Microwave performance of recessed gate Al0.2Ga0.8N/GaN HFETs fabricated using a photoelectrochemical etching technique

2002 ◽  
Vol 95 (1) ◽  
pp. 73-76 ◽  
Author(s):  
Jong-Wook Kim ◽  
Jae-Seung Lee ◽  
Won-Sang Lee ◽  
Jin-Ho Shin ◽  
Doo-Chan Jung ◽  
...  
Keyword(s):  
Etching Technique ◽  
Photoelectrochemical Etching ◽  
Recessed Gate

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.

scholarly journals Preparation of Nanorod Structure of TiO2 by the Use of Photoelectrochemical Etching Technique

2004 ◽  
Vol 77 (2) ◽  
pp. 64-68 ◽  
Author(s):  
Takashi SUGIURA ◽  
Han Jin RYU ◽  
Satoshi YASUNO ◽  
Hideki MINOURA
Keyword(s):  
Etching Technique ◽  
Photoelectrochemical Etching

A Damage-Reduced Process Revealed by Photoluminescence in Photoelectrochemical Etching GaN

1999 ◽  
Vol 595 ◽  
Author(s):  
J. M. Hwang ◽  
J. T. Hsieh ◽  
H. L. Hwang ◽  
W. H. Hung
Keyword(s):  
Chemical Etching ◽  
Variable Temperature ◽  
Treatment Method ◽  
Yellow Luminescence ◽  
Etching Technique ◽  
Photoelectrochemical Etching ◽  
Shallow Acceptor ◽  
Novel Technique ◽  
Deep Donor

AbstractPhotoelectrochemical (PEC) etching technique has been proven to be an effective method to etch GaN. Despite its success, investigations on etching-induced damage are still scare. In this work, the damage induced by PEC etching of GaN in KOH electrolyte was studied. Photoluminescence (PL) spectroscopy was used to explore the origin of etching-induced damaged layer. From the variable temperature PL measurements, the origin of etching-induced damage was attributed to be the defect complex of VGa-ON (gallium vacancy bonds to oxygeon on nitrogen antisite). With determination of the defect origin, the electronic transition in the etch damage-related yellow luminescence (YL) band was suggested to be deep donor-like state to shallow-acceptor transition. In addition, a post-treatment method with boiled KOH chemical etching was developed to remove the thin damaged layer. In this method, crystallographic etching characteristics of boiled KOH was observed to assist in the formation of smooth sidewall facets. As revealed by the reduction of yellow luminescence, we propose this novel technique as a near damage-free etching method.

scholarly journals A damage-reduced process revealed by photoluminescence in photoelectrochemical etching GaN

2000 ◽  
Vol 5 (S1) ◽  
pp. 873-879 ◽  
Author(s):  
J. M. Hwang ◽  
J. T. Hsieh ◽  
H. L. Hwang ◽  
W. H. Hung
Keyword(s):  
Chemical Etching ◽  
Variable Temperature ◽  
Treatment Method ◽  
Yellow Luminescence ◽  
Etching Technique ◽  
Photoelectrochemical Etching ◽  
Shallow Acceptor ◽  
Novel Technique ◽  
Deep Donor

Photoelectrochemical (PEC) etching technique has been proven to be an effective method to etch GaN. Despite its success, investigations on etching-induced damage are still scare. In this work, the damage induced by PEC etching of GaN in KOH electrolyte was studied. Photoluminescence (PL) spectroscopy was used to explore the origin of etching-induced damaged layer. From the variable temperature PL measurements, the origin of etching-induced damage was attributed to be the defect complex of VGa-ON (gallium vacancy bonds to oxygeon on nitrogen antisite). With determination of the defect origin, the electronic transition in the etch damage-related yellow luminescence (YL) band was suggested to be deep donor-like state to shallow-acceptor transition. In addition, a post-treatment method with boiled KOH chemical etching was developed to remove the thin damaged layer. In this method, crystallographic etching characteristics of boiled KOH was observed to assist in the formation of smooth sidewall facets. As revealed by the reduction of yellow luminescence, we propose this novel technique as a near damage-free etching method.

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

Single-Crystal SiC Resonators by Photoelectrochemical Etching

2012 ◽  
Vol 717-720 ◽  
pp. 529-532 ◽  
Author(s):  
Mohammad M. Islam ◽  
Chih Fang Huang ◽  
Feng Zhao
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Chemical Properties ◽  
Etching Technique ◽  
Scanning Method ◽  
Photoelectrochemical Etching ◽  
Resonant Structures ◽  
Single Crystal Sic ◽  
Dynamic Scanning ◽  
And Chemical Properties

In this paper, we report single-crystal 4H-SiC resonant structures fabricated by dopant-selective photoelectrochemical etching. The frequency response of the resonant beams was characterized by a dynamic scanning method using AFM with the beams excited by a piezoelectric actuator under atmosphere pressure and room temperature. The beam with a length of 35 μm shows mechanical resonance at 945 kHz. The Young’s modulus of single-crystal SiC was derived from the measured resonant frequency. Single-crystal 4H-SiC resonators developed in this study fully exploit the excellent electrical, mechanical, and chemical properties of SiC, while dopant-selective photoelectrochemical etching technique significantly simplifies the fabrication process.

The Formation, Structure, Distribution and Frequency of Nuclear Pores

1971 ◽  
Vol 29 ◽  
pp. 518-519
Author(s):  
G. G. Maul
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Dynamic Structure ◽  
Nuclear Pore ◽  
Nuclear Pores ◽  
Filter Function ◽  
Etching Technique ◽  
Selective Filter ◽  
Membranous Part

The chromatin of eukaryotic cells is separated from the cytoplasm by a double membrane. One obvious structural specialization of the nuclear membrane is the presence of pores which have been implicated to facilitate the selective nucleocytoplasmic exchange of a variety of large molecules. Thus, the function of nuclear pores has mainly been regarded to be a passive one. Non-membranous diaphragms, radiating fibers, central rings, and other pore-associated structures were thought to play a role in the selective filter function of the nuclear pore complex. Evidence will be presented that suggests that the nuclear pore is a dynamic structure which is non-randomly distributed and can be formed during interphase, and that a close relationship exists between chromatin and the membranous part of the nuclear pore complex.Octagonality of the nuclear pore complex has been confirmed by a variety of techniques. Using the freeze-etching technique, it was possible to show that the membranous part of the pore complex has an eight-sided outline in human melanoma cells in vitro. Fibers which traverse the pore proper at its corners are continuous and indistinguishable from chromatin at the nucleoplasmic side, as seen in conventionally fixed and sectioned material. Chromatin can be seen in octagonal outline if serial sections are analyzed which are parallel but do not include nuclear membranes (Fig. 1). It is concluded that the shape of the pore rim is due to fibrous material traversing the pore, and may not have any functional significance. In many pores one can recognize a central ring with eight fibers radiating to the corners of the pore rim. Such a structural arrangement is also found to connect eight ribosomes at the nuclear membrane.

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