This work investigates how temperature and channel geometry affect the analog performance of AlGaN/GaN high electron mobility transistors (HEMTs) fabricated on silicon. Devices with varying lengths and widths were characterized across a temperature range from -35 degrees C to 25 degrees C. Four different methods were used to extract the carrier mobility: effective mobility (mu eff) calculated from the ratio ID/(VG-VT) at low drain voltage; field-effect mobility (mu FE) obtained from the transconductance in the linear regime; low-field mobility (mu o) estimated from the drift-diffusion model; and peak transconductance mobility derived from the maximum value of gm. The results consistently followed the trend mu eff > mu FE > mu o, and all mobilities showed degradation with increasing temperature due to enhanced phonon scattering. Key parameters such as threshold voltage (VT), subthreshold swing (SS), transconductance (gm), DIBL, output conductance (gD), Early voltage (VEA), and intrinsic gain (AV) were also evaluated, confirming that temperature and geometry critically influence device performance.

In this article, a new methodology is proposed for MOSFET parameter extraction and modeling of transfer behavior from weak to strong inversion range in ohmic operation at cryogenic temperatures. The propounded methodology is based on an empirical mobility law which considers that the Coulomb scattering mechanism prevails in weak inversion, while it is the surface roughness mechanism in strong inversion at temperatures lower than 30K. It permits to extraction of the inversion charge from weak to strong inversion range through I - V measurements. It appears that the estimated inversion charge behavior may concur with the one analytically constructed using the Lambert-W function approach. The new methodology can be employed when the conventional mobility law, through a negative first-order intrinsic mobility attenuation factor, fails to model the Coulomb scattering mechanism in weak inversion at very cryogenic temperatures.

This work investigates the influence of gate metal selection on the gate leakage current of AlGaN/GaN high-electron-mobility transistors (HEMTs) through a systematic temperature-dependent analysis in the range of 238.5–473.15 K. A direct comparison between different gate-metal/process configurations characterized under the same measurement conditions is performed to clarify their impact on leakage mechanisms. The results reveal a transition between dominant conduction mechanisms as a function of temperature, electric field, and gate stack properties. At low temperatures and electric fields, the leakage current is mainly governed by tunneling-related processes, while thermally activated mechanisms become increasingly significant as temperature increases. Under high electric field conditions, the observed trend is consistent with Fowler–Nordheim tunneling. A semi-logarithmic analysis of ln (IG) as a function of inverse temperature shows the absence of a well-defined Arrhenius behavior, indicating that the leakage current is not dominated by a single thermally activated mechanism. Instead, the weak temperature dependence observed in several regimes suggests a strong contribution of tunneling-related transport, with additional mechanisms becoming relevant depending on the device structure and bias conditions. The results demonstrate that the transition between conduction mechanisms occurs over different temperature ranges depending on the gate metal, highlighting the critical role of the metal–semiconductor interface in defining leakage behavior. These findings provide improved insight into leakage mechanisms in GaN-based devices and offer guidance for device design and reliability optimization.

In this paper, the multiple channels of a MISHEMT device (Metal/Si3N4/AlGaN/AlN/GaN-Metal-Insulator-Semiconductor High Electron Mobility Transistor) are studied regarding their impact on fundamental DC and RF figures of merit. Although most authors treat the 2DEG channel as the MISHEMT main channel, it is shown that its MOS channel contribution to the different RF parameters is of great importance on some devices. This unique characteristic makes the MISHEMT RF parameters to be dependent on both VGS and VDS. The 2DEG channel presents a MAG value of 15 dB that is almost independent with the 2DEG channel length. In relation to a pure 2DEG conduction, the MOS channel is responsible for a large set of analog parameters improvements. It offers an increase of about 23 dB in maximum available gain (MAG), while sustaining a high fT and fmax for a larger range of VGS and drain current level.

In this article, the performance of vertical nanowire Gate All Around (GAA) junction-less pMOSFETs on SOI having an asymmetric architecture was investigated experimentally based on an in-depth study of their electrical characteristics. Current-voltage I-V characteristics in linear operation regime in forward and reverse operation modes are analyzed in a wide range of temperatures from 80 K up to 340 K. In addition to that Low Frequency Noise (LFN) was also studied as a function of the temperature. The main DC and LFN results are presented, showing unusual low field mobility degradation and LFN enhancement for lower temperatures. A correlation was found between the low field mobility degradation and the low frequency noise increasing at low temperature operation, suggesting a strong impact of coulomb scattering on both parameters at low temperatures.

