Drain currents and their excess noise in triple gate bulk p-channel FinFETs of different geometry

摘要

The drain current I, spectral density of the low-frequency 1/f noise S_t and transconductance g_m of triple gate bulk p-channel field-effect transistors (FinFETs) fabricated on 200 mm diameter Cz silicon wafers have been studied in the standard (ST) and Dynamic Threshold Voltage (DT) modes of operation. For the ST regime, a sub-linear increase of the drain current /with increasing overdrive voltage | V_ov| and practically no changes in the spectral density S_t of the noise are observed at high values of |V_ov|. The effect is attributed to a sub-linear increase of the free hole density in the channel, whereby the mobility does not change with increasing |V_ov|. An increase of the values of I, S_I and g_m normalized for the device geometry with increasing L_eff found and is attributed to the decrease of the mobility degradation coefficient with increasing L_eff. For the DT regime of operation, the decrease of the threshold voltage |V_th| is not accompanied by an increase of the drain current which decreases with increasing |V_Gf| due to the high leakage current passing through the forward biased drain and source junctions. However, that decrease of the drain current is not accompanied by changes in the value of S_I.