In this paper, for the first time, the nTFET reliability and stability have been studied against the adverse effect of positive bias temperature instability (PBTI) for three different device architectures, viz. elevated drain-(ED-), elevated source-(ES-) and elevated source–drain-(ESD-) TFETs, in terms of threshold voltage (VT) shift, on-current/off-current (ION/IOFF) deviation, off-current (IOFF) deviation and minimum subthreshold swing (SSmin) deviation for different PBTI stress conditions. The channel lengths for all the devices have been considered as 70 nm. It is found that the ES-TFET is showing maximum stability against the PBTI effect in terms of IOFF and ION with a VT shift of 2.9% and SSmin shift of 27%, while maintaining measurable absolute values of the aforementioned device parameters. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.