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

NON-IDEAL CURRENT TRANSPORT IN HETEROSTRUCTURE FIELD EFFECT TRANSISTORS

2008 ◽  
Vol 18 (04) ◽  
pp. 935-947 ◽  
Author(s):  
ALEXEI KOUDYMOV ◽  
MICHAEL SHUR
Keyword(s):  
Field Effect ◽  
Field Effect Transistors ◽  
Electron Velocity ◽  
Output Current ◽  
Trapping Region ◽  
Current Voltage ◽  
Numerous Experimental Data ◽  
Heterostructure Field Effect Transistors ◽  
Output Conductance ◽  
Trapped Charge

We describe a new analytical model of a Heterostructure Field Effect Transistors (HFETs) that accounts for electron trapping in the gate-drain spacing of the device and for related non-ideal device behavior. Under conditions of a very strong trapping, the electron velocity saturates outside the gate, in the trapping region, and the negative trapped charge leads to relatively large differential output conductance at the drain voltages exceeding the knee voltage. Also under the conditions of severe trapping, the negative trapped charge leads to the positive offset of the output current-voltage (I-V) characteristic. The model describes quite well numerous experimental data for passivated and unpassivated AlGaN / GaN HFETs with and without field plates (FP) under different bias conditions.

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.

Microwave operation of GaN/AlGaN-doped channel heterostructure field effect transistors

1996 ◽  
Vol 17 (7) ◽  
pp. 325-327 ◽  
Author(s):  
M.A. Khan ◽  
Q. Chen ◽  
J.W. Yang ◽  
M.S. Shur ◽  
B.T. Dermott ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistors ◽  
Heterostructure Field Effect Transistors
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