This work presents an analysis on experimental analog behavior of MISHEMTs operating in the temperature range from 450 K down to 200 K. The drain current (IDS) presented a slight anomaly, especially for temperatures lower than 400 K. In the transconductance it is possible to visualize a second peak, suggesting a second conduction. As shown, the transconductance presented a low dependence on gate length, and an anomaly was observed for the devices at 350 K. The output conductance and transistor efficiency behavior suggest a competition between the effects of the MOS and HEMT conductions, present in the device. A new kink was observed in the output characteristic (IDSxVDS) at room temperature, which is caused by the HEMT and MOS conductions interaction, and it is even more noticeable for higher overdrive voltages (VGT). This effect is called MISHEMT kink effect (MH-kink) in this work. The MH-kink shifts toward higher V DS for higher overdrive voltage, showing the stronger influence of the MOS conduction on the total drain current. The unity gain frequency (ft) increases from 800 MHz (450 K) to 1.8 GHz (200 K), while the AV goes in opposite direction from 43 dB (450 K) to 38 dB (200 K). Considering that the intrinsic voltage gain is good enough even at low temperatures, the MISHEMT can be identified as a good candidate for analog applications.

A new Y-function methodology approach for the inversion charge over the gate capacitance ratio estimation from weak to strong inversion operation has been developed. Based on the drain current expression in the linear operation regime and classical mobility law, it is demonstrated that the inversion charge over the gate capacitance ratio may be estimated from weak to strong inversion operation without any approximation by solving a second-degree equation. This latter equation depends notably on the Y-function and on three parameters which are needed to be extracted, two in strong inversion (the gain factor GM and the second order mobility attenuation factor 02) and one in subthreshold zone (the subthreshold swing SS). This easy-to-use Y-function approach permits accurate and physical meaning electrical parameter extraction confirmed by the very good agreement between the experimental and the model of the drain current and of the transconductance behavior of advanced transistors from weak to strong inversion operation regime.

This research investigates the impact of source-drain series resistance (RSD) AlGaN/GaN high-electron-mobility transistors (HEMTs). Initially, the influence of RSD was analyzed in devices with varying geometries (Length and width; Lg and W) as well as in devices with identical dimensions but fabricated using different gate metal manufacturing techniques. Subsequently, the effect of RSD on key parameters, including carrier mobility (mu n), effective mobility (mu eff) and field effect mobility (mu FE), drain current (Id), output conductance (gd), trans-conductance (gm), threshold voltage (VT) and subthreshold slope (S) was assessed. The results reveal that RSD tends to decrease in transistors with lower Lg and higher W, highlighting a significant correlation with the channel's geometric structure. Additionally, transistors employing different gate metal splits exhibited variations in RSD. The results further revealed that a lower RSD enhances mu n, mu eff, mu FE, Id, gd, gm, and S, while reducing VT.

The performance of AlGaN/GaN High-Electron Mobility Transistors (HEMTs) fabricated on (111) silicon substrates has been experimentally investigated, aiming to verify the effect of different channel orientations on the main electrical parameters, such as drain current (ID), threshold voltage, transconductance (gm), and DrainInduced Barrier Lowering (DIBL). Moreover, the noise Power Spectral Density (PSD) with different channel orientations has also been characterized in linear operation. No noticeable differences on the electrical and noise PSD characteristics have been observed between the GaN channel orientations (0 degrees, 90 degrees and 45 degrees).

In this article, it is proven that in the framework of carrier number fluctuation mechanism, the input referred voltage noise is equal to the flat-band voltage noise only if the access resistances give a negligible contribution to the total device resistance. The expression of the correlated carrier number and mobility fluctuations (CNF/CMF) noise is revisited, and compact analytical equations are proposed. It is demonstrated that if the degradation of the intrinsic mobility in strong inversion is not too significant, considering a constant intrinsic Coulomb scattering coefficient or a constant intrinsic effective Coulomb scattering coefficient leads to similar extracted noise parameters. It is also proven that a constant extrinsic effective Coulomb scattering coefficient is physically incorrect if the access resistances impact cannot be neglected in the total device resistance.

This work presents the characterization of high mobility transistors (AlGaN/GaN HEMTs) produced with different techniques in the manufacturing process. The study performs a comparative analysis of the respective HEMTs. Here it is demonstrated that efficient HEMTs can be developed using 2 active implants without the need for specific heat treatment processes to create ohmic contacts or activate the device. The devices thus produced had higher drain current (I-d), output conductance (g(d)), transconductance (g(m)), field effect mobility (mu(eff)), effective mobility (mu(FE)) and low field mobility (mu(o)), in addition to lowest series resistance (R-SD), threshold voltage (V-T) and subthreshold slope (S). These results indicate that the adopted methodology not only simplifies the manufacturing process but also significantly improves the performance of HEMTs.

We present a critical assessment and discussion of the presence of parasitic source-and-drain series resistance and normal electric field-dependent mobility degradation in undoped Si nanosheet MOSFETs. A simple explicit Lambert W function-based closed-form model, continuously valid from sub-threshold to strong conduction, was used to clearly describe the transfer characteristics. The model was applied to experimental vertically stacked GAA undoped Si nanosheet MOSFETs using phenomenon-related model parameter values extracted from measured data through suitable numerical optimization procedures. The conducted analysis reveals and explains how these two effects produce analogous deleterious consequences on these devices’ transfer characteristics.

