ArF Excimer Laser-Induced Epitaxial Growth of GaAs Films on Si

1988 ◽  
Vol 116 ◽  
Author(s):  
Shirley S. Chu ◽  
T. L. Cpu ◽  
C. L. Chang
Keyword(s):  
Gallium Arsenide ◽  
Substrate Temperature ◽  
Excimer Laser ◽  
Substrate Surface ◽  
Molar Ratio ◽  
Structural Perfection ◽  
Lower Growth ◽  
Si Substrates ◽  
Gaas Films ◽  
Arf Excimer Laser

AbstractEpitaxial gallium arsenide films have been deposited on single crystalline GaAs substrates of {100} orientation and Si substrates of 3° off the {100} orientation by ArF excimer laser-induced metalorganic chemical vapor deposition. The important process parameters include the cleanliness of the substrate surface, substrate temperature, the composition, flow rate, and pressure of the reaction mixture, and the pulse energy and pulse rate of the laser. Particular attention was directed to the in-situ cleaning of the substrate surface prior to the deposition process. Homoepitaxial gallium arsenide films of good structural perfection have been deposited at 425°- 500 ° C and their single crystallinity has been confirmed by transmission electron microscopy. The carrier concentration decreases with increasing AsH3/(CH3)3 Ga molar ratio and with decreasing substrate temperature. Lower growth rate during the initial stage of deposition is necessary to obtain heteroepitaxial gallium arsenide films on Si with good structural perfection. The TEM examination of GaAs films of 0.15–0.2 µm thickness deposited on Si substrates at 500 °C has shown that stacking faults were present in the GaAs films; however, there is no apparent threading dislocations in the surface region of the thin GaAs film.

Observation of GaAs/Si Epitaxial Interfaces by Atomic Resolution Electron Microscopy

1986 ◽  
Vol 67 ◽  
Author(s):  
N. Otsuka ◽  
C. Choi ◽  
Y. Nakamura ◽  
S. Nagakura ◽  
R. Fischer ◽  
...  
Keyword(s):  
Substrate Surface ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Si Substrates ◽  
Voltage Electron ◽  
Resolution Electron ◽  
Gaas Films ◽  
Substrate Surfaces

ABSTRACTRecent studies have shown that high quality GaAs films can be grown by MBE on Si substrates whose surfaces are slightly tilted from the (100) plane. In order to investigate the effect of the tilting of substrate surfaces on the formation of threading dislocations, the GaAs/Si epitaxial interfaces have been observed with a 1 MB ultra-high vacuum, high voltage electron microscope. Two types of misfit dislocations, one with Burgers vectors parallel to the interface and the other with Burgers vectors inclined from the interface, were found in these epitaxial interfaces. The observation of crosssectional samples perpendicular to each other has shown that the tilting of the substrate surface directly influences the generation of these two types of misfit dislocations. The mechanism of the reduction of threading dislocations by the tilting of the substrate surface is discussed based on these observations.

High Selective Etching of SiO2/Si by ArF Excimer Laser

1993 ◽  
Vol 334 ◽  
Author(s):  
K. Kitamura ◽  
M. Murahara
Keyword(s):  
Laser Beam ◽  
Excimer Laser ◽  
Wavelength Region ◽  
Chemical Behavior ◽  
Mixed Gas ◽  
Reaction Cell ◽  
Si Substrates ◽  
Excimer Laser Irradiation ◽  
Arf Excimer Laser ◽  
Uv Absorption Spectrum

AbstractDry etching of SiO2 insulation layer has been required in the Si semiconductor manufacturing process. The etching of SiO2/Si is chemically carried out by using HF solution. We successfully demonstrated a new method for exclusive etching of SiO2 using the nitrosyle fluoride (NFO) gas which was produced from the mixed gas of NF3 and O2 with an ArF excimer laser irradiation.SiO2 and Si substrates were placed side by side in a reaction cell which was filled with 3% O2 gas in NF3 at the gas pressure of 380 Torr. ArF excimer laser beam was irradiated parallel to the substrates. The laser fluence was kept at lOOmJ/cm2. As soon as the mixed gas of NF3 and O2 was irradiated with the ArF laser beam, an intermediate product of NFO was produced. The chemical behavior of NFO was confirmed from the UV absorption spectrum with absorption in the 310 to 330nm wavelength region. In the presence of SiO2, the absorption of NFO diminished. The absorption of NO2, instead of NFO, appeared at 350nm. This indicates that the oxygen atoms of SiO2 were pulled out by NFO.The etching reactions continued for 3 minutes after irradiation when the SiO2 and Si substrates were kept in an atmosphere of the reactant gases. As a result, not the Si but SiO2 substrate was etched with the depth of 2000Å.

