Anomalous Capacitance Induced by GIDL in P-Channel LTPS TFTs

Abstract

In this letter, a mechanism of anomalous capacitance in p-channel low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) was investigated. In general, the effective capacitance was only the overlap region and independent with the frequency in LTPS TFTs under the off state. However, our experimental results reveal that the capacitance was related with the leakage current and that it was dependent with the measurement frequencies when operated at the off-state region. The increase of the capacitance value is verified to be due to the increase of the electron capacitance originating from a gate-induced drain-leakage (GIDL) one. Nevertheless, the GIDL-induced electron capacitance can be suppressed by employing band-to-band hot electron stress.