in 100 nm range. The fabricated LBJTs exhibit superior Johnson's product (fτ×BVCEO) in the range between 190-300 GHz·V. The fmax of the optimal device reaches 46 GHz at collector current density of only 0.15 mA/μm2. Both figure-of-merits are in-line with advanced SiGe-HBT devices, and superior than previously published data on lateral BJTs.