Determination of Nano Fluctuations in Surface Oxides of GaSb With Br-IBAE

2003 ◽  
Vol 786 ◽  
Author(s):  
K. Krishnaswami ◽  
B. Krejca ◽  
S.R. Vangala ◽  
C. Santeufemio ◽  
L.P. Allen ◽  
...  

ABSTRACTHigh-quality substrates with thin uniform oxide layers are critical to the development of low-power epitaxy-based GaSb electronic and electro-optic devices. In this material system, the thickness and elemental composition of the oxide layers are a strong function of the surface preparation method. Here, a figure of merit for quantifying the thickness and thickness variations of an oxide layer on GaSb has been developed using bromine ion beam assisted etching (Br-IBAE). Furthermore, the overall thickness and composition of the oxide determines the etch depth for a fixed set of Br-IBAE parameters. The etch rate in GaSb was determined to be ∼395nm/min and that of its surface oxides was measured to be between 1.86 to 4.2nm/min. Hence, due to the difference in etch rates, nano fluctuations of the oxide thickness at the oxide surface and at the substrate/oxide interface, result in amplified roughness fluctuations in the etched GaSb substrate. The average roughness of Br-IBAE etched surfaces is used as figures of merit to quantify the uniformity and smoothness of the oxide layer. To demonstrate this, GaSb surfaces with various oxide layers and thicknesses were identically etched and their surface roughness measured using atomic force microscopy (AFM). This novel technique can generally be extended to a number of material systems.

2000 ◽  
Vol 15 (2) ◽  
pp. 546-553 ◽  
Author(s):  
S. A. Syed Asif ◽  
K. J. Wahl ◽  
R. J. Colton

In this article we report the influence of surface oxides and relative humidity on the nanomechanical response of hydrophobic and hydrophilic Si surfaces. Depth-sensing nanoindentation combined with force modulation enabled measurement of surface forces, surface energy, and interaction stiffness prior to contact. Several regimes of contact were investigated: pre-contact, apparent contact, elastic contact, and elasto-plastic contact. Both humidity and surface preparation influenced the surface mechanical properties in the pre- and apparent-contact regimes. Meniscus formation was observed for both hydrophobic and hydrophilic surfaces at high humidity. Influence of humidity was much less pronounced on hydrophobic surfaces and was fully reversible. In the elastic and elasto-plastic regimes, the mechanical response was dependent on oxide layer thickness. Irreversibility at small loads (300 nN) was due to the deformation of the surface oxide. Above 1 μN, the deformation was elastic until the mean contact pressure reached 11 GPa, whereby Si underwent a pressure-induced phase transformation resulting in oxide layer pop-in and breakthrough. The critical load required for pop-in was dependent on oxide thickness and tip radius. For thicker oxide layers, substrate influence was reduced and plastic deformation occurred within the oxide film itself without pop-in. Elastic modulus and hardness of both the oxide layer and Si substrate were measured quantitatively for depths <5 nm.


2003 ◽  
Vol 792 ◽  
Author(s):  
K. Krishnaswami ◽  
S.R. Vangala ◽  
B. Krejca ◽  
L.P. Allen ◽  
C. Santeufemio ◽  
...  

ABSTRACTGas Cluster Ion Beam (GCIB) processing has recently emerged as a novel surface smoothing technique to improve the finish of chemical-mechanical polished (CMP) GaSb (100) and InSb (111) wafers. This technique is capable of improving the smoothness CMP surfaces and simultaneously producing a thin desorbable oxide layer for molecular beam epitaxial growth. By implementing recipes with specific gas mixtures, cluster energy sequences, and doses, an engineered oxide can be produced. Using GaSb wafers with a high quality CMP finish, we have demonstrated surface smoothing of GaSb by reducing the average roughness from 2.8Å to 1.7Å using a dual energy CF4/O2-GCIB process with a total charge fluence of 4×1015ions/cm2. For the first time, a GCIB grown oxide layer that is comprised of mostly gallium oxides which desorbed at 530°C in our molecular beam epitaxy system is reported, after which GaSb/AlGaSb epilayers have been successfully grown. Using InSb, we successfully demonstrated substrate smoothing by reducing the average roughness from 2.5Å to 1.6Å using a triple energy O2-GCIB process with a charge fluence 9×1015ions/cm2. In order to further demonstrate the ability of GCIB to smooth InSb surfaces, sharp ∼900nm high tips have been formed on a poorly mechanically polished InSb (111)A wafer and subsequently reduced to a height of ∼100nm, an improvement by a factor of eight, using a triple energy SF6/O2-GCIB process with a total charge fluence of 6×1016ions/cm3.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3970
Author(s):  
Wojciech J. Nowak

