1/f noise in the linear region of LDD MOSFETs

A lightly doped drain (LDD) MOSFET can be decomposed as an intrinsic MOSFET in series with n/sup -/ source and drain regions. Under the assumption that the 1/f noise mainly comes from the intrinsic MOSFET part of the device, an expression for the drain noise power spectrum was developed in terms of terminal voltages. Noise measurements were performed on n-channel devices with effective channel lengths varying from 0.87 to 11.37 mu m. Good agreement between experimental values and theoretical values for a device channel length shorter than 4 mu m was obtained. It was also found that the LDD device has less noise than a conventional-structured MOSFET with the same channel length and operated under same terminal voltages.<>