Performance Enhancement of AlGaN/GaN HEMT by Optimization of Device Parameters Considering Nanometer Barrier Layer Thickness

2020 ◽  
Vol 19 (06) ◽  
pp. 2050011
Author(s):  
Yogesh Kumar Verma ◽  
Varun Mishra ◽  
Santosh Kumar Gupta
Keyword(s):  
Performance Enhancement ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
Barrier Layer Thickness ◽  
Gan Hemt ◽  
Transfer Characteristics ◽  
Strong Inversion ◽  
Present Design ◽  
Device Geometry ◽  
Dimensional Electron Gas

The two-dimensional electron gas (2DEG) at the heterointerface of AlGaN and GaN is a complicated transcendental function of gate voltage, so an analytical charge control model for AlGaN/GaN high electron mobility transistor (HEMT) is presented accounting for all the three regions of operation (i.e., sub-threshold, moderate, and strong-inversion region). In addition to it, the performance of AlGaN/GaN HEMT is highly dependent on the device geometry. Therefore, to get the optimum performance of the device it is advisable to optimize the parameters governing the device geometry. Accordingly, the output and transfer characteristics, threshold voltage, ON current, OFF current, and transconductance are calculated using numerical computations. The present design is tested to calculate the voltage transfer characteristics (VTC) and transient characteristics of the invertor circuit, after the optimization of the device parameters.

Effect of GaN Cap Layer on the Electrical Properties of AlGaN/GaN HEMT

2012 ◽  
Vol 217-219 ◽  
pp. 2393-2396 ◽  
Author(s):  
Han Guo ◽  
Wu Tang ◽  
Wei Zhou ◽  
Chi Ming Li
Keyword(s):  
Electrical Properties ◽  
Doping Concentration ◽  
Cutoff Frequency ◽  
High Electron Mobility Transistor ◽  
Current Gain ◽  
High Electron ◽  
Saturation Current ◽  
Gan Hemt ◽  
Cap Layer ◽  
Dimensional Electron Gas

The electrical properties of AlGaN/GaN heterojunction high electron mobility transistor (HEMT) are simulated by using sentaurus software. This paper compares two structures, the HEMT with GaN cap layer and the HEMT without GaN cap layer. The sentaurus software simulates the DC and AC characteristics of the two AlGaN/GaN HEMT structures. The HEMT with GaN cap layer can increase the maximum transconductance gm from 177ms/mm to 399ms/mm when the doping concentration of the cap layer is 3×1018cm-3 compared with the other structure under the same conditions. The simulation results indicate that the HEMT with cap layer can increase maximum transconductance gm, saturation current Ids, current-gain cutoff frequency fT, maximum oscillation frequency fmax and reduce the series resistance of the drain to source compared with the HEMT without GaN cap layer. The large Ids of the HEMT with cap layer is attributed to the increase of the concentration of two dimensional electron gas (2DEG). Moreover, the change of the doping concentration of the cap layer will affect the gm and Ids.

Ultrathin AlN/GaN Heterojunctions by MBE for THz Applications

2006 ◽  
Vol 955 ◽  
Author(s):  
Yu Cao ◽  
Debdeep Jena
Keyword(s):  
Electron Scattering ◽  
High Electron Mobility Transistor ◽  
Mean Free Path ◽  
Thz Radiation ◽  
High Electron ◽  
Gan Hemt ◽  
Qualified Candidate ◽  
Dimensional Electron Gas ◽  
Thz Applications ◽  
Strongly Damped

ABSTRACTHigh electron mobility transistor (NEMT) based on AlN/GaN can be the source to generate terahertz (THz) radiation. The basic requirements are that a) the electron density in the 2DEG should be large enough for ensuring that the electron-electron scattering mean-free path is much shorter than the distance between the contacts to ensure a viscous, fluid-like flow, and b) the mobility should be high enough such that the possible plasma modes are not strongly damped. To show AlN/GaN HEMT is a qualified candidate for THz generation, we have calculated the plasma frequency for the two-dimensional electron gas (2DEG) in the GaN channel and compared it with other material, such as Si, GaAs and InAs. 3nm AlN has been grown on the GaN substrate by Nitrogen-source radio-frequency molecular-beam expitaxy (RFMBE). The growth temperature has been optimized and found to be 730C. Results from Hall measurement show the electron charge is ∼2.5*1013 cm−2 with the mobility of 530 cm2/Vs (room temperature) and 860 cm2/Vs (77K). A series AlN samples have been grown and studied by AFM, which shows the critical thickness of AlN on GaN is between 4nm and 5nm.

scholarly journals The Influence of the Different Repair Methods on the Electrical Properties of the Normally off p-GaN HEMT

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 131
Author(s):  
Di Niu ◽  
Quan Wang ◽  
Wei Li ◽  
Changxi Chen ◽  
Jiankai Xu ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Electron Gas ◽  
High Electron Mobility Transistor ◽  
Repair Process ◽  
High Electron ◽  
Dimensional Electron ◽  
Two Dimensional Electron Gas ◽  
Gan Hemt ◽  
Gan Hemts ◽  
Dimensional Electron Gas

The influence of the repair process on the electrical properties of the normally off p-GaN high-electron-mobility transistor (HEMT) is studied in detail in this paper. We find that the etching process will cause the two-dimensional electron gas (2DEG) and the mobility of the p-GaN HEMT to decrease. However, the repair process will gradually recover the electrical properties. We study different repair methods and different repair conditions, propose the best repair conditions, and further fabricate the p-GaN HEMTs devices. The threshold voltage of the fabricated device is 1.6 V, the maximum gate voltage is 7 V, and the on-resistance is 23 Ω·mm. The device has a good performance, which proves that the repair conditions can be successfully applied to the fabricate of the p-GaN HEMT devices.

