Random telegraph signals and low-frequency noise in n-metal-oxide-semiconductor field-effect transistors with ultranarrow channels

The characteristics of low-frequency noise in n-metal-oxide-semiconductor field-effect transistors with ultranarrow channels have been investigated through random telegraph signals and low-frequency noise spectroscopy. Random telegraph signals with very large amplitude (∼70%) are observed in weak inversion at room temperature. Low-frequency noise spectra having both 1/fⁿ and Lorentzian type are found separately in the same channel at various gate bias voltages. The observations strongly suggest that the low-frequency noise is dominated by carrier mobility fluctuation in weak inversion and by carrier number fluctuation under high-field conditions in an ultranarrow channel.