Subthreshold Characteristics of AlGaN/GaN MIS-FinFETs with Controlling Threshold Voltages

Abstract

AlGaN/GaN metal-insulator-semiconductor field-effect transistors with fin structures (AlGaN/GaN MIS-FinFETs) were fabricated and characterized by changing fin width and using different dielectric layers. The FinFET with 20 nm-thick SiO2 dielectric layer exhibits a very small subthreshold swing (SS) of 56 mV/decade. However, the threshold voltage of the device is too low to ensure low off-state leakage current (at the gate voltage of 0 V), even though the fin width of the device is reduced to 30 nm, which would not meet the requirement for low standby power consumption. On the other hand, the FinFET with a 10 nm-thick Al2O3 dielectric layer and a much wider fin width of 100 nm shows normally-off operation with a threshold voltage of 0.8 V, SS of 63 mV/dec, and very low off-state current of 1 nA/mm. When the fin width is reduced to 40 nm, the threshold voltage of the FinFET is increased to 2.3 V and the SS is decreased to 52 mV/decade. These excellent switching performances convince us that the FinFETs might be promising either for low voltage logic or for efficient power switching applications. The observed SS values, which are smaller than the theoretical Boltzmann limit (60 mV/decade), can be explained by the concept of the voltage-dependent effective channel width.

A Unified Depletion/Inversion Model for Heterojunction Trigate FinFETs DC Characteristics

“…Other device constants used for the simulation are reported in Table 2. Mobility, µ 0 , is evaluated using numerical optimization and the value so achieved is comparable to data reported previously [27]- [29].…”

Performance analysis of GaN‐FINFET for RFIC application with respect to different FinWidth's

“…Another crucial parameter to be considered is output conductance (g d ) which actually has an inverse relation with the gain of the device. It is said to be as the ratio of change in the current of the drain to the minute change in the voltage of the drain maintaining the voltage of the gate constant and defined mathematically in Equation (2).…”

“…As the bandgap of Gallium Nitride is almost three times of silicon, that is, 3.4 eV it is designated as Wide Band Gap material. The bandgap governs the electricfield in which the material could sustain, the wide bandgap property of the Gallium Nitride helps in order to enhance the semiconductors with narrow depletion regions, which automatically leads to the device structures having much more carrier density and could be packed densely 2 . The properties which Gallium Nitride acquire make it extremely suitable to fit into the field of power electronics.…”

“…The bandgap governs the electricfield in which the material could sustain, the wide bandgap property of the Gallium Nitride helps in order to enhance the semiconductors with narrow depletion regions, which automatically leads to the device structures having much more carrier density and could be packed densely. 2 The properties which Gallium Nitride acquire make it extremely suitable to fit into the field of power electronics. As it works with higher speed, greater efficiency, greater temperature resistance Gallium Nitride could sustain in the production of electronic devices that are faster, durable, more compact and efficient.…”