Reduction Of Peak Electric Field Research Articles

Revolutionizing Fe doped back barrier AlGaN/GaN HEMTs: Unveiling the remarkable 1700V breakdown voltage milestone

This research investigates the enhanced device breakdown capabilities of silicon-based AlGaN/GaN High Electron Mobility Transistors (HEMT). By incorporating various back barrier materials, a significant improvement in peak electric field and breakdown voltage is observed. Specifically, the integration of iron (Fe) doping into the Gallium Nitride (GaN) back barrier layer, combined with different back barrier materials such as Aluminum Gallium Nitride (AlGaN) and Indium Gallium Nitride (InGaN), results in an impressive increase of up to 1700 V. This improvement is attributed to the reduction of peak electric field at the gate edge. The optimized layer configurations significantly contribute to the overall performance of silicon substrate GaN HEMT devices, making them promising candidates for high-voltage applications in electric vehicles and high-power applications.

Reduced OFF-state current and suppressed ambipolarity in a dopingless vertical TFET with dual-drain for high-frequency circuit applications

In this article, a dopingless TFET with dual-drain and reversed T-shaped channel (DLVIT-TFET) is investigated to offer improvement in ON-state current (IOn) along with the reduction in OFF-state leakage current (IOff) and in ambipolarity. The investigated device has a dual channel region which helps in improving the on-state parameters like IOn and subthreshold swing (SS) due to the extended tunneling area. The inverted T-shaped channel minimizes the charge carriers to tunnel during the off-state, thereby reducing the magnitude of IOff. The results obtained from 2D TCAD simulation show that the investigated device provides ∼1 order of improvement in IOn and ∼3 orders of improvement in IOff. Furthermore, DLVIT-TFET offers an ∼3 orders of improvement in ambipolar current (IAmb) due to a reduction in peak electric field at channel-drain interface caused by splitting of drain potential at ambipolar state. Moreover, various analog/RF parameters such as transconductance (gm), gate parasitic capacitance (Cgd, and Cgs), cut-off frequency (fTmax), gain-bandwidth product (GBP), transconductance-frequency product (TFP) and transit time (τ) are found to be improved in DLVIT-TFET compared to the conventional DL-TFET. In addition, the transient analysis of DLVIT-TFET based inverter is analyzed, which shows improvement in the parameters like propagation delay and voltage swing. Finally, reliability of the investigated device is discussed by considering the effect of interface trap charges (ITCs) and variation in ambient temperature and it is observed that DLVIT-TFET is more immune to such defects and environmental factors than the conventional one.

Novel super junction technique used in AlGaN/GaN HEMT for high power applications

In this paper, a novel super junction technique in AlGaN/GaN HEMT is proposed and analyzed. The novel super junction is capable of splitting the potential drops to two points rather than a single point in the lateral axis (channel axis). Technology Computer Aided Design (TCAD) physical simulator is used to investigate the proposed GaN HEMT. Analyses of the simulation results, shows that the breakdown voltage of proposed AlGaN/GaN HEMT with super junction is higher than that of a conventional device. Proposed device demonstrated a breakdown voltage improvement of 26%. This is due to the reduction of peak electric field using super junction and it is evidenced in the simulation. Further, the Johnson figure of merit (JFOM) is extracted. The JFOM of proposed and conventional AlGaN/GaN HEMT are 4.89 × 1012 V s−1 and 3.79 × 1012 V s−1, respectively. The JFOM in the proposed device is improved by 23%. This improvement is mainly due to the improvement of breakdown voltage rather than cut-off frequency. Overall, the proposed device is a promising candidate for high-power applications as it can withstand higher voltages without compromising the switching-frequency.

Back-gate bias effect on the linearity of pocket doped FDSOI MOSFET

In this article, we investigate the feasibility of enhancing the linearity Figures of Merit (FoMs) by introducing pocket implant in the source/drain regions of the FDSOI MOSFET with ground plane (GP) under the influence of back-gate bias (VB) effect. The current investigations are carried out using a well calibrated industry standard simulation tool Silvaco ATLAS. The proposed device architecture shows reduction in peak electric field, improvement in effective mobility (μeff), subthreshold slope (SS), threshold voltage (VTH) & off-state current (IOFF) by rearranging the accumulated charges that can mitigate impact ionization. The improvement in these parameters leads to enhanced the fundamental transconductance term (gm) and in turn boosts the linearity, which can make it essential for RF/wireless IC designs. An investigation is performed to figure out the non-linear behaviour of proposed FDSOI MOSFET with pockets design by simulating the DC characteristics. The vital FoMs such as higher order transconductance coefficients, intermodulation distortion (IM) and input intercept point (IIP) are explicitly analysed along with the impact of VB.

Reliability of H-terminated diamond MESFETs in high power dissipation operating condition

The aim of this work is to study the catastrophic and gradual degradation of H-terminated diamond MESFETs. Such devices are able to withstand high power densities before failure, but are still affected by a bias-dependent degradation. The main degradation modes are both an increase in ON-resistance and threshold voltage. The effect of this device degradation seems to be caused by the higher concentration of a 0.3 eV deep level. Moreover, the presence of a possible variation in hole transfer efficiency cannot be excluded, especially at the highest stress biases. Electroluminescence measurements confirm the increase in hole scattering, and highlight a progressive reduction in peak electric field in the device under test, possibly due to a virtual field plate effect.