An electron backscattered diffraction (EBSD) method provides information about the crystallographic structure of materials. However, a surface subjected to analysis needs to be well-prepared. This usually requires following a time-consuming procedure of mechanical polishing. The alternative methods of surface preparation for EBSD are performed via electropolishing or focus ion beam (FIB). In the present study, plasma etching using a glow discharge optical emission spectrometer (GD-OES) was applied for surface preparation for EBSD analysis. The obtained results revealed that plasma etching through GD-OES can be successfully used for surface preparation for EBSD analysis. However, it was also found that the plasma etching is sensitive for the alloy microstructure, i.e., the presence of intermetallic phases and precipitates such as carbides possess a different sputtering rate, resulting in non-uniform plasma etching. Preparation of the cross-section of oxidized CM247 revealed a similar problem with non-uniformity of plasma etching. The carbides and oxide scale possess a lower sputtering rate than the metallic matrix, which caused formation of relief. Based on obtained results, possible resolutions to suppress the effect of different sputtering rates are proposed.


1995 ◽  
Vol 388 ◽  
Author(s):  
Yoshihisa Watanabe ◽  
Yoshikazu Nakamura ◽  
Shigekazu Hirayama ◽  
Yuusaku Naota

AbstractAluminum nitride (AlN) thin films have been synthesized by ion-beam assisted deposition method. Film deposition has been performed on the substrates of silicon single crystal, soda-lime glass and alumin A. the influence of the substrate roughness on the film roughness is studied. the substrate temperature has been kept at room temperature and 473K and the kinetic energy of the incident nitrogen ion beam and the deposition rate have been fixed to 0.5 keV and 0.07 nm/s, respectively. the microstructure of the synthesized films has been examined by X-ray diffraction (XRD) and the surface morphology has been observed by atomic force microscopy(AFM). IN the XRD patterns of films synthesized at both room temperature and 473K, the diffraction line indicating the alN (10*0) can be discerned and the broad peak composed of two lines indicating the a1N (00*2) and a1N (10*1) planes is also observed. aFM observations for 100 nm films reveal that (1) the surface of the films synthesized on the silicon single crystal and soda-lime glass substrates is uniform and smooth on the nanometer scale, (2) the average roughness of the films synthesized on the alumina substrate is similar to that of the substrate, suggesting the evaluation of the average roughness of the film itself is difficult in the case of the rough substrate, and (3) the average roughness increases with increasing the substrate temperature.


2015 ◽  
Vol 1087 ◽  
pp. 116-120 ◽  
Author(s):  
Te Chuan Lee ◽  
Maizlinda Izwana Idris ◽  
Hasan Zuhudi Abdullah ◽  
Charles Christopher Sorrell

Anodic oxidation is a surface modification method which combines electric field driven metal and oxygen ion diffusion for formation of oxide layer on the anode surface. Anodised titanium has been widely use in biomedical applications especially in dental implant. This study aimed to investigate the effect of electrolyte concentration on titanium. Specifically, the titanium foil was anodised in mixture of β-glycerophosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA) with different concentration (0.02 M + 0.2 M and 0.04 M + 0.4 M), anodising time (10 min), applied voltage (150, 200, 250, 300 and 350 V) and current density (10 mA.cm-2) at room temperature. Surface oxide properties of anodised titanium were characterised by using glancing angle X-ray diffraction (GAXRD), field emission scanning electron microscope (FESEM), focused ion beam (FIB) milling and digital camera. With increasing electrolyte concentration, the oxide layer became more porous. The GAXRD results also showed that rutile formed at high applied voltage (≥300 V) when the higher concentration of electrolyte was used.


2015 ◽  
Vol 22 (03) ◽  
pp. 1550035 ◽  
Author(s):  
WEI-YUAN YU ◽  
SEN-HUI LIU ◽  
XIN-YA LIU ◽  
JIA-LIN SHAO ◽  
MIN-PEN LIU

In this study, Sn - Ag - Ti ternary alloy has been used as the active solder to braze pure aluminum and graphite in atmospheric conditions using ultrasonic vibration as an aid. The authors studied the formation, composition and decomposition temperature of the surface oxides of the active solder under atmospheric conditions. In addition, the wettability of Sn -5 Ag -8 Ti active solder on the surface of pure aluminum and graphite has also been studied. The results showed that the major components presented in the surface oxides formed on the Sn -5 Ag -8 Ti active solder under ambient conditions are TiO , TiO 2, Ti 2 O 3, Ti 3 O 5 and SnO 2. Apart from AgO and Ag 2 O 2, which can be decomposed at the brazing temperature (773 K), other oxides will not be decomposed. The oxide layer comprises composite oxides and it forms a compact layer with a certain thickness to enclose the melted solder, which will prevent the liquid solder from wetting the base metals at the brazing temperature. After ultrasonic vibration, the oxide layer was destroyed and the liquid solder was able to wet and spread out around the base materials. Furthermore, better wettability of the active solder was observed on the surface of graphite and pure aluminum at the brazing temperature of 773–823 K using ultrasonic waves. The ultrasonic wave acts as the dominant driving factor which promotes the wetting and spreading of the liquid solder on the surface of graphite and aluminum to achieve a stable and reliable brazed joint.


