Low-frequency (LF) noise characteristics of wide planar junctionless transistors (JLTs) are investigated. Interestingly, carrier number fluctuation is the main contributor to the LF noise behavior of JLT devices, even though their bulk conduction features are clearly proved by the extracted flat-band voltage (V-fb). This is explained by the fact that mobile electrons in depletion, originating from the bulk neutral channel or source/drain regions, can interact with slow traps in the gate oxide, giving rise in return to fluctuations of the charge density in the bulk neutral channel. Similar values of trap density (N-t) are extracted in JLT devices and inversion-mode (IM) t0072ansistors, which also supports that the LF noise of JLT is well explained by the carrier number fluctuation model. (C) 2013 Elsevier Ltd. All rights reserved.