This paper explores source/drain (S/D) spacer technology-based reconfigurable field-effect transistors (RFETs) and a detailed physical insight toward the advantages of using spacer oxide in RFETs for applications involving rapid temperature fluctuations and reduction of circuit delay in contrast to conventional ambipolar FETs and other devices based on band-to-band tunneling (BTBT) such as TFETs. Temperature-based DC, analog and RF performance of gate-all-around (GAA), heterogeneous gate dielectric GAA, SiGe, and full silicon TFETs are compared. Moreover, it is also shown that the propagation delay in logic circuits is reduced for the proposed DG-RFET resulting in more robust and improved circuit performance.