2014 ◽  
Vol 887-888 ◽  
pp. 233-239 ◽  
Author(s):  
She Ming Jiang ◽  
Shi Jie Feng ◽  
Zhen Hua Li ◽  
Qi Fu Zhang

Focusing on improving the galvanizability of the third generation automotive steel, the effect of surface oxides morphologies on the galvanizability was studied. The results show that the surface oxide types of sample steels by XPS analysis after annealing in different conditions are the same, only MnO and Cr2O3 were detected and no complex oxides exist on the surface. Morphologies of surface oxides can greatly influence the galvanizability of the third generation automotive steel, nodule-like oxides surface can contribute to better wettability and inhibition layer than vitreous film-like oxides surface. Galvanizing panels of nodule-like oxides surface steels only show pinhole-sized bare spots, while panels galvanized from vitreous film-like oxide surface steels reveal larger areas of bare spots and uncoated areas. Inhibition layer observed in galvanizing panels of nodule-like oxides surface steels are compact but not homogeneous, some inhibition layer grains are fine, and others are coarse. While the inhibition layer grains of panels galvanized from vitreous film-like oxide surface steels have a non-compact morphology with some particularly fine equiaxed crystals which developed deficiently.


2021 ◽  
Author(s):  
Gyo Wun Kim ◽  
Won Jun Chang ◽  
Ji Eun Kang ◽  
Hee Ju Kim ◽  
Geun Young Yeom

Abstract Even though EUV lithography has the advantage of implenting a finer pattern compared to ArF immersion lithography due to the use of 13.5 nm instead of 193 nm as the wavelengh of the light source, due to the low energy of EUV light source, EUV resist has a thinner thickness than conventional ArF resist. EUV resist having such a thin thickness is more vulnerable to radiation damage received during the etching because of its low etch resistance and also tends to have a problem of low etch selectivity. In this study, the radiation damage to EUV resist during etching of hardmask materials such as Si3N4, SiO2, etc. using CF4 gas was compared between neutral beam etching (NBE) and ion beam etching (IBE). When NBE was used, after the etching of 20 nm thick EUV resist, the line edge roughness (LER) increase and the critical dimension (CD) change of EUV resist were reduced by ~ 1/3 and ~ 1/2, respectively, compared to those by IBE. Also, at that EUV etch depth, the RMS(root mean square) surface roughness value of EUV resist etched by NBE was ~2/3 compared to that by IBE on the average. It was also confirmed that the etching selectivity between SiO2, Si3N4, etc. and EUV resist was higher for NBE compared to IBE. The less damage to the EUV resist and the higher etch selectivity of materials such as Si3N4 and SiO2 over EUV resist for NBE compared to IBE are believed to be related to the no potential energy released by the neutralization of the ions during the etching for NBE.


2005 ◽  
Vol 20 (6) ◽  
pp. 1396-1403 ◽  
Author(s):  
C.Y. Tam ◽  
C.H. Shek

The oxidation kinetics of Cu60Zr30Ti10 bulk metallic glass and its crystalline counterpart were studied in oxygen environment over the temperature range of 573–773 K. The oxidation kinetics, measured with thermogravimetric analysis, of the metallic glass follows a linear rate law between 573 and 653 K and a parabolic rate law between 673 and 733 K. It was also found that the oxidation activation energy of metallic glass is lower than that of its crystalline counterpart. The x-ray diffraction pattern showed that the oxide layer is composed of Cu2O, CuO, ZrO2, and metallic Cu. Cu enrichment on the topmost oxide layer of the metallic glass oxidized at 573 K was revealed by x-ray photoelectron spectroscopy while there was a decrease in Cu content in the innermost oxide layer. The oxide surface morphologies observed from scanning electron microscopy showed that ZrO2 granules formed at low temperatures while whiskerlike copper oxides formed at higher temperatures.


1998 ◽  
Vol 13 (7) ◽  
pp. 1735-1737 ◽  
Author(s):  
Donald R. Gilbert ◽  
Dong-Gu Lee ◽  
Rajiv K. Singh

We have developed a unique method to produce smooth diamond films using a modified microwave plasma process system. This method consists of sequential in situ deposition and planarization in an electron cyclotron resonance plasma system. Diamond films were deposited to a thickness of 3.0 μm in this system at a pressure of 1.000 Torr from gas mixtures of methanol and hydrogen. Deposition was followed by planarization using a two-grid ion beam extraction process with a pure oxygen plasma at 10 mTorr. The average roughness of the diamond films so produced was as low as 30 nm, which was a factor of two lower than that of the as-deposited diamond films.


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