Low-Frequency Noise Characteristics of GaN Nanowire Gate-All-Around Transistors With/Without 2-DEG Channel

Effect of Gate Structure on the Trapping Behavior of GaN Junctionless FinFETs

“…When matching S Id /I d 2 and (g m /I d ) 2 , the flatband voltage fluctuations (S Vfb ) are obtained to be 1 × 10 -8 V 2 •Hz -1 and 4.5 × 10 -9 V 2 •Hz -1 for the partially covered-and the overlapped-devices, respectively. Considering the actual gate length for the overlapped-device is L fin = 2 µm, the corresponding trap density (N t ) calculated using Equation (1) with λ = 0.11 nm is 2.1 × 10 20 cm -3 •eV -1 and 2.2 × 10 20 cm -3 •eV -1 [20], lower than the values reported from the GaN-based 3D devices [8]- [11]. This result suggests that the trap density of the GaN junctionless device is lower than the interface trap density in devices with surface channel.…”

“…Low frequency noise (LFN) measurements have great merits in analyzing the interface and/or oxide traps [7] and can also help identifying the conduction mechanism in semiconductor devices. There have been many studies dedicated to LFN for AlGaN/GaN MISHEMTs, AlGaN/GaN FinFETs, AlGaN/GaN omega FETs, AlInGaN/GaN Fin-HEMTs, and GAA FETs with/without AlGaN/GaN heterojunction [8]- [11]. It is generally admitted that the origin of the noise mechanism in most of GaN-based 3-dimensional (3D) devices is mainly due to the carrier number fluctuations (CNF) [7].…”

Graphene as a Schottky Barrier Contact to AlGaN/GaN Heterostructures

“…We are aware of only one study of noise in high-k Si MOSFET that reported a very small trap density of N t 10 17 eV −1 cm −3 [31]. Other studies of noise in AlGaN/GaN HEMTs with metal gate indicated N t = (10 18 -10 20 ) eV −1 cm −3 (see Figure 7b and References [23][24][25]32]). We also found a similar range of effective trap density N t = (2.3 × 10 19 -1.7 × 10 20 ) eV −1 cm −3 in AlGaN/GaN HEMT structures with Ni/Au gate.…”

“…Since in the linear regime n s ~ (V g − V t ), the McWhorter model predicts the dependence of noise on the gate voltage as . In many publications on noise in AlGaN/GaN transistors, deviations from this law have been reported (see, for example, References [ 24 , 25 ]). These deviations from the McWhorter model are usually attributed to the influence of the contact resistance, gate leakage current, mobility fluctuations, and dependence of the trap density N t on energy (gate voltage).…”

“…Figure 7 b compares the effective trap density as a function of the gate voltage swing extracted using Equation (4) for the same transistors as in Figure 7 a. The right panel indicates the ranges of the trap densities published for Si MOSFETs with high-k dielectric and for similar AlGaN/GaN transistors with the metal Schottky gate [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ].…”