Photochemical Moisture Proof Coating on Nonlinear Optical Crystal by ArF Excimer Laser

2004 ◽  
Vol 843 ◽  
Author(s):  
M. Kojima ◽  
M. Murahara
Keyword(s):  
Excimer Laser ◽  
Nonlinear Optical ◽  
Silicone Oil ◽  
Crystal Surface ◽  
Substrate Surface ◽  
New Technology ◽  
Nonlinear Optical Crystal ◽  
Nonlinear Optical Crystals ◽  
Arf Excimer Laser ◽  
Optical Crystal

ABSTRACTSilicone oil was photo-chemically oxidized to change into SiO2 on the crystal by using an ArF excimer laser; the protective moistureproof film has been developed for a nonlinear optical crystal that is deliquescent.The nonlinear optical crystals such as CsLiB6O10 (CLBO) and KH2PO4 (KDP) are deliquescent, which causes their surfaces to be cloudy by absorbing moisture in the air. We, therefore, demonstrated the growth of the SiO 2 film directly on the crystal so as to be moistureproof.Firstly, dimethylsiloxane silicone oil (-O-Si(CH3)2-O-)n was poured on the substrate and coated by a spinner for making the silicone oil thin layer. Then, the ArF excimer laser was vertically irradiated on the sample in oxygen atmosphere. The O atom on the substrate surface was photo-excited by the laser to generate a high active O atom. At the same time, the Si-CH3 bond of the silicone oil was photo-dissociated and the dangling bond of Si was linked with the active O atom to form a SiO 2 film on the crystal surface.In short, the film formed by the new technology can be used as a protective coating, which has the moisture resistance and the UV permeability, for a nonlinear optical crystal.

Modeling of Silicon Deposition Yield at Low Temperature by ArF Excimer Laser Photolysis of Disilane

1992 ◽  
Vol 263 ◽  
Author(s):  
B. Fowler ◽  
S. Lian ◽  
S. Krishnan ◽  
C. Li ◽  
L. Jung ◽  
...  
Keyword(s):  
Gas Phase ◽  
Excimer Laser ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Film Deposition ◽  
Growth Surface ◽  
Phase Reaction ◽  
Gas Phase Reactions ◽  
Arf Excimer Laser ◽  
193 Nm

ABSTRACTNon-thermal Chemical Vapor Deposition (CVD) such as laser-enhanced photo-CVD of Si at low temperatures is important for Si-based heterostructures and doping superlattices. Growth kinetic models must be developed to allow these processes to be fully exploited. Intrinsic Si epitaxial layers were deposited at low substrate temperatures of 250-350ºC using the 193 nm output of an ArF excimer laser to directly dissociate Si2H6. The intrinsic film deposition rate can be described by a kinetic model that considers the gas phase reactions of the primary photolysis products and diffusion ofsilicon-bearing molecules to the growth surface. With the laser beam tangential to the substrate surface, growth rates as a function of beam-to-substrate distance have been characterized and indicate that very little gas phase reaction occurs for the dominant Si growth precursor. In order for intrinsic film deposition to result solely from Si2H6 photolysis products, a sticking coefficient ≥ 0.6 must be assigned to the dominant growth precursor in order to fit the observed yield of Si deposited in the films, indicating that the dominant growth precursor in 193 nm Si2H6 photolysis is perhaps H2SiSiH2.

