Recessed gate GaN MESFETs fabricated by the photoelectrochemical etching process

1999 ◽  
Vol 572 ◽  
Author(s):  
Won Sang Lee ◽  
Yoon Ho Choi ◽  
Ki Woong Chung ◽  
Moo Whan Shin ◽  
Dong Chan Moon
Keyword(s):  
Electrochemical Etching ◽  
Etching Rate ◽  
Drain Current ◽  
Etching Process ◽  
Device Performance ◽  
High Activation ◽  
Band Bending ◽  
Photoelectrochemical Etching ◽  
Characteristic Frequencies ◽  
Recessed Gate

ABSTRACTA new photo-electrochemical etching method was developed and used to fabricate GaN MESFETs. The etching process uses photoresist for masking illumination and the etchant is KOH based. The etching rate with 1.0 mol% of KOH for n-GaN is as high as 1600 Å/min under the Hg illumination of 35 mW/cm/2. The MESFET saturates at VDS = 4 V and pinches off at VGS = −3 V. The maximum drain current of the device is 230 mA/mmn at 300 K and the value is remained almost same for 500 K operation. The characteristic frequencies, fT and fmax, are 6.35 GHz and 10.25 GHz, respectively. Insensitivity of the device performance to temperature was attributed to the defect-related high activation energy of dopants for ionization and band-bending at the subgrain boundaries in GaN thin films.

High temperature performance of recessed gate GaN MESFETs fabricated using photoelectrochemical etching process

2000 ◽  
Vol 36 (3) ◽  
pp. 265 ◽  
Author(s):  
Won Sang Lee ◽  
Yoon Ho Choi ◽  
Ki Woong Chung ◽  
Dong Chan Moon ◽  
Moo Whan Shin
Keyword(s):  
High Temperature ◽  
Etching Process ◽  
Photoelectrochemical Etching ◽  
Temperature Performance ◽  
Recessed Gate

High-current recessed gate enhancement-mode ultrawide bandgap Al x Ga1−x N channel MOSHFET with drain current 0.48 A mm−1 and threshold voltage +3.6 V

2021 ◽  
Vol 14 (1) ◽  
pp. 014003
Author(s):  
Shahab Mollah ◽  
Kamal Hussain ◽  
Abdullah Mamun ◽  
Mikhail Gaevski ◽  
Grigory Simin ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Drain Current ◽  
High Current ◽  
Enhancement Mode ◽  
Recessed Gate

Well-controlled preparation of evenly distributed nanoporous HOPG surface via diazonium salt assisted electrochemical etching process

Carbon ◽  
2016 ◽  
Vol 102 ◽  
pp. 419-425 ◽  
Author(s):  
Liang Cui ◽  
Yuanhong Xu ◽  
Bingping Liu ◽  
Wenrong Yang ◽  
Zhongqian Song ◽  
...  
Keyword(s):  
Electrochemical Etching ◽  
Diazonium Salt ◽  
Etching Process ◽  
Controlled Preparation

213 W 500 Mhz 4H-SiC Static Induction Transistor

2011 ◽  
Vol 130-134 ◽  
pp. 3392-3395 ◽  
Author(s):  
Gang Chen ◽  
Peng Wu ◽  
Song Bai ◽  
Zhe Yang Li ◽  
Yun Li ◽  
...  
Keyword(s):  
Current Density ◽  
Drain Current ◽  
Total Power ◽  
Class Ab ◽  
Blocking Voltage ◽  
Finger Width ◽  
Static Induction Transistor ◽  
Recessed Gate ◽  
Total Power Output ◽  
A Current

. Silicon carbide (SiC) SITs were fabricated using home-grown epi structures. The gate is a recessed gate - bottom contact (RG - B). We designed that the mesa space 2.7μm and the gate channel is 1.2μm. One cell has 400 source fingers and each source finger width is 100μm. 1mm SiC SIT yielded a current density of 123mA/mm of drain current at a drain voltage of 20V. A maximum current density of 150 mA/mm was achieved with Vd=40V. The device blocking voltage with a gate bias of-16 V was 200 V. Packaged 24-cm devices were evaluated using amplifier circuits designed for class AB operations. A total power output in excess of 213 W was obtained with a power density of 8.5 W/cm and gain of 8.5 dB at 500 MHz under pulse operation.

scholarly journals Dry Etching of Germanium with Laser Induced Reactive Micro Plasma

2021 ◽  
Author(s):  
Martin Ehrhardt ◽  
Pierre Lorenz ◽  
Jens Bauer ◽  
Robert Heinke ◽  
Mohammad Afaque Hossain ◽  
...  
Keyword(s):  
Ion Beam ◽  
Etching Rate ◽  
Dry Etching ◽  
Etching Process ◽  
High Tech ◽  
Etching Time ◽  
High Quality ◽  
Machined Surface ◽  
Reactive Plasma ◽  
New Processing

