Anomalous random telegraph signal extractions from a very large number of n-metal oxide semiconductor field-effect transistors using test element groups with 0.47 Hz-3.0MHz sampling frequency

Random telegraph signal (RTS) noise in small gate area metal oxide semiconductor (MOS) transistors occurs frequently and causes serious problems in the field of flash memories and complementary MOS (CMOS) image sensors. The trap in the gate insulator, which is considered the origin of RTS, varies widely in terms of spatial location and energy level, so that RTS characteristics including the amplitude and time constants have large variability by nature and statistical analysis of RTS should become indispensable. In this paper, we propose a high-speed RTS measurement system with a newly developed test circuit and discuss the drain current and temperature dependences of RTS amplitude distributions. Moreover, we expand the sampling frequency between 0.47 Hz-3.0MHz and the observation length up to about 4 h and can thereby observe some anomalous RTSs such as ones with long time constants, ones generated abruptly, and ones disappearing.