Self-aligned metal double-gate junctionless p-channel low-temperature polycrystalline-germanium thin-film transistor with thin germanium film on glass substrate

Abstract

Low-temperature (LT) polycrystalline-germanium (poly-Ge) thin-film transistors (TFTs) are viable contenders for use in the backplanes of flat-panel displays and in systems-on-glass because of their superior electrical properties compared with silicon and oxide semiconductors. However, LT poly-Ge shows strong p-type characteristics. Therefore, it is not easy to reduce the leakage current using a single-gate structure such as a top-gate or bottom-gate structure. In this study, self-aligned planar metal double-gate p-channel junctionless LT poly-Ge TFTs are fabricated on a glass substrate using a 15-nm-thick solid-phase crystallized poly-Ge film and aluminum-induced lateral metallization source–drain regions (Al-LM-SD). A nominal field-effect mobility of 19 cm2 V−1 s−1 and an on/off ratio of 2 × 103 were obtained by optimizing the Al-LM-SD on a glass substrate through a simple, inexpensive LT process.