AbstractHigh-quality, ultra-precise processing of surfaces is of high importance for high-tech industry and requires a good depth control of processing, a low roughness of the machined surface and as little as possible surface and subsurface damage but cannot be realized by laser ablation processes. Contrary, electron/ion beam, plasma processes and dry etching are utilized in microelectronics, optics and photonics. Here, we have demonstrated a laser-induced plasma (LIP) etching of single crystalline germanium by an optically pumped reactive plasma, resulting in high quality etching. A Ti:Sapphire laser (λ = 775 nm, EPulse/max. = 1 mJ, t = 150 fs, frep. = 1 kHz) has been used, after focusing with a 60 mm lens, for igniting a temporary plasma in a CF4/O2 gas at near atmospheric pressure. Typical etching rate of approximately ~ 100 nm / min and a surface roughness of less than 11 nm rms were found. The etching results were studied in dependence on laser pulse energy, etching time, and plasma – surface distance. The mechanism of the etching process is expected to be of chemical nature by the formation of volatile products from the chemical reaction of laser plasma activated species with the germanium surface. This proposed laser etching process can provide new processing capabilities of materials for ultra—high precision laser machining of semiconducting materials as can applied for infrared optics machining.

scholarly journals Simulation Study of the Use of AlGaN/GaN Ultra-Thin-Barrier HEMTs with Hybrid Gates for Achieving a Wide Threshold Voltage Modulation Range

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 654
Author(s):  
Shouyi Wang ◽  
Qi Zhou ◽  
Kuangli Chen ◽  
Pengxiang Bai ◽  
Jinghai Wang ◽  
...  
Keyword(s):  
Hole Concentration ◽  
Drain Current ◽  
Device Performance ◽  
Depletion Effect ◽  
Threshold Voltages ◽  
Gate Structure ◽  
Drain Side ◽  
Effective Reduction ◽  
Field Peak ◽  
Thin Barrier

In this work, novel hybrid gate Ultra-Thin-Barrier HEMTs (HG-UTB HEMTs) featuring a wide modulation range of threshold voltages (VTH) are proposed. The hybrid gate structure consists of a p-GaN gate part and a MIS-gate part. Due to the depletion effect assisted by the p-GaN gate part, the VTH of HG-UTB HEMTs can be significantly increased. By tailoring the hole concentration of the p-GaN gate, the VTH can be flexibly modulated from 1.63 V to 3.84 V. Moreover, the MIS-gate part enables the effective reduction in the electric field (E-field) peak at the drain-side edge of the p-GaN gate, which reduces the potential gate degradation originating from the high E-field in the p-GaN gate. Meanwhile, the HG-UTB HEMTs exhibit a maximum drain current as high as 701 mA/mm and correspond to an on-resistance of 10.1 Ω mm and a breakdown voltage of 610 V. The proposed HG-UTB HEMTs are a potential means to achieve normally off GaN HEMTs with a promising device performance and featuring a flexible VTH modulation range, which is of great interest for versatile power applications.

scholarly journals Fabrication of (ZnO)x: (Cu)1-x/PSi Solar Cell Using Laser Induced Plasma Technique

2021 ◽  
Vol 2114 (1) ◽  
pp. 012028
Author(s):  
G. H. Jihad ◽  
K.A. Aadim
Keyword(s):  
Solar Cell ◽  
Electrical Properties ◽  
Current Density ◽  
Electrochemical Etching ◽  
Average Diameter ◽  
Etching Process ◽  
Morphological Properties ◽  
Etching Time ◽  
Solar Cell Performance ◽  
Cell Efficiency

Abstract Fabrication of PSi is generated successfully depending upon photo-electrochemical etching process. The purpose is to differentiate the characterization of the PSi monolayer based on c-silicon solar cell compared to the bulk silicon alone. The surface of ordinary p-n solar cell has been reconstructed on the n-type region of (100) orientation with resistivity (3.2.cm) in hydrofluoric (HF) acid at a concentration of 2 ml was used to in order to enhance the conversion efficiency with 10-minute etching time and current density of 50 mA/cm2, The morphological properties (AFM) as well as the electrical properties have been investigated (J-V). The atomic force microscopy investigation reveals a rugged silicon surface with porous structure nucleating during the etching process (etching time), resulting in an expansion in depth and an average diameter of (40.1 nm). As a result, the surface roughness increases. The electrical properties of prepared PS, namely current density-voltage characteristics in the dark, reveal that porous silicon has a sponge-like structure and that the pore diameter increases with increasing etching current density and the number of shots increasing this led that the solar cell efficiency was in the range of (1-2%), resulting in improved solar cell performance.

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