Selective wet etching for highly uniform GaAs/Al0.15Ga0.85As heterostructure field effect transistors

Kitano, Toshiaki; Izumi, Satoshi; Matsuda, Hiroyuki; Ishikawa, Tomohiro; Sato, Kanta; Sonoda, T.; Otsubo, M.

doi:10.1116/1.589243

Cited by 24 publications

(5 citation statements)

References 5 publications

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“…Some reports discussed the influence of gate recess dry etching in HEMTs [1,2]. Recently, highly selective chemical wet etching was developed and used for gate recessing of HEMTs for avoiding plasma damage [3][4][5]. Even then, we were aware of the degradation of carrier density and electron mobility in P-HEMTs by our experience.…”

Section: Introductionmentioning

confidence: 89%

Plasma-Induced Fluorine Damage in P-HEMT Caused by C2F6/CHF3 RIE Plasma

Uchiyama

Taniguchi

2004

IEICE Electron. Express

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Fluorine atoms intruded into the channel layer in P-HEMT and degraded its carrier density and electron mobility during the SiO 2 RIE process. Thermal annealing at 300 • C for 10 minutes was rather effective for recovering from this plasma damage. Our SIMS investigation revealed that the mechanism of this recovery was the removal of fluorine atoms from the channel layer and their accumulation in the δ-doped Si layer. Ionized impurities in the channel layer were removed, and electron mobility was significantly recovered. However, the carrier density was recovered to a lesser degree than that of the electron mobility because of the neutralization of Si donors in the δ-doped layer caused by the fluorine accumulation.

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Section: Introductionmentioning

confidence: 89%

Plasma-Induced Fluorine Damage in P-HEMT Caused by C2F6/CHF3 RIE Plasma

Uchiyama

Taniguchi

2004

IEICE Electron. Express

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“…The selectivity of GaAs and AlGaAs with present NH 4 OH/H 2 O 2 mixture is usually several tens to hundreds, 19 and could be improved by optimization of the etching. Note that these nanotubes are another proof of the formation of core-shell nanowires from SA-MOVPE and simple etching processes.…”

Section: -mentioning

confidence: 99%

Fabrication and characterization of freestanding GaAs∕AlGaAs core-shell nanowires and AlGaAs nanotubes by using selective-area metalorganic vapor phase epitaxy

Noborisaka

Motohisa

Hara

et al. 2005

Applied Physics Letters

185

172

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We fabricated GaAs/ AlGaAs core-shell nanowires by using selective-area metalorganic vapor phase epitaxy. First, GaAs nanowires were selectively grown on partially masked GaAs ͑111͒B substrates; then AlGaAs was grown to form freestanding heterostructured nanowires. Investigation of nanowire diameter as a function of AlGaAs growth time suggested that the AlGaAs was grown on the sidewalls of the GaAs nanowires, forming GaAs/ AlGaAs core-shell structures. Microphotoluminescence measurements of GaAs and GaAs/ AlGaAs core-shell nanowires reveal an enhancement of photoluminescence intensity in GaAs/ AlGaAs core-shell structures. Based on these core-shell nanowires, AlGaAs nanotubes were formed by using anisotropic dry etching and wet chemical preferential etching to confirm the formation of a core-shell structure and to explore a new class of materials.

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“…Definition of the resonator geometry in the Al x Ga 1−x As epilayers relies on electron cyclotron resonance etching through the mirror stack using Cl 2 /Ar, with masking provided by the resist/SiN x . To undercut the cantilevers, a buffered citric acid solution is utilized [28]. This selective wet etch allows for the removal of the binary GaAs, in this case the substrate, over the low-aluminum content ternary Al 0.12 Ga 0.88 As layers with excellent selectivity [26].…”

mentioning

confidence: 99%

Monocrystalline AlxGa1−xAs heterostructures for high-reflectivity high-Q micromechanical resonators in the megahertz regime

Cole

Gröblacher

Gugler

et al. 2008

Applied Physics Letters

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We present high-performance megahertz micromechanical oscillators based on freestanding epitaxial AlxGa1−xAs distributed Bragg reflectors. Compared with dielectric reflectors, the low mechanical loss of the monocrystalline heterostructure gives rise to significant improvements in the achievable mechanical quality factor Q while simultaneously exhibiting near unity reflectivity. Experimental characterization yields an optical reflectivity exceeding 99.98% and mechanical quality factors up to 20 000 at 4 K. This materials system is not only an interesting candidate for optical coatings with ultralow thermal noise, but also provides a promising path towards quantum optical control of massive micromechanical mirrors [1].High-quality Bragg mirrors with small mechanical dissipation have generated recent interest due to their versatile use in both fundamental and applied sciences. Specifically, mechanical dissipation in optical coatings is known to limit the performance of high-finesse cavity applications, in particular gravitational wave interferometry [2] and laser frequency stabilization for optical clocks [3], because of residual phase noise, also referred to as coating thermal noise [4]. On the other hand, microstructures of high mechanical and optical quality have become a leading candidate to achieve quantum optical control of mechanical systems. One specific goal in this emerging field of quantum optomechanics is to combine the concepts of cavity quantum optics with radiation-pressure coupling to generate and detect quantum states of massive mechanical systems such as the quantum ground state [5,6,7] or even entangled quantum states [8,9,10]. The recent demonstrations of cavity-assisted laser-cooling of mechanical modes [11,12,13,14] can be considered an important milestone in this direction.Most of these schemes rely crucially on mechanical structures that combine both high optical reflectivity R and low mechanical dissipation, i.e. a high quality factor Q of the mechanical mode of interest. In addition, entering the quantum regime will require operation in the so-called sideband-limited regime [5,6,7], in which the cavity bandwidth of the optomechanical device is much smaller than the mechanical resonance frequency. [18], the mechanical quality factor of free-standing DBRs is limited to below 3000 due to internal losses in the Ta 2 O 5 layers [19]. It is interesting to note that the low Q-value obtained with these devices is consistent with the coating loss angles observed in the LIGO studies of gravitational wave detector coatings of the same material [2,4]. On the other hand, the use of SiO 2 /TiO 2 -based DBRs has led to the demonstration of mechanical quality factors approaching 10 000 at room temperature [12]; there, however, optical absorption in TiO 2 at 1064 nm both limits the reflectivity and results in residual photothermal effects.The concept outlined here seeks to improve upon these previous works by fabricating the oscillator directly from a single-crystal Bragg reflector. In particular, the use...

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Selective wet etching for highly uniform GaAs/Al0.15Ga0.85As heterostructure field effect transistors

Cited by 24 publications

References 5 publications

Plasma-Induced Fluorine Damage in P-HEMT Caused by C2F6/CHF3 RIE Plasma

Plasma-Induced Fluorine Damage in P-HEMT Caused by C2F6/CHF3 RIE Plasma

Fabrication and characterization of freestanding GaAs∕AlGaAs core-shell nanowires and AlGaAs nanotubes by using selective-area metalorganic vapor phase epitaxy

Monocrystalline AlxGa1−xAs heterostructures for high-reflectivity high-Q micromechanical resonators in the megahertz regime

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