DEPENDENCE OF RF PERFORMANCE OF GaN/AlGaN HEMTS UPON AlGaN BARRIER LAYER VARIATION

2004 ◽  
Vol 14 (03) ◽  
pp. 750-755 ◽  
Author(s):  
ELIAS FARACLAS ◽  
RICHARD T. WEBSTER ◽  
GEORGE BRANDES ◽  
A. F. M. ANWAR
Keyword(s):  
Elevated Temperatures ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
Gate Bias ◽  
High Electron Mobility ◽  
Electron Mobility Transistors ◽  
Algan Barrier ◽  
Unity Gain ◽  
Algan Barrier Layer ◽  
Rf Performance

The dependence of microwave performance of GaN/AlGaN High Electron Mobility Transistors (HEMTs), namely the unity gain current cut-off frequency (fT) and the maximum oscillation frequency (fMAX), are reported as a function of the mole fraction of Al and the thickness of the barrier AlGaN layer. The parameters are computed using a physics-based model and compared to experimental results. Schrödinger and Poisson's equations are solved self-consistently to relate the applied gate bias to the channel electron concentration. The contributions of both spontaneous and piezoelectric polarizations towards f T are explored. Finally, because of interest in using this family of devices at elevated temperatures, each simulation was repeated between 300K and 500K for comparison.

AlGaN/GaN High Electron Mobility Transistors on Si/SiO2/poly-SiC Substrates

2006 ◽  
Vol 955 ◽  
Author(s):  
Travis Anderson ◽  
Fan Ren ◽  
Lars Voss ◽  
Mark Hlad ◽  
Brent P Gila ◽  
...  
Keyword(s):  
Electron Mobility ◽  
High Electron Mobility Transistors ◽  
Parameter Extraction ◽  
High Electron ◽  
High Electron Mobility ◽  
Drain Spacing ◽  
Electron Mobility Transistors ◽  
Algan Barrier ◽  
Rf Performance ◽  
Spacing Parameter

ABSTRACTThe dc and rf performance of AlGaN/GaN High Electron Mobility Transistors (HEMTs) grown by Molecular Beam Epitaxy on Si-on-poly (SopSiC) substrates is reported. The HEMT structure incorporated a 7 period GaN/AlN superlattice between the AlGaN barrier and GaN channel for improved carrier confinement. The knee voltage of devices with 2 μm gate-drain spacing was 2.12 V and increased to 3 V at 8 μm spacing. The maximum frequency of oscillation, fMAX, was ∼40 GHz for devices with 0.5 μm gate length and 2 μm gate-drain spacing. Parameter extraction from the measured rf characteristics showed a maximum intrinsic transconductance of 143 mS.mm−1.

scholarly journals Низкоэнергетическое бездефектное сухое травление барьерного слоя HEMT AlGaN/AlN/GaN

2018 ◽  
Vol 44 (10) ◽  
pp. 61
Author(s):  
С.В. Михайлович ◽  
А.Ю. Павлов ◽  
К.Н. Томош ◽  
Ю.В. Федоров
Keyword(s):  
Barrier Layer ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
High Electron Mobility ◽  
Inductively Coupled ◽  
Enhancement Mode ◽  
Electron Mobility Transistors ◽  
Algan Barrier ◽  
Algan Barrier Layer ◽  
First Time

AbstractA method of defectless dry etching of an AlGaN barrier layer is proposed, which consists in repeated plasmachemical oxidation of AlGaN and removal of the oxide layer by means of reactive ion etching in inductively coupled BCl_3 plasma. Using the proposed etching technology, AlGaN/AlN/GaN high-electron-mobility transistors (HEMTs) with a buried gate have been successfully fabricated for the first time. It is shown that the currents of obtained HEMTs are independent of the number of etching cycles, while the gate operating point shifts toward positive voltages up to obtaining transistors operating in the enhancement mode.

scholarly journals Gate-controlled amplifiable ultraviolet AlGaN/GaN high-electron-mobility phototransistor

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seung-Hye Baek ◽  
Gun-Woo Lee ◽  
Chu-Young Cho ◽  
Sung-Nam Lee
Keyword(s):  
Electron Mobility ◽  
Dark Current ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
Gate Bias ◽  
High Electron Mobility ◽  
Gan Hemt ◽  
Electron Mobility Transistors ◽  
Algan Barrier ◽  
Dimensional Electron Gas

