scholarly journals Extreme Sub-Wavelength Structure Formation from Mid-IR Femtosecond Laser Interaction with Silicon

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1192
Author(s):  
Kevin Werner ◽  
Enam Chowdhury
Keyword(s):  
Electron Microscopy ◽  
Femtosecond Laser ◽  
Structure Formation ◽  
Single Crystal Silicon ◽  
Pulse Number ◽  
Native Oxide ◽  
New Paradigm ◽  
Crystal Silicon ◽  
Cross Sectional ◽  
Sub Wavelength

Mid-infrared (MIR) wavelengths (2–10 μm) open up a new paradigm for femtosecond laser–solid interactions. On a fundamental level, compared to the ubiquitous near-IR (NIR) or visible (VIS) laser interactions, MIR photon energies render semiconductors to behave like high bandgap materials, while driving conduction band electrons harder due to the λ2 scaling of the ponderomotive energy. From an applications perspective, many VIS/NIR opaque materials are transparent for MIR. This allows sub-surface modifications for waveguide writing while simultaneously extending interactions to higher order processes. Here, we present the formation of an extreme sub-wavelength structure formation (∼λ/100) on a single crystal silicon surface by a 3600 nm MIR femtosecond laser with a pulse duration of 200 fs. The 50–100 nm linear structures were aligned parallel to the laser polarization direction with a quasi-periodicity of 700 nm. The dependence of the structure on the native oxide, laser pulse number, and polarization were studied. The properties of the structures were studied using scanning electron microscopy (SEM), atomic force microscopy (AFM), cross-sectional transmission electron-microscopy (CS-TEM), electron diffraction (ED), and energy-dispersive X-ray spectroscopy (EDX). As traditional models for the formation of laser induced periodic surface structure do not explain this structure formation, new theoretical efforts are needed.

Single Crystal Silicon Carbide On Silicon Using A Supersonic Gas Jet Of Methylsilane

1997 ◽  
Vol 483 ◽  
Author(s):  
S. A. Ustin ◽  
C. Long ◽  
L. Lauhon ◽  
W. Ho
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Single Crystal Silicon ◽  
Maximum Growth ◽  
X Ray Diffraction ◽  
Crystal Silicon ◽  
Cross Sectional ◽  
Supersonic Molecular Beam ◽  
Transmission Electron

AbstractCubic SiC films have been grown on Si(001) and Si(111) substrates at temperatures between 600 °C and 900 °C with a single supersonic molecular beam source. Methylsilane (H3SiCH3) was used as the sole precursor with hydrogen and nitrogen as seeding gases. Optical reflectance was used to monitor in situ growth rate and macroscopic roughness. The growth rate of SiC was found to depend strongly on substrate orientation, methylsilane kinetic energy, and growth temperature. Growth rates were 1.5 to 2 times greater on Si(111) than on Si(001). The maximum growth rates achieved were 0.63 μm/hr on Si(111) and 0.375μm/hr on Si(001). Transmission electron diffraction (TED) and x-ray diffraction (XRD) were used for structural characterization. In-plane azimuthal (ø-) scans show that films on Si(001) have the correct 4-fold symmetry and that films on Si(111) have a 6-fold symmetry. The 6-fold symmetry indicates that stacking has occurred in two different sequences and double positioning boundaries have been formed. The minimum rocking curve width for SiC on Si(001) and Si(111) is 1.2°. Fourier Transform Infrared (FTIR) absorption was performed to discern the chemical bonding. Cross Sectional Transmission Electron Microscopy (XTEM) was used to image the SiC/Si interface.

Electronic Properties of Femtosecond Laser Induced Modified Spots on Single Crystal Silicon Carbide

2010 ◽  
Vol 645-648 ◽  
pp. 239-242 ◽  
Author(s):  
Takuro Tomita ◽  
M. Iwami ◽  
M. Yamamoto ◽  
M. Deki ◽  
Shigeki Matsuo ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Femtosecond Laser ◽  
Single Crystal ◽  
Specific Resistance ◽  
Single Crystal Silicon ◽  
Metal Contacts ◽  
Crystal Silicon ◽  
Current Voltage ◽  
Fs Laser ◽  
Current Voltage Characteristics

Femtosecond (fs) laser modification on single crystal silicon carbide (SiC) was studied from the viewpoints of electric conductivity. Fourier transform infrared (FTIR) spectroscopy was carried out on femtosecond laser modified area. The intensity decrease of reststrahlen band due to the modification was observed, and this decrease was explained by the degradation of crystallinity due to the laser irradiation. Polarization dependence of reststrahlen band was also observed on laser modified samples. Current-voltage characteristics and Hall measurements on fs-laser modified region were carried out by fabricating the metal contacts on the ion implanted areas. The specific resistance up to 5.9×10-2 m was obtained for fs-laser modified area.

Heteroepitaxial Metal Oxides on Silicon by Laser Ablation

1990 ◽  
Vol 191 ◽  
Author(s):  
D. B. Fenner ◽  
D. K. Fork ◽  
G. A. N. Connell ◽  
J. B. Boyce ◽  
F. A. Ponce ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Single Crystal Silicon ◽  
Native Oxide ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Crystal Silicon ◽  
Ybco Films ◽  
Zero Resistance ◽  
High Degree

ABSTRACTThin epitaxial films of cubic - fluorite structured PrO2 and YSZ (yttria- stabilized zirconia) were grown on single crystal silicon substrates using the laser ablation - deposition technique. X-ray diffraction theta two - theta, omega rocking and phi scans indicate a high degree of epitaxial orientation of the films to the Si lattice. The highest quality of epitaxy was obtained with the PrO2 [111] oriented normal to Si(111) surfaces and the cubic YSZ [100] normal to Si(100) surfaces. For both PrO2 and YSZ, high epitaxial quality required the removal of the Si native oxide prior to deposition and careful control of the deposition environment. It was further found that the YSZ films on Si(100) were an excellent surface for subsequent laser ablation of YBCO films by the usual in situ process. The resistivity of this YBCO was ≈ 250 micro-ohm-cm at 300 K, extrapolated to the resistivity -temperature origin, showed a sharp transition to zero resistance at ≈ 85 K and was nearly identical to high quality YBCO films deposited on (bulk) YSZ substrates.

