In this article, we present a high-performance SiGe junctionless FinFET (JLFinFET) on insulator by selective growth of buried oxide (SELBOX) layer device with better electrostatics. The mole fraction x = 0.1, 0.2, 0.3, 0.4, 0.5, and 0.7 with fin width 10 nm and gate length of 20 nm are considered for simulation using technology computer aided design (TCAD) Sentaurus device. With Si0.9Ge0.1 JLFinFET on insulator by SELBOX layer, nearly an ideal subthreshold swing of 61.51 mV/decade and enhanced on-current, off-current has been achieved. Evaluation of on-off current ratio, DIBL, SS for different parameters, such as doping concentration (1015-1019/cm3), channel length (10-40 nm), temperature (200-700°K) on JLJFinFET on insulator by SELBOX layer are presented. Three-dimensional device simulation using the TCAD software tool Sentaurus Device is used to simulate and the results are compared with a SELBOX JLFinFET. © 2020 Wiley Periodicals LLC.