In this work, the low frequency noise (LFN) characteristics of Hydrogen-terminated diamond FETs are investigated. Both generation-recombination (GR) noise and flicker noise (1/f noise) are found to contribute to the LFN spectrum. The characteristic frequency of f(01) = 0.1 Hz, f(02) = 30 Hz, f(03) = 300 Hz and corresponding effective trap density (N-eff) of the GR centers are obtained. By changing the LFN measurement temperature, a trap activation energy level (E-a) of 0.12 eV is extracted from an Arrhenius plot. The dominant mechanism of the 1/f noise for the H-terminated diamond FETs follows the correlated mobility fluctuations (CMF) model. By fitting the experimental data to the CMF model, the trap density and scattering coefficient of the carriers are extracted to be 6.4x10(20) eV(-1) cm(-3) and 4x10(5) Vs/C. At last, the trap density of the H-terminated diamond FETs is compared with other state-of-the-art GaN and Si based devices. A moderate trap density was obtained without any interface optimization, suggesting that H-terminated diamond FETs could be a promising future technology for power electronics.

In this work, two types of gate-all-around (GAA) vertically stacked silicon nanosheet (NS) FETs are investigated, the main difference being the vertical distance between the stacked NSs. Principal electrical parameters are estimated at room and liquid nitrogen temperatures using a refined ${Y}$ -function methodology, the main advantage being that no extra iterative steps are necessary. The results are confirmed using other derivative dc parameter estimation methodologies. Low-frequency noise measurements evidence variability of the flat-band voltage noise and correlation between the noise level and the low field mobility. The dominant flicker noise mechanism is related to the correlated mobility and carrier number fluctuation mechanism with access resistance noise contribution in very strong inversion. The impact of the access resistance on the estimation of the Coulomb scattering coefficient is evidenced.

This work presents an experimental analysis of Metal-Insulator-Semiconductor High Electron Mobility transistor (MISHEMT) operating in a temperature range from 450 K down to 200 K, focusing on analog applications. The drain current and consequently the saturation transconductance (gmsat) showed to be slightly dependent on gate length. The output conductance (gD) presents a higher dependence with gate length than gmsat for the whole temperature range due to the influence of MOS conduction that is strongly affected by short channel effect. There is also a kink in the behavior of these parameters at 350 K, most likely due to the competition of temperature effects on different conduction mechanisms. The transistors showed a good performance in terms of analog application, where the intrinsic voltage gain (AV) increases from 38 dB (at 200 K) to 43 dB (at 450 K) for 800 nm gate length while the unity gain frequency (fT) decreases from 1.8 GHz (at 200 K) to 800 MHz (at 450 K) for a gate length of 400 nm, which makes MISHEMT a good candidate for analog applications.

In this work, the impact of the channel doping density on the low-frequency noise of silicon Gate-All-Around (GAA) Vertical Nanowire (VNW) pMOSFETs on Silicon-on-Insulator (SOI) substrates will be described and discussed. It is demonstrated that the dominant fluctuation mechanism of the 1/f noise in the subthreshold regime changes from number (& UDelta;n) to mobility (& UDelta;& mu;) fluctuations with increasing p-type doping density of the silicon nanowires. At the same time, the lowest input-referred voltage noise Power Spectral Density is observed for an intermediate boron concentration in the nanowire of 5 x 1018 cm-3.

In this work, the effect of the multiple conductions of a GaN based Metal-Insulator-Semiconductor High Electron Mobility Transistor (MIS-HEMT) when operating in a temperature range from 200K to 450K are evaluated experimentally. From 200K till 350 K the transfer curve of the 600nm gate length device shows the Zero Temperature Coefficient (ZTC) point clearly. However, for temperatures over 350 K, the threshold voltage (V TH ) shift towards higher gate voltage, which prevents the presence of ZTC bias point. This behavior is better explained through the transconductance (gm) curve where the HEMT and MOS conductions of the devices are being affected differently by temperature, resulting in a competition of effects that changes the behavior of the device in both, gm max and V TH as a function of temperature.

This paper compares the low-frequency noise performance of backside integrated pFinFETs versus their regular frontside-only processed counterparts. We report that no degradation of the dominant flicker noise is observed, comparing front- versus backside processed transistors. At the same time, application of a post backside processing annealing step(s) is shown to enable an improvement of the DC input characteristics and the low-frequency noise power spectral density of the devices.

In this paper the MISHEMT device (metal/Si 3 N 4 /AlGaN/AlN/GaN - metal–insulator–semiconductor high electron mobility transistor) is studied focusing mainly on the impact of the multiple conductions on the intrinsic voltage gain ( A v ). It is shown that the total drain current is composed of three different drain current components, whereof one is related to the MIS channel and the other two are related to high electron mobility transistor (HEMT) channels. The device output characteristics present double drain voltage saturation that gives rise to a double plateau in the saturation region of the output characteristics. This behavior relies also on the gate voltage, so the output characteristics and analog parameters extraction are bias dependent. The intrinsic voltage gain increases thanks to the early voltage increment in the second plateau where HEMT conduction is dominant. Electron concentration profiles were simulated in order to investigate the device saturation regime.