scholarly journals Gallium nitride heterostructure field-effect transistor with a heat-removal system based on a trench in the passivation layer filled by a high thermal conductivity material

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 74-82
Author(s):  
V. S. Volcheck ◽  
V. R. Stempitsky
Keyword(s):  
Thermal Conductivity ◽  
Gallium Nitride ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Heat Removal ◽  
High Thermal Conductivity ◽  
Device Structures ◽  
Effect Transistor ◽  
Heat Removal System ◽  
Removal System

The self-heating effect poses a main problem for high-power electronic and optoelectronic devices based on gallium nitride. A non-uniform distribution of the dissipated power and a rise of the average temperature inside the gallium nitride heterostructure field-effect transistor lead to the formation of a hot spot near the conducting channel and result in the degradation of the drain current, output power and device reliability. The purpose of this work is to develop the design of a gallium nitride heterostructure field-effect transistor with an effective heat-removal system and to study using numerical simulation the thermal phenomena specific to this device. The objects of the research are the device structures formed on sapphire, each of whom features both a graphene heat-eliminating element on its top surface and a trench in the passivation layer filled by a high thermal conductivity material. The subject of the research is the electrical and thermal characteristics of these device structures. The simulation results verify the effectiveness of the integration of the heat-removal system into the gallium nitride heterostructure field-effect transistor that can mitigate the self-heating effect and improve the device performance. The advantage of our concept is that the graphene heat-eliminating element is structurally connected with a heat sink and is designed for removing the heat immediately from the maximum temperature area through the trench in which a high thermal conductivity material is deposited. The results can be used by the electronics industry of the Republic of Belarus for developing the hardware components of gallium nitride power electronics.

scholarly journals Gallium Nitride Normally-Off Vertical Field-Effect Transistor Featuring an Additional Back Current Blocking Layer Structure

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 241 ◽  
Author(s):  
Huolin Huang ◽  
Feiyu Li ◽  
Zhonghao Sun ◽  
Nan Sun ◽  
Feng Zhang ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Blocking Layer ◽  
Vertical Field ◽  
Current Blocking Layer ◽  
Effect Transistor ◽  
Vertical Field Effect ◽  
Vertical Field Effect Transistor ◽  
Current Blocking

A gallium nitride (GaN) semiconductor vertical field-effect transistor (VFET) has several attractive advantages such as high power density capability and small device size. Currently, some of the main issues hindering its development include the realization of normally off operation and the improvement of high breakdown voltage (BV) characteristics. In this work, a trenched-gate scheme is employed to realize the normally off VFET. Meanwhile, an additional back current blocking layer (BCBL) is proposed and inserted into the GaN normally off VFET to improve the device performance. The electrical characteristics of the proposed device (called BCBL-VFET) are investigated systematically and the structural parameters are optimized through theoretical calculations and TCAD simulations. We demonstrate that the BCBL-VFET exhibits a normally off operation with a large positive threshold voltage of 3.5 V and an obviously increased BV of 1800 V owing to the uniform electric field distribution achieved around the gate region. However, the device only shows a small degradation of on-resistance (RON). The proposed scheme provides a useful reference for engineers in device fabrication work and will be promising for the applications of power electronics.

Nanomembranes: Single Crystal Gallium Nitride Nanomembrane Photoconductor and Field Effect Transistor (Adv. Funct. Mater. 41/2014)

2014 ◽  
Vol 24 (41) ◽  
pp. 6564-6564
Author(s):  
Kanglin Xiong ◽  
Sung Hyun Park ◽  
Jie Song ◽  
Ge Yuan ◽  
Danti Chen ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Single Crystal ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Effect Transistor

A Comparative Numerical Study of Junctionless and p-i-n Tunneling Carbon Nanotube Field Effect Transistor

2017 ◽  
Vol 45 ◽  
pp. 55-75 ◽  
Author(s):  
Rouzbeh Molaei Imen Abadi ◽  
Seyed Ali Sedigh Ziabari
Keyword(s):  
Carbon Nanotube ◽  
Delay Time ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Numerical Study ◽  
Channel Length ◽  
Novel Device ◽  
Device Structures ◽  
Effect Transistor ◽  
Tunnel Field Effect Transistor

In this paper, a gate-all-around junctionless tunnel field effect transistor (JL-TFET) based on carbon nanotube (CNT) material is introduced and simulated. The JL-TFET is a CNT-channel heavily n-type-doped junctionless field effect transistor (JLFET) which utilizes two insulated gates (Control-Gate, P-Gate) with two different metal workfunctions in order to treat like tunnel field effect transistor (TFET). In this design, the privileges of JLTFET and TFET are mixed together. The numerical comparative study on the performance characteristics of JL-TFET and conventional p-i-n TFET demonstrated that the proposed JL-TFET has a higher ON-state current driveability (ION), a larger ON/OFF-current ratio (ION/IOFF), a lower drain induced barrier lowering (DIBL), a shorter delay time (τ), and also a superior cut-off frequency (ƒT). Moreover, in order to further performance improvement of proposed JLTFET, three novel device structures namely as junctionless linear descending gate workfunction TFET (JL-LDWTFET), junctionless linear ascending gate workfunction TFET (JL-LAWTFET) and junctionless triple metal gate TFET (JL-TMGTFET) are proposed by gate workfunction engineering approach. According to simulation results, the JL-TMGTFET with the gate composed of three segments of different work functions shows excellent characteristics with high ION/IOFF ratio, a superior ambipolar characteristic, a shorter delay time and a better cut-off frequency compared to conventional p-i-n TFET and other proposed junctionless-based features. All the simulations are done with the full quantum mechanical simulator for a channel length of 60-nm using nonequilibrium Green’s function (NEGF) method.

The effect of channel uniaxial strain on thermal conductivity of graphene nano-ribbon field effect transistor

2019 ◽  
Vol 33 (01) ◽  
pp. 1850416
Author(s):  
Elham Zonoobi Doyom ◽  
Saeed Haji-Nasiri
Keyword(s):  
Thermal Conductivity ◽  
Band Gap ◽  
Energy Band ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Drain Current ◽  
Channel Length ◽  
Uniaxial Strain ◽  
Energy Band Gap ◽  
Effect Transistor

The effect of channel uniaxial strain on thermal conductivity of graphene nano-ribbon field effect transistor (GNRFET) is analyzed by self-consistent Hückel method. The supposed strains are tensile and its values are 2% to 24% of lattice constant. All of the assumed strains are applied to the channel length direction. Energy band gap, density of states (DOS), phonon transmission, thermal conductivity, and I–V characteristics of the GNRFET have been calculated. The results show that by increasing the strain, the energy band gap of the channel is increased and the drain current is decreased. Also by increasing the band gap, phonon transmission is decreased. Maximum phonon transmission occurs in 8% strain. By considering all of these parameters, the results show that there is a maximum thermal conductivity versus temperature in 8% uniaxial strain that is more than the bare one and its value is decreased intensively in 16% and 24% strain. This is due to maximum phonon transmission that is observed in 8% strain and increasing the DOS around the energy band gap in this value. Also, it is observed that in the energy range of more than 0.75 eV, by increasing the strain, thermal conductivity is increased.

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