Laser Induced Photochemical Vapor Deposition of Tungsten on Silicon

1989 ◽  
Vol 168 ◽  
Author(s):  
A. J. P. van Maaren ◽  
W. C. Sinke
Keyword(s):  
Laser Pulse ◽  
Substrate Temperature ◽  
Laser Irradiation ◽  
Excimer Laser ◽  
Vapor Deposition ◽  
Pulse Frequency ◽  
Arf Excimer Laser ◽  
193 Nm ◽  
Photochemical Vapor Deposition

AbstractAn ArF excimer laser (193 nm) aligned parallel to the substrate has been used to initiate photo-activation of the W-CVD process. W was deposited on silicon and SIMOX at a 310 °C substrate temperature using WF6 as a W precursor, together with H2. The samples were analyzed after deposition with SEM and 2 MeV He+ RBS, to obtain information about the reaction between WF6 and Si in laser-induced CVD of W. The data indicate that the reaction between WF6 and Si is suppressed upon laser irradiation. The suppression increases with increasing laser-pulse frequency. An explanation for this phenomenon is given in terms of atomic Hformation after (partial) photodissociation of WF6.

High Resolution Displacement of Functional Groups onto Fluorocarbon Resin Surface by Using ArF Excimer Laser

1996 ◽  
Vol 451 ◽  
Author(s):  
T. Shimizu ◽  
M. Murahara
Keyword(s):  
Contact Angle ◽  
High Resolution ◽  
Laser Beam ◽  
Thin Layer ◽  
Functional Groups ◽  
Excimer Laser ◽  
Laser Fluence ◽  
Large Area ◽  
Three Solutions ◽  
Arf Excimer Laser

ABSTRACTA Fluorocarbon resin surface was selectively modified by irradiation with a ArF laser beam through a thin layer of NaAlO2, B(OH)3, or H2O solution to give a hydrophilic property. As a result, with low fluence, the surface was most effectively modified with the NaAlO2 solution among the three solutions. However, the contact angle in this case changed by 10 degrees as the fluence changed only 1mJ/cm2. When modifying a large area of the surface, high resolution displacement could not be achieved because the laser beam was not uniform in displacing functional groups. Thus, the laser fluence was successfully made uniform by homogenizing the laser beam; the functional groups were replaced on the fluorocarbon resin surface with high resolution, which was successfully modified to be hydrophilic by distributing the laser fluence uniformly.

In Situ Diagnostics of Vuv Laser Cvd of Semiconductor Interfaces by Ftir Spectroscopy and Spectroscopic Ellipsometry

1995 ◽  
Vol 397 ◽  
Author(s):  
M. Barth ◽  
J. Knobloch ◽  
P. Hess
Keyword(s):  
Film Thickness ◽  
Bulk Material ◽  
Substrate Surface ◽  
Cluster Formation ◽  
Interface Layer ◽  
Native Oxide ◽  
Initial Growth ◽  
Difference Spectra ◽  
Si Substrates

ABSTRACTThe growth of high quality amorphous hydrogenated semiconductor films was explored with different in situ spectroscopic methods. Nucleation of ArF laser-induced CVD of a-Ge:H on different substrates was investigated by real time ellipsometry, whereas the F2 laser (157nm) deposition of a-Si:H was monitored by FTIR transmission spectroscopy. The ellipsometric studies reveal a significant influence of the substrate surface on the nucleation stage, which in fact determines the electronic and mechanical properties of the bulk material. Coalescence of initial clusters occurs at a thickness of 16 Å for atomically smooth hydrogen-terminated c-Si substrates, whereas on native oxide covered c-Si substrates the bulk volume void fractions are not reached until 35 Å film thickness. For the first time we present a series of IR transmission spectra with monolayer resolution of the initial growth of a-Si:H. Hereby the film thickness was measured simultaneously using a quartz crystal microbalance with corresponding sensitivity. The results give evidence for cluster formation with a coalescence radius of about 20 Å. Difference spectra calculated for layers at different depths with definite thickness reveal that the hydrogen-rich interface layer stays at the substrate surface and does not move with the surface of the growing film. The decrease of the Urbach energy switching from native oxide to H-terminated substrates suggests a strong influence of the interface morphology on the bulk material quality.

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