AbstractGate-controlled amplifiable ultraviolet phototransistors have been demonstrated using AlGaN/GaN high-electron-mobility transistors (HEMTs) with very thin AlGaN barriers. In the AlGaN/GaN HEMTs, the dark current between the source and drain increases with increasing thickness of the AlGaN barrier from 10 to 30 nm owing to the increase in piezoelectric polarization-induced two-dimensional electron gas (2-DEG). However, the photocurrent of the AlGaN/GaN HEMT decreases with increasing thickness of the AlGaN barrier under ultraviolet exposure conditions. It can be observed that a thicker AlGaN barrier exhibits a much higher 2-DEG than the photogenerated carriers at the interface between AlGaN and GaN. In addition, regardless of the AlGaN barrier thickness, the source–drain dark current increases as the gate bias increases from − 1.0 to + 1.0 V. However, the photocurrent of the phototransistor with the 30 nm thick AlGaN barrier was not affected by the gate bias, whereas that of the phototransistor with 10 nm thick AlGaN barrier was amplified from reduction of the gate bias. From these results, we suggest that by controlling the gate bias, a thin AlGaN barrier can amplify/attenuate the photocurrent of the AlGaN/GaN HEMT-based phototransistor.

scholarly journals Performance Optimization of Nitrogen Dioxide Gas Sensor Based on Pd-AlGaN/GaN HEMTs by Gate Bias Modulation

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 400
Author(s):  
Van Cuong Nguyen ◽  
Kwangeun Kim ◽  
Hyungtak Kim
Keyword(s):  
Gas Sensors ◽  
Performance Optimization ◽  
Response Times ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
Gate Bias ◽  
High Electron Mobility ◽  
Electron Mobility Transistors ◽  
Gan Hemts ◽  
Sensing Characteristics

We investigated the sensing characteristics of NO2 gas sensors based on Pd-AlGaN/GaN high electron mobility transistors (HEMTs) at high temperatures. In this paper, we demonstrated the optimization of the sensing performance by the gate bias, which exhibited the advantage of the FET-type sensors compared to the diode-type ones. When the sensor was biased near the threshold voltage, the electron density in the channel showed a relatively larger change with a response to the gas exposure and demonstrated a significant improvement in the sensitivity. At 300 °C under 100 ppm concentration, the sensor’s sensitivities were 26.7% and 91.6%, while the response times were 32 and 9 s at VG = 0 V and VG = −1 V, respectively. The sensor demonstrated the stable repeatability regardless of the gate voltage at a high temperature.

Non-Recessed-Gate Enhancement-Mode AlGaN/GaN High Electron Mobility Transistors with High RF Performance

2004 ◽  
Vol 43 (4B) ◽  
pp. 2255-2258 ◽  
Author(s):  
Akira Endoh ◽  
Yoshimi Yamashita ◽  
Keiji Ikeda ◽  
Masataka Higashiwaki ◽  
Kohki Hikosaka ◽  
...  
Keyword(s):  
Electron Mobility ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
High Electron Mobility ◽  
Enhancement Mode ◽  
Electron Mobility Transistors ◽  
Rf Performance ◽  
Recessed Gate

A Study of Defects and Surface Properties in AlGaN/GaN High Electron Mobility Transistors (HEMTs) Grown by MOCVD on Semi-Insulating SiC Substrates

2006 ◽  
Vol 955 ◽  
Author(s):  
Yongkun Sin ◽  
Hyun I Kim ◽  
Paul Adams ◽  
Gary Stupian
Keyword(s):  
Surface Properties ◽  
Hall Mobility ◽  
Electron Mobility ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
Plan View ◽  
High Electron Mobility ◽  
Electron Mobility Transistors ◽  
Algan Barrier ◽  
Sheet Density

ABSTRACTAlGaN/GaN HEMTs (High Electron Mobility Transistors) grown on semi-insulating (SI) SiC substrates are very promising for high power, high speed, and high temperature operation with great potential for both military and commercial applications. These high performance characteristics are possible due to presence of high two-dimensional electron gas (2 DEG) charge sheet density maintaining a high Hall mobility at the AlGaN barrier/GaN buffer hetero-interface. However, reliability of AlGaN HEMTs still remains a major concern because of the large number of defects and traps present both in the bulk as well as at the surface leading to current collapse. We report on the study of defects and surface properties in MOCVD-grown Al0.27Ga0.73N HEMT structures on SI SiC substrates. Our HEMT structures consist of a 25nm thick undoped AlGaN barrier layer and a 3μm thick undoped GaN buffer layer grown on a 100nm thick AlN nucleation layer. Hall measurements showed a charge sheet density of ∼1013/cm2 and a Hall mobility of ∼1500cm2/V·sec. Both cross-sectional and plan view TEMs were employed to study defects in the heterostructures and XPS (X-ray Photoelectron Spectroscopy) and AES (Auger Electron Spectroscopy) employed to study surface properties in both GaN and AlGaN layers. DC characterization results from AlGaN Schottky diodes with Pt/Au Schottky contacts are also reported along with results from AlGaN/GaN HEMT devices.

Sign in / Sign up

Export Citation Format

Share Document