Current-Voltage Characteristics of Ungated AlGaN/GaN Heterostructures

1999 ◽  
Vol 572 ◽  
Author(s):  
J. D. Albrecht ◽  
P. P. Rudento ◽  
S. C. Binari ◽  
K. Ikossi-Anastasiou ◽  
M. G. Ancona ◽  
...  
Keyword(s):  
Electron Transport ◽  
Heat Dissipation ◽  
Field Effect Transistors ◽  
Electron Velocity ◽  
Saturation Field ◽  
Velocity Saturation ◽  
Process Characterization ◽  
Current Saturation ◽  
Heterostructure Field Effect Transistors ◽  
Gan Heterostructure

ABSTRACTResults of a systematic study of the current vs. voltage characteristics of ungated AIGaN/GaN heterostructures grown on sapphire substrates are presented. It is experimentally observed that the saturation current nearly doubles as the source-to-drain channel lengths decrease from 11.8 to 1.7μm. The average electric field at which current saturation occurs is 10 to 30kV/cm, i.e. much less than the electron velocity saturation field. The experimental data is interpreted in the framework of a new model that takes into account the non-uniformity of the electron density in the channel, electron velocity saturation, and thermal effects. The temperature dependent electron transport characteristics of the model are based on Monte Carlo simulations of electron transport in GaN. It is shown that appreciable contact resistance, which leads to partial channel depletion near the source, and significant self-heating of the devices under high drain-to-source bias are the main reasons for the observed current saturation. The effective ambient temperature in the channel of the devices is calculated from a two-dimensional thermal model of heat dissipation through the sapphire substrate. Equilibrium channel carrier concentrations and low-field mobilities are determined from Hall effect data. The ungated structures are demonstrated to provide much useful materials and process characterization data for the development of AIGaN/GaN heterostructure field effect transistors.

Electron velocity saturation in heterostructure field-effect transistors

1990 ◽  
Vol 37 (3) ◽  
pp. 530-535 ◽  
Author(s):  
C.-J. Han ◽  
P.P. Ruden ◽  
T.E. Nohava ◽  
D.H. Narum ◽  
D.E. Grider ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistors ◽  
Electron Velocity ◽  
Velocity Saturation ◽  
Heterostructure Field Effect Transistors

Self-Heating Effects in High-Power AlGaN/GaN HFETs

2001 ◽  
Vol 693 ◽  
Author(s):  
M. Kuball ◽  
M.J. Uren ◽  
J.M. Hayes ◽  
T. Martin ◽  
J.C.H. Birbeck ◽  
...  
Keyword(s):  
Heat Dissipation ◽  
Field Effect Transistors ◽  
Three Dimensional ◽  
Non Invasive ◽  
Self Heating ◽  
Heating Effects ◽  
Heterostructure Field Effect Transistors ◽  
Gan Heterostructure ◽  
Temperature Maps ◽  
Better Than

AbstractWe report on the non-invasive measurement of temperature, i.e., self-heating effects, in active AlGaN/GaN heterostructure field effect transistors (HFETs). Micro-Raman spectroscopy was used to produce temperature maps with ≈1 μm spatial resolution and a temperature accuracy of better than 10°C. Significant self-heating effects in the source-drain opening of AlGaN/GaN HFETs were measured. Devices grown on sapphire and SiC substrates were compared. Three-dimensional finite-difference heat dissipation calculations were performed as function of device geometry.

Analysis of Thermal Characteristics of AlGaN/GaN Heterostructure Field-Effect Transistors Using Micro-Raman Spectroscopy

2021 ◽  
Vol 21 (11) ◽  
pp. 5736-5741
Author(s):  
Jengsu Yoo ◽  
Soo-Kyung Chang ◽  
Gunwoo Jung ◽  
Kyuheon Kim ◽  
Tae-Soo Kim ◽  
...  
Keyword(s):  
Field Effect ◽  
Heat Dissipation ◽  
Field Effect Transistors ◽  
Thermal Characteristics ◽  
Electrode Structure ◽  
Self Heating ◽  
Gate Structure ◽  
Heating Effects ◽  
Heterostructure Field Effect Transistors ◽  
Gan Heterostructure

We investigated the heat dissipation in heterostructure field-effect transistors (HFETs) using microRaman measurement of the temperature in active AIGaN/GaN. By varying the gate structure, the heat dissipation through the gate was clearly revealed. The temperature increased to 120 °C at the flat gate device although the inserted gate increased to only 37 °C. Our results showed that the inserted gate structure reduced the self-heating effect by three times compared to the flat gate structure. Temperature mapping using micro-Raman measurement confirmed that the temperature of the near gate area was lower than that of the near drain area. This indicated that the inserted gate electrode structure effectively prohibited self-heating effects.

Electron Transport Mechanism for Ohmic Contact to GaN/AlGaN/GaN Heterostructure Field-Effect Transistors

2013 ◽  
Vol 60 (9) ◽  
pp. 2788-2794 ◽  
Author(s):  
Yuji Ando ◽  
Kohji Ishikura ◽  
Yasuhiro Murase ◽  
Kazunori Asano ◽  
Isao Takenaka ◽  
...  
Keyword(s):  
Electron Transport ◽  
Ohmic Contact ◽  
Field Effect ◽  
Transport Mechanism ◽  
Field Effect Transistors ◽  
Heterostructure Field Effect Transistors ◽  
Gan Heterostructure

High-Temperature Electron Transport Properties in AlGaN/GaN Heterostructure Field Effect Transistors

2000 ◽  
Vol 639 ◽  
Author(s):  
Narihiko Maeda ◽  
Tadashi Saitoh ◽  
Kotaro Tsubaki ◽  
Toshio Nishida ◽  
Naoki Kobayashi
Keyword(s):  
High Temperature ◽  
Electron Transport ◽  
Temperature Dependence ◽  
Transport Properties ◽  
Field Effect ◽  
Room Temperature ◽  
Field Effect Transistors ◽  
Heterostructure Field Effect Transistors ◽  
Electron Transport Properties ◽  
Gan Heterostructure

Electron transport properties in the Al0.15Ga0.85N/GaN heterostructure field effect transistors (HFETs) have been examined from room temperature up to 400°C. The temperature dependencies of the two-dimensional electron gas (2DEG) mobility have been systematically measured for the samples with different 2DEG densities. The 2DEG mobility has decreased with increasing the temperature, however, its decrease ratio has been no longer large above 300°C. Moreover, the 2DEG mobility has found to be less dependent on the 2DEG density at higher temperatures. These observed features indicate that the 2DEG mobility above room temperature is limited by longitudinal optical (LO) phonon scattering, as is expected by theoretical prediction. The observed 2DEG mobilities at 400°C were as high as from 100 to 120 cm2/Vs, directly providing the evidence for suitability of the HFET of this material system for high-temperature applications. The temperature dependence of the transconductance (gm) of a HFET device has also been examined up to 400°C. It has been revealed that the temperature dependence of gm has basically the same features as those of the 2DEG mobility in the corresponding temperature region.

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