scholarly journals Physics-Based TCAD Simulation and Calibration of 600 V GaN/AlGaN/GaN Device Characteristics and Analysis of Interface Traps

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 751
Author(s):  
Yu-Lin Song ◽  
Manoj Kumar Reddy ◽  
Luh-Maan Chang ◽  
Gene Sheu
Keyword(s):  
Conduction Band ◽  
Computer Aided Design ◽  
Measurement Data ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
Device Structure ◽  
Gan Hemt ◽  
Fixed Charges ◽  
Vertical Electric Field ◽  
Aided Design

This study proposes an analysis of the physics-based TCAD (Technology Computer-Aided Design) simulation procedure for GaN/AlGaN/GaN HEMT (High Electron Mobility Transistor) device structures grown on Si (111) substrate which is calibrated against measurement data. The presence of traps and activation energies in the device structure will impact the performance of a device, the source of traps and position of traps in the device remains as a complex exercise until today. The key parameters for the precise tuning of threshold voltage (Vth) in GaN transistors are the control of the positive fixed charges −5 × 1012 cm−2, donor-like traps −3 × 1013 cm−2 at the nitride/GaN interfaces, the energy of the donor-like traps 1.42 eV below the conduction band and the acceptor traps activation energy in the AlGaN layer and buffer regions with 0.59 eV below the conduction band. Hence in this paper, the sensitivity of the trap mechanisms in GaN/AlGaN/GaN HEMT transistors, understanding the absolute vertical electric field distribution, electron density and the physical characteristics of the device has been investigated and the results are in good agreement with GaN experimental data.

scholarly journals A New Study on the Temperature and Bias Dependence of the Kink Effects in S22 and h21 for the GaN HEMT Technology

Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 353 ◽  
Author(s):  
Giovanni Crupi ◽  
Antonio Raffo ◽  
Valeria Vadalà ◽  
Giorgio Vannini ◽  
Alina Caddemi
Keyword(s):  
Short Circuit ◽  
Equivalent Circuit Model ◽  
Short Circuit Current ◽  
High Electron Mobility Transistor ◽  
Current Gain ◽  
Device Performance ◽  
High Electron ◽  
Gan Hemt ◽  
Temperature Conditions ◽  
Conventional Instrumentation

The aim of this feature article is to provide a deep insight into the origin of the kink effects affecting the output reflection coefficient (S22) and the short-circuit current-gain (h21) of solid-state electronic devices. To gain a clear and comprehensive understanding of how these anomalous phenomena impact device performance, the kink effects in S22 and h21 are thoroughly analyzed over a broad range of bias and temperature conditions. The analysis is accomplished using high-frequency scattering (S-) parameters measured on a gallium-nitride (GaN) high electron-mobility transistor (HEMT). The experiments show that the kink effects might become more or less severe depending on the bias and temperature conditions. By using a GaN HEMT equivalent-circuit model, the experimental results are analyzed and interpreted in terms of the circuit elements to investigate the origin of the kink effects and their dependence on the operating condition. This empirical analysis provides valuable information, simply achievable by conventional instrumentation, that can be used not only by GaN foundries to optimize the technology processes and, as a consequence, device performance, but also by designers that need to face out with the pronounced kink effects of this amazing technology.

scholarly journals Theoretical Study of InAlN/GaN High Electron Mobility Transistor (HEMT) with a Polarization-Graded AlGaN Back-Barrier Layer

Electronics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 885 ◽  
Author(s):  
Yan Gu ◽  
Dongmei Chang ◽  
Haiyan Sun ◽  
Jicong Zhao ◽  
Guofeng Yang ◽  
...  
Keyword(s):  
Electron Mobility ◽  
Theoretical Study ◽  
Lattice Relaxation ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
Two Dimensional ◽  
Drift Diffusion ◽  
High Electron Mobility ◽  
Al Content ◽  
Dimensional Electron Gas

An inserted novel polarization-graded AlGaN back barrier structure is designed to enhance performances of In0.17Al0.83N/GaN high electron mobility transistor (HEMT), which is investigated by the two-dimensional drift-diffusion simulations. The results indicate that carrier confinement of the graded AlGaN back-barrier HEMT is significantly improved due to the conduction band discontinuity of about 0.46 eV at interface of GaN/AlGaN heterojunction. Meanwhile, the two-dimensional electron gas (2DEG) concentration of parasitic electron channel can be reduced by a gradient Al composition that leads to the complete lattice relaxation without piezoelectric polarization, which is compared with the conventional Al0.1Ga0.9N back-barrier HEMT. Furthermore, compared to the conventional back-barrier HEMT with a fixed Al-content, a higher transconductance, a higher current and a better radio-frequency performance can be created by a graded AlGaN back barrier.

A differential extended gate-AlGaN/GaN HEMT sensor for real-time detection of ionic pollutants

2019 ◽  
Vol 11 (31) ◽  
pp. 3981-3986 ◽  
Author(s):  
Lei Zhao ◽  
Xinsheng Liu ◽  
Bin Miao ◽  
Zhiqi Gu ◽  
Jin Wang ◽  
...  
Keyword(s):  
Real Time ◽  
Electron Mobility ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
High Electron Mobility ◽  
Gan Hemt ◽  
Real Time Detection

In this study, we propose a differential extended gate (DEG)-AlGaN/GaN high electron mobility transistor (HEMT) sensor to detect ionic pollutants in solution.

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