Surface Al doping of 4H-SiC via low temperature annealing

We present a method of forming shallow p-doping on a 4H-SiC surface by depositing a thin Al layer (d = 5 nm) and then thermally annealing it at 1000 °C for 10 min. A secondary ion mass spectrometry analysis of the annealed Al/SiC sample reveals an Al concentration in excess of 1017 cm−3 up to a depth of d ≤ 250 nm. I–V measurements and CV characterizations of Ti-SiC Schottky barrier diodes (SBDs) fabricated on a n-type SiC epi-wafer indicate that the shallow Al doping increases the built-in potential of the junction and the barrier height by ΔVbi=0.51 eV and ΔϕB=0.26 eV, respectively. Assuming a rectangular doping profile, calculations of the built-in voltage shift and the Schottky barrier height indicate that partial dopant activation (activation ratio ∼2%) can induce the observed barrier height shift. The shallow doping method was then used to fabricate junction terminations in SBDs which increased the breakdown voltage and reduced the reverse leakage current. Technology CAD simulations of the SBD with and without doping verify that a reduction of peak electric field can explain the improvement of the breakdown voltage.

A novel trench gate floating islands power MOSFET (TG-FLIMOSFET): Two-dimensional simulation study

Novel trench gate floating islands MOSFET (TG-FLIMOSFET) designed using the concept of “Opposite Doped Buried Regions” (ODBR) and floating islands (FLI) along with trench gate technology is proposed and verified using two-dimensional simulations. The conventional FLIMOSFET experimentally demonstrated recently, although offers lowest on-resistance in the low voltage range, however, suffers from quasi-saturation effect like any other power MOSFETs. The proposed TG-FLIMOSFET demonstrated to obtain about 30% reduction in peak electric field in drift region of the proposed device. TG-FLIMOSFET also demonstrates quasi-saturation free forward and transconductance characteristics, improved synchronous rectifying characteristics, identical breakdown voltage, reduced on-resistance and increased transconductance ‘gm’ when compared with the conventional FLIMOSFET for various trench geometries. The proposed device breaks the limit set by the conventional FLIMOSFET approximately by a factor of 10. A possible process flow sequence to fabricate the proposed device commercially by integrating multi-epitaxial process with trench gate technology is also presented.

Design of AlGaN/GaN HEMTs employing mesa field plate for breakdown voltage enhancement

We proposed the AlGaN/GaN high electron mobility transistors (HEMTs) employing the mesa field plate and carried out the detailed numerical simulation of device operation using ISE-TCAD. The reduction of peak electric field is required to achieve the high breakdown voltage of AlGaN/GaN HEMTs. Proposed AlGaN/GaN HEMT with both gate and mesa field plates simultaneously reduced the electric field concentration at the gate and the drain edge by decreasing the potential gradient along the 2-DEG channel. As the peak electric field at the drain edge was decreased, the breakdown voltage was increased by 66% compared with the AlGaN/GaN HEMT with the gate field plate only. The breakdown voltage could be increased without sacrificing any other forward characteristics due to the SiO2 passivation layer.

High breakdown voltage AlGaN/GaN HEMTs employing fluoride plasma treatment

We proposed channel-modulated AlGaN/GaN high electron mobility transistors (HEMTs) employing fluoride plasma treatment and carried out a detailed numerical simulation of device operation using ISE TCAD software. A reduction of peak electric field is required for achieving the high breakdown voltage of AlGaN/GaN HEMTs. The proposed channel-modulated AlGaN/GaN HEMTs created the fluoride plasma-treated region between the gate and the drain. The fluoride plasma-treated region modulated the two-dimensional electron gas (2-DEG) channel concentration, and effectively reduced the peak electric field without any field plates. The reduction of peak electric field in the gate-to-drain region caused the breakdown voltage to increase by 206%. The dc characteristics of channel-modulated AlGaN/GaN HEMTs remained practically the same as those of the conventional AlGaN/GaN HEMTs. The breakdown voltage could be increased without a significant degradation of dc characteristics due to the SiO2 passivation layer. The deposition of the SiO2 passivation layer combined with fluoride plasma treatment is a powerful process for channel-modulated AlGaN/GaN HEMTs.

Dynamic avalanche in diodes with local lifetime control by means of palladium

The increase of the static breakdown voltage and the reduction of dynamic avalanche in a fast recovery 2.5 kV/150 A P-i-N diode subjected to the radiation enhanced diffusion of a palladium are discussed. The in-diffusing palladium compensates the doping profile in a lightly doped N-base close to the anode junction. Using a device simulation, the increase of the breakdown voltage and the reduction of the dynamic avalanche are explained by the reduction of peak electric field in the additional low-doped P-type layer created by the compensation effect. This is presented for both a dc and transient device operation and confirmed experimentally as well. An improved technology curve for the static versus recovery losses at a high line voltage has been obtained. A high thermal budget of deep levels and a low leakage current are additional benefits of the method.