scholarly journals Laser Processing of Transparent Wafers with a AlGaN/GaN Heterostructures and High-Electron Mobility Devices on a Backside

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 407
Author(s):  
Simonas Indrišiūnas ◽  
Evaldas Svirplys ◽  
Justinas Jorudas ◽  
Irmantas Kašalynas
Keyword(s):  
Laser Processing ◽  
Electronic Devices ◽  
Laser Micromachining ◽  
Spot Size ◽  
Substrate Thickness ◽  
High Electron ◽  
Thin Coatings ◽  
Transparent Substrate ◽  
Mobility Devices ◽  
Mechanical Cleavage

Sapphire and silicon carbide substrates are used for growth of the III-N group heterostructures to obtain the electronic devices for high power and high frequency applications. Laser micromachining of deep channels in the frontside of the transparent wafers followed by mechanical cleavage along the ablated trench is a useful method for partitioning of such substrates after the development of the electronics on a backside. However, in some cases damage to the component performance occurs. Therefore, the influence of various parameters of the laser processing, such as fluence in the spot size, substrate thickness, orientation, and the polarization of focused laser beam, to the formation of damage zones at both sides of the transparent substrate with thin coatings when ablating the trenches from one side was investigated. The vicinity effect of the ablated trenches on the performance of the electronics was also evaluated, confirming the laser micromachining suitability for the dicing of transparent wafers with high accuracy and flexibility.

scholarly journals The Evolution of Manufacturing Technology for GaN Electronic Devices

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 737
Author(s):  
An-Chen Liu ◽  
Po-Tsung Tu ◽  
Catherine Langpoklakpam ◽  
Yu-Wen Huang ◽  
Ya-Ting Chang ◽  
...  
Keyword(s):  
Mobile Communications ◽  
High Power ◽  
Electronic Devices ◽  
High Volume ◽  
Cmos Technology ◽  
High Electron ◽  
Process Technology ◽  
Unit Process ◽  
Rf Power Amplifier ◽  
Device Technology

GaN has been widely used to develop devices for high-power and high-frequency applications owing to its higher breakdown voltage and high electron saturation velocity. The GaN HEMT radio frequency (RF) power amplifier is the first commercialized product which is fabricated using the conventional Au-based III–V device manufacturing process. In recent years, owing to the increased applications in power electronics, and expanded applications in RF and millimeter-wave (mmW) power amplifiers for 5G mobile communications, the development of high-volume production techniques derived from CMOS technology for GaN electronic devices has become highly demanded. In this article, we will review the history and principles of each unit process for conventional HEMT technology with Au-based metallization schemes, including epitaxy, ohmic contact, and Schottky metal gate technology. The evolution and status of CMOS-compatible Au-less process technology will then be described and discussed. In particular, novel process techniques such as regrown ohmic layers and metal–insulator–semiconductor (MIS) gates are illustrated. New enhancement-mode device technology based on the p-GaN gate is also reviewed. The vertical GaN device is a new direction of development for devices used in high-power applications, and we will also highlight the key features of such kind of device technology.

scholarly journals Development of AlGaN/GaN/SiC high-electron-mobility transistors for THz detection

2018 ◽  
Vol 58 (2) ◽  
Author(s):  
Vytautas Jakštas ◽  
Justinas Jorudas ◽  
Vytautas Janonis ◽  
Linas Minkevičius ◽  
Irmantas Kašalynas ◽  
...  
Keyword(s):  
Electron Mobility ◽  
Schottky Diodes ◽  
Electronic Devices ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
High Electron Mobility ◽  
Gan Hemt ◽  
Electron Mobility Transistors ◽  
Steady Current ◽  
Improved Performance

This paper reports on the AlGaN/GaN Schottky diodes (SDs) and high-electron-mobility transistors (HEMTs) grown on a semi-insulating SiC substrate. The electronic devices demonstrate an improved performance in comparison with the ones processed on a sapphire substrate. Both the SDs and HEMTs show much smaller leakage current density and a higher ION/IOFF ratio, reaching values down to 3.0±1.2 mA/cm2 and up to 70 dB under the reverse electric field of 340 kV/cm, respectively. The higher thermal conductivity of the SiC substrate leads to the increase of steady current and transconductance, and better thermal management of the HEMT devices. In addition, a successful detection of terahertz (THz) waves with the AlGaN/GaN HEMT is demonstrated at room temperature. These results open further routes for the optimization of THz designs which may result in development of novel plasmonic THz devices.

