Advances in AlGaN/GaN/SiC Microwave Devices

2007 ◽  
Vol 556-557 ◽  
pp. 1017-1022 ◽  
Author(s):  
Michael J. Uren ◽  
Martin Kuball

Recent work on the thermal and electrical challenges in realizing AlGaN/GaN microwave heterojunction field effect transistors grown on SiC substrates is discussed. Raman thermography has been used to directly measure the self-heating induced lattice temperature rise with dramatically improved resolution and accuracy compared to traditional infrared techniques. It is demonstrated that defects in the SiC substrate can influence the temperature distribution within the active device with potential consequences for reliability. Microwave devices require an insulating GaN substrate material for device isolation. It is shown that the net deep level acceptor concentration has to be accurately controlled to suppress short-channel effects and to achieve radio frequency power efficient operation.

Author(s):  
Raj Kumar ◽  
Shashi Bala ◽  
Arvind Kumar

To have enhanced drive current and diminish short channel effects, planer MOS transistors have migrated from single-gate devices to three-dimensional multi-gate MOSFETs. The gate-all-around nanowire field-effect transistor (GAA NWFET) and nanotube or double gate-all-around field-effect transistors (DGGA-NTFET) have been proposed to deal with short channel effects and performance relates issues. Nanowire and nanotube-based field-effect transistors can be considered as leading candidates for nanoscale devices due to their superior electrostatic controllability, and ballistic transport properties. In this work, the performance of GAA NWFETs and DGAA-NT FETs will be analyzed and compared. III-V semiconductor materials as a channel will also be employed due to their high mobility over silicon. Performance analysis of junctionless nanowire and nanotube FETs will also be compared and presented.


2012 ◽  
Vol 67 (6-7) ◽  
pp. 317-326 ◽  
Author(s):  
Alireza Heidari ◽  
Niloofar Heidari ◽  
Foad Khademi Jahromi ◽  
Roozbeh Amiri ◽  
Mohammadali Ghorbani

In this paper, first, the impact of different gate arrangements on the short-channel effects of carbon nanotube field-effect transistors with doped source and drain with the self-consistent solution of the three-dimensional Poisson equation and the Schr¨odinger equation with open boundary conditions, within the non-equilibrium Green function, is investigated. The results indicate that the double-gate structure possesses a quasi-ideal subthreshold oscillation and an acceptable decrease in the drain induced barrier even for a relatively thick gate oxide (5 nm). Afterward, the electrical characteristics of the double-gate carbon nanotube field-effect transistors (DG-CNTFET) are investigated. The results demonstrate that an increase in diameter and density of the nanotubes in the DG-CNTFET increases the on-state current. Also, as the drain voltage increases, the off-state current of the DG-CNTFET decreases. In addition, regarding the negative gate voltages, for a high drain voltage, increasing in the drain current due to band-to-band tunnelling requires a larger negative gate voltage, and for a low drain voltage, resonant states appear


2005 ◽  
Author(s):  
Joshua N. Haddock ◽  
Xiaohong Zhang ◽  
Shijun Zheng ◽  
Seth R. Marder ◽  
Bernard Kippelen

2019 ◽  
Vol 14 (12) ◽  
pp. 1672-1679 ◽  
Author(s):  
Ningombam Ajit Kumar ◽  
Aheibam Dinamani Singh ◽  
Nameirakpam Basanta Singh

A 2D surface potential analytical model of a channel with graded channel triple material double gate (GCTMDG) Silicon-on-Nothing (SON) MOSFET is proposed by intermixing the benefits of triple material in gate engineering and graded doping in the channel. The surface potential distribution function of the GCTMDG SON MOSFET is obtained by solving the Poisson's equation, applying suitable boundary conditions, and using a parabolic approximation method. It is seen in the proposed device that the Short Channel Effects (SCEs) are subdued due to the apprehensible step in the surface potential profile that screen the potential of the drain. The effects of the various device parameters are studied to check the merit of the device. For the validation of the proposed device, it is compared with the simulated results of ATLASTM, a device simulator from SILVACO.


2009 ◽  
Vol 19 (01) ◽  
pp. 7-14 ◽  
Author(s):  
GRIGORY SIMIN ◽  
MICHAEL S. SHUR ◽  
REMIS GASKA

We present a novel approach to achieve terahertz-range cutoff frequencies and maximum frequencies of operation of GaN based heterostructure field-effect transistors (HFETs) at relatively high drain voltages. Strong short-channel effects limit the frequency of operation and output power in conventional geometry GaN HFETs. In this work, we propose a novel device with two additional independently biased electrodes controlling the electric field and space-charge close to the gate edges. As a result, the effective gate length extension due to short channel effects is diminished and electron velocity in the device channel is increased. Our simulations show that the proposed five-terminal HFET allows achieving fT=1.28 THz and fmax= 0.815 THz at the drain voltages as high as 12 V. Hence, this device opens up a new approach to designing THz transistor sources.


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