Investigation of Analog/RF and linearity performance with self-heating effect in nanosheet FET

Abstract

In vertically stacked gate-all-around Nanosheet FET (NSFET), the channels/sheets are wrapped by a low thermal conductivity material, which hinders the active heat flow path and, thus, raises reliability concerns. Therefore, the role of temperature, i.e., ambient condition and self-heating effect (SHE), become prime objectives that must be adequately addressed. In this work, through extensive TCAD simulations, we analyzed the DC/Analog/RF/Linearity characteristics of an NSFET, considering the cumulative effect of ambient temperature and SHE. Using well-calibrated TCAD models, we investigated: (i) the variation in device characteristics with and without considering SHE; (ii) the impact of SHE and ambient temperature on Analog/RF and Linearity characteristics using well-defined figure-of-merits (FoMs); (iii) the device optimization, i.e., the significance of the varying number of sheets (Nsheet) with considering SHE for optimal performance; (iv) the impact of varying temperature over the voltage gain of an NSFET-based common source (CS) amplifier considering SHE. The temperature variation (including SHE) significantly affects the ON current (e.g., reduced by 9.4%), resulting in the modulation in transconductance (gm). Therefore, the designed CS amplifier's gain is also altered by temperature variation (e.g., ranging from 250 K to 400 K). Hence, the proposed analysis is worth exploring to acquire the design guidelines for optimal and reliable DC/Analog/RF/Linearity characteristics of a Nanosheet transistor under various temperature conditions.