Boron Nitride as a Passivation Capping Layer for AlGaN/GaN High Electron Mobility Transistors

2020 ◽  
Vol 20 (7) ◽  
pp. 4450-4453 ◽  
Author(s):  
Gun Hee Lee ◽  
Ah Hyun Park ◽  
Jin Hong Lim ◽  
Chil-Hyoung Lee ◽  
Dae-Woo Jeon ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Electron Mobility ◽  
Hexagonal Boron Nitride ◽  
Electronic Devices ◽  
Charge Trapping ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
High Electron Mobility ◽  
Capping Layer ◽  
Electron Mobility Transistors

We report on the electrical characteristics of AlGaN/GaN high-electron mobility transistors (HEMTs) with hexagonal boron nitride (h-BN) as a passivation capping layer. The HEMTs with h-BN layers showed an increase in current drainage and 103-times reduction in the gate-leakage current compared with those of conventional unpassivated HEMTs. Moreover, the extrinsic transconductance and the pulse responses were improved due to the reduced charge-trapping effect at the surface of HEMTs. From our observations, the h-BN can be used as a passivation capping layer for high-power electronic devices.

The WS2 dependence on the elasticity and optical band gap energies of swollen PAAm composites

2020 ◽  
Vol 55 (1) ◽  
pp. 71-76
Author(s):  
Gülşen Akın Evingür ◽  
Nafia Alara Sağlam ◽  
Büşra Çimen ◽  
Bengü Özuğur Uysal ◽  
Önder Pekcan
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Polymer Composites ◽  
Optical Band Gap ◽  
Electronic Devices ◽  
Band Gap Energy ◽  
Tungsten Disulfide ◽  
High Electron ◽  
New Generation ◽  
Doped Polymer

New generation nano-filler polymer composites have many applications including biomedical, electronic and maritime related applications because of their mechanical, electronic and optical properties. The properties of composites were investigated as a function of nano-filler content. Among these, tungsten disulfide (WS2) has the potential to be used as a component in electronic devices owing to its high electron mobility and easily tunable optical band gap energy. Tungsten disulfide (WS2)- Polyacrylamide (PAAm) composite was prepared using free radical co-polymerization and wet laboratory methods with WS2 content. Composites were characterized for mechanical and optical properties using an Elasticity Instrument and UV-vis Spectrophotometer, respectively. Elastic modulus was modeled by a statistical thermodynamics model. Tauc’s and Urbach’s Tail model for direct transition were used to model for the optical band gap. In this study, the swelling and WS2 effect on the optical band gap and elasticity of WS2 - PAAm composites were investigated. It was observed that the elasticity presented a reversed behavior of optical band gap energies with respect to WS2 content. For the applications of nano-filler doped polymer composites in flexible electronic devices, WS2 content strongly influences the mechanical and optical properties.

Computer Simulation of Laser Induced Temperatures for the Laser Direct Writing technique

1987 ◽  
Vol 101 ◽  
Author(s):  
Didier Tonneau ◽  
Geoffroy Auvert
Keyword(s):  
Laser Power ◽  
Quartz Substrate ◽  
Equilibrium Temperature ◽  
Spot Size ◽  
Heat Diffusion ◽  
Laser Spot ◽  
Maximum Temperature ◽  
Substrate Thickness ◽  
Direct Writing ◽  
Gaussian Laser Beam

ABSTRACTLaser induced temperatures in substrates irradiated with a scanning gaussian laser beam were calculated by the finite element method. A quartz substrate of a given thickness and covered with a one - micron - thick silicon coating was assumed to be either placed on a heat sink or thermally insulated. The maximum temperature in the center of the laser spot was found to be proportional to the laser power for a spot size larger than the silicon thickness. Furthermore at a given laser power, the temperature decreased with increasing laser spot diameter and the time to reach the equilibrium temperature increases with the spot radius for radii less than the substrate thickness. The laser induced temperature was found to be affected by laser - scan speeds for speed values above the heat diffusion rate.

Development of a Processing Window for the Transformation Hardening of Nickel-Aluminium-Bronze

2010 ◽  
Vol 654-656 ◽  
pp. 1916-1919 ◽  
Author(s):  
Ryan Cottam ◽  
Milan Brandt
Keyword(s):  
Laser Processing ◽  
Laser Power ◽  
Processing Parameters ◽  
Spot Size ◽  
Good Combination ◽  
Transfer Model ◽  
Laser Spot Size ◽  
Processing Window ◽  
Aluminium Bronze ◽  
Marine Applications

