Electric field control of charge carrier density through dielectric layers has long been a key technology in the semiconductor industry and condensed-matter physics. The new carrier-doping method by the electric double layers (EDLs) opens up the route to access clean carrier doping with high carrier density, but this method is not practical for a switching device due to its slow response to the electric field. However, if this slow response could be stopped at room temperature as an extreme case, the EDL method can become the practical means for materials design, which produces a persistent carrier-doped state without impurity introduction or continuous supply of external electric fields. Here, it is demonstrated that the thermally programmable persistent interfacial metallic state can be realized around room temperature by all-solid heterointerface devices using an inorganic-glass solid electrolyte as a gate insulator. The proposed device, in this study, could pave the way for designing a new category of a highly carrier-doped semiconductor.