Low-frequency noise investigation in long-channel fully depleted inversion mode n-type SOI nanowire

Abstract

This work presents a Low-Frequency Noise (LFN) investigation in fully depleted n-type Silicon-On-Insulator (SOI) nanowire transistors working in linear region with VDS = 50mV. Long-channel devices of 1μ {m and 10μ {m are evaluated. A wide range of fin width is considered in the LFN analysis, from 15nm up to 105nm. The results showed a flicker noise (1/FF) behavior and a decrease of normalized noise SID/IDs2 with gate voltage overdrive increase for frequencies bellow 500Hz. Above this frequency, it was possible to see that generation and recombination noise with 1/f2 decay overlaps the flicker noise, becoming the predominant noise source. The cut-off frequency increases with gate voltage overdrive while the gamma exponent decreases. Gamma reduces from 1.3 to 0.9 and from 0.95 to 0.65 for devices with channel length of 1 μ {m and 10μ {m, respectively. A major noise variation of about one order of magnitude with gate voltage overdrive increase was observed in devices of 1 μ {m long in comparison to channel length of 10μ {m. The devices showed weak noise dependence on fin width due to mobility decrease as nanowires become narrower.