Nickel-Aluminium-Bronzes (NAB) are typically used in marine applications because of their good combination of corrosion resistance and strength. Even though these alloys exhibit good properties they do suffer from wear, corrosion, dealloying, cavitation corrosion-erosion or corrosion fatigue during service. Therefore methods of increasing the resistance of this class of alloy to surface sensitive damage mechanisms are desirable. Transformation hardening through laser processing offers the potential to increase the resistance of these alloys surface sensitive mechanisms of damage and increase their life. A processing window has been developed through the use of an analytical heat transfer model to determine laser processing parameters that are close to the critical temperature for surface melting. The absorption of the laser by NAB has been determined and the processing window calculated taking into account the velocity of the laser, laser spot size and type as well as laser power.

scholarly journals Hexacoordinated Gallium(III) Triazenide Precursor for Epitaxial Gallium Nitride by Atomic Layer Deposition

2020 ◽  
Author(s):  
Polla Rouf ◽  
Rouzbeh Samii ◽  
Karl Rönnby ◽  
Babak Bakhit ◽  
Sydney Buttera ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Atomic Layer Deposition ◽  
Electronic Devices ◽  
Atomic Layer ◽  
High Electron Mobility Transistor ◽  
Deposition Process ◽  
Single Step ◽  
High Electron ◽  
High Quality ◽  
Layer Deposition

Gallium nitride (GaN) is the main component of modern-day high electron mobility transistor electronic devices due to its favorable electronic properties. As electronic devices become smaller with more complex architecture, the ability to deposit high-quality GaN films at low temperature is required. Herein, we report a new highly volatile Ga(III) triazenide precursor and demonstrate its ability to deposit high-quality epitaxial GaN by atomic layer deposition (ALD). This new Ga(III) triazenide precursor, the first hexacoordinated M–N bonded Ga(III) precursor used in a vapor deposition process, was easily synthesized and purified by sublimation. Thermogravimetric analysis showed single step volatilization with an onset temperature of 150 °C and negligible residual mass. Three temperature intervals with self-limiting growth were observed when depositing GaN films. In the second growth interval, the films were found to be near stoichiometric with very low levels of impurities and epitaxial orientation on 4H-SiC without an AlN seed layer. The films grown at 350 °C were found to be smooth with a sharp interface between the substrate and film. The bandgap of these films was 3.41 eV with the Fermi level at 1.90 eV, showing that the GaN films were unintentionally <i>n</i>-type doped. This new triazenide precursor enables ALD of GaN for semiconductor applications and provides a new Ga(III) precursor for future deposition processes.

scholarly journals Drude–Lorentz Model for Optical Properties of Photoexcited Transition Metals under Electron–Phonon Nonequilibrium

2021 ◽  
Vol 11 (21) ◽  
pp. 9902
Author(s):  
Elena Silaeva ◽  
Louis Saddier ◽  
Jean-Philippe Colombier
Keyword(s):  
Optical Properties ◽  
Transition Metals ◽  
Laser Processing ◽  
Laser Excitation ◽  
Laser Surface ◽  
High Electron ◽  
Ab Initio Methods ◽  
Lorentz Model ◽  
Basin Hopping ◽  
Shed Light

Evaluating the optical properties of matter under the action of ultrafast light is crucial in modeling laser–surface interaction and interpreting laser processing experiments. We report optimized coefficients for the Drude–Lorentz model describing the permittivity of several transition metals (Cr, W, Ti, Fe, Au, and Ni) under electron–phonon nonequilibrium, with electrons heated up to 30,000 K and the lattice staying cold at 300 K. A Basin-hopping algorithm is used to fit the Drude–Lorentz model to the nonequilibrium permittivity calculated using ab initio methods. The fitting coefficients are provided and can be easily inserted into any calculation requiring the optical response of the metals during ultrafast irradiation. Moreover, our results shed light on the electronic structure modifications and the relative contributions of intraband and interband optical transitions at high electron temperatures corresponding to the laser excitation fluence used for surface nanostructuring.

High electron mobility and transverse negative magnetoresistance in van der Waals material Nb2GeTe4

2021 ◽  
Author(s):  
Xue Han ◽  
Zhongnan Guo ◽  
Long Chen ◽  
Cheng Cao ◽  
Fan Sun ◽  
...  
Keyword(s):  
Carrier Mobility ◽  
Electronic Devices ◽  
Charge Carrier Mobility ◽  
Single Crystal Growth ◽  
High Electron ◽  
Two Dimensional ◽  
High Electron Mobility ◽  
Quantum Properties ◽  
2D Semiconductors ◽  
High Charge Carrier Mobility

Two-dimensional (2D) semiconductors with high charge-carrier mobility and exotic quantum properties are of great importance for design of the outstanding electronic devices. Here we report the single crystal growth of...

Sign in / Sign up

Export Citation Format

Share Document