Analog and mixed circuit analysis of nanosheet FET at elevated temperatures

Abstract

In this paper, for the first time, the performance of 3D Nanosheet FETs (NSFETs) is reported in the inversion (INV), accumulation (ACC), and junctionless (JL) modes at elevated temperatures. It is observed that, as the temperature increases from 25 °C to 200 °C, a decrement of 68% in mobility is observed for INV mode. In contrast, an increment of around 29% in mobility is observed for ACC and JL modes owing to the less scattering effects. Various crucial DC and analog/RF figures of merit (FOMs), such as SS, DIBL, gm, f T, etc, are assessed for different temperatures in all three modes. Further, the impact of temperature on circuit performance is demonstrated. From the circuit analyses, at 25 °C, an increment of around 12% in propagation delay is noticed for the JL and ACC mode inverter compared to the INV mode inverter due to higher I ON for INV mode. However, at 200 °C, JL inverter outperforms INV and ACC modes because of an increment in mobility. Moreover, for ring oscillator (RO), an oscillation frequency of 43.39 GHz, 38.9 GHz and 38.8 GHz for INV, ACC and JL mode ROs at 25 °C, whereas oscillation frequencies of 27.08 GHz, 39.2 GHz and 42.88 GHz are noticed for INV, ACC and JL mode ROs at 200 °C respectively. Though JL NSFET offers less intrinsic capacitances, at 25 °C, the frequency of oscillations (f osc) is high for INV mode because of higher I ON. Whereas, at 200 °C, the JL mode outperforms due to the absence of mobility degradation with temperature. These results will give an understanding of this future generation device at both device and circuit levels.