We propose an analytical model for drain current and inversion charge in the subthreshold region for an underlap DG FinFET by using the minimum channel potential method,i.e.,the virtual source.The flicker and thermal noise spectral density models are also developed using these charge and current models expression.The model is validated with already published experimental results of flicker noise for DG FinFETs.For an ultrathin body,the degradation of effective mobility and variation of the scattering parameter are considered.The effect of device parameters like gate length L_g and underlap length L_(un) on both flicker and thermal noise spectral densities are also analyzed.Increasing L_g and L_(un),increases the effective gate length,which reduces drain current,resulting in decreased flicker and thermal noise density.A decrease of flicker noise is observed for an increase of frequency, which indicates that the device can be used for wide range of frequency applications. We propose an analytical model for drain current and inversion charge in the subthreshold region for an underlap DG FinFET by using the minimum channel potential method, ie, the virtual source. Flicker and thermal noise spectral density models are also developed using these charge and current models expression. The model is validated with already published experimental results of flicker noise for DG FinFETs. For an ultrathin body, the degradation of effective mobility and variation of the scattering parameters are gate. The effect of device parameters like gate length L_g and underlap length L un (un) on both flicker and thermal noise spectral densities are also analyzed.Increasing L_g and L_ (un), increasing the effective gate length, which reduces the drain current, resulting in decreased flicker and thermal noise density. A decrease of flicker noise is observed for an increase of frequency, which indicates that the device can be used for wide range of frequency applications.