This work investigates the performance of the inverted-T (IT) junctionless (JL) FinFET with selective buried oxide (SELBOX) topology. The electrical characteristics of SELBOX-ITJL FinFET are analyzed and compared with the ITJLFinFET. The performance of the SELBOX-ITJL FinFET is estimated for different SELBOX lengths (LSELBOX), substrate doping, UTB thickness (tsi). SELBOX-ITJL FinFET exhibits better ION, ION/IOFF, SS and DIBL for LSELBOX ≈ gate length (Lg). Unlike ITJL FinFET, substrate doping empowers to engineer the threshold voltage (VTH) of the proposed device. ION of the SELBOX-ITJLFET is improved by 48% and 9% compared to JLFET and ITJLFET respectively. Performance of SELBOX-ITJL FinFET at high temperatures (up to 550 K) is illustrated. The self-heating effect in SELBOX device is also studied and it is observed that the proposed device exhibits better immune to self-heating as compared to ITJL FinFET. Virtual device modeling and extensive device simulations are carried out using Synopsys Sentaurus TCAD tools (sprocess & sdevice). © 2019, Springer Nature B.V.