Diffusion of as and B in Polysilicon/ Single Crystal Silicon Systems

1990 ◽  
Vol 182 ◽  
Author(s):  
K. Park ◽  
S. Batra ◽  
S. Banerjee ◽  
G. Lux ◽  
R. Manukonda
Keyword(s):  
Single Crystal ◽  
Grain Boundaries ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Vapor ◽  
Doping Profile ◽  
Native Oxide ◽  
Crystal Silicon ◽  
Solid Solubility Limit ◽  
Cross Sectional ◽  
Polysilicon Layer

AbstractComparative studies of As and B diffusion in polysilicon-on-single-crystal Si systems have been performed by Cross-sectional Transmission Electron Microscopy (XTEM) and Secondary Ion Mass Spectrometry (SIMS). Arsenic and BF2 implanted in 300 nm Low Pressure Chemical Vapor Deposition (LPCVD) polysilicon are diffused into the underlying Si substrate by Rapid Thermal Annealing (RTA) or furnace annealing. Diffusion profiles of Asappear to be continuous across the poly/single crystal Si interface except for a peak at the interface and show a gradual increase towards the interface within the polysilicon layer due to an inhomogeneous distribution of grain sizes in Asimplanted polysilicon layers. On the other hand, indiffusion of B gives a discontinuous doping profile at the interface due to accumulation of B-defect complexes created by dissolution of defectclusters in polysilicon. At low anneal temperatures, the B profiles in single crystal Siare shallower than the As profiles. This is because most of the B in polysilicon films is immobile during annealing near the peak region where the solid solubility limit is exceeded, and because of low B segregation at grain boundaries, thereby reducing the impactof grain boundaries in terms of high diffusivity. At high anneal temperatures, the native oxide at the interface breaks up and causes the polysilicon layer to align epitaxiallywith respect to the underlying substrate. Time to breakup of interfacial oxide depends on dopant species and anneal temperatures. Oxide breakup takes longer for As-doped samples than for B-doped samples. For high thermal budget anneals, B diffusion into the substrate is greater than As diffusion because of higher B diffusivities in single crystal Si.

Failure of micron scale Single Crystal Silicon bars due to torsion developed by MEMS micro instruments

1998 ◽  
Vol 518 ◽  
Author(s):  
Taher Saif ◽  
N. C. MacDonald
Keyword(s):  
Single Crystal ◽  
Single Crystal Silicon ◽  
Theory Of Elasticity ◽  
Shear Stresses ◽  
Electrostatic Actuator ◽  
Crystal Silicon ◽  
Cross Sectional ◽  
Lever Arm ◽  
Spring Constants

AbstractWe present an experimental study on a single crystal silicon (SCS) bar subjected to pure torsion using MEMS micro instruments. The bar is in the form of a pillar, anchored at one end to the silicon substrate. It is attached to a lever arm at the other end. The pillar has a minimum cross sectional area at its mid height. The cross section coincides with the (100) plane of SCS. Torsion is generated by applying two equal forces on the lever arm on either side of the pillar. Two micro instruments apply the forces. Each consists of an electrostatic actuator and a component that calibrates it. The actuator generates high force (≈ 200 µN at 50 V) and is capable of developing large displacements (≈ 10 μm). Calibration involves determination of the force generated by the actuator at an applied voltage, as well as the linear and higher order spring constants of its springs. Each microinstrument is thus calibrated independently.With the application of forces by the two micro instruments, a torque is generated which twists the pillar. The angle of twist at different applied voltages are recorded using an angular scale. The corresponding torques are determined from the calibration parameters of the actuators. Torque is applied until the pillar fractures. Two such sample pillars, samples 1 and 2, are tested. There cross sectional areas are 1 and 2.25 µm2. We find that both the pillars behave linearly until failure. The stresses prior to fracture are evaluated based on anisotropic theory of elasticity. Samples 1 and 2 fail at shear stresses of 5.6 and 2.6 GPa respectively. The fracture surfaces seem to coincide with the (111) plane of SCS.

A study of 2 MeV oxygen implantation to form deeply buried SiO2 layers

1989 ◽  
Vol 4 (5) ◽  
pp. 1227-1232 ◽  
Author(s):  
J. J. Grob ◽  
A. Grob ◽  
P. Thevenin ◽  
P. Siffert ◽  
C. d'Anterroches ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystal Silicon ◽  
Single Step ◽  
Annealing Process ◽  
Dislocation Network ◽  
Crystal Silicon ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Distribution Moments ◽  
Best Fit

Oxygen ions were implanted into (100) oriented single crystal Si at energies in the range of 0.6 to 2 MeV at normal and oblique (60°) incidences. Oxygen concentration profiles were measured using the 16O(d, α)14N nuclear reaction for 900 keV deuterons. The experimentally measured oxygen distributions were subsequently fitted to the theoretical profiles calculated assuming the Pearson VI distribution. The distribution moments (Rp, ΔRp, ΔR⊥ skewness, and kurtosis) were deduced as the best fit parameters and compared to the computer simulation results (TRIM 87 and PRAL). Whatever the calculation method, the measured Rp and ΔRp values are close to those predicted by the theory. Deeply buried SiO2 layers were formed using a single step implantation and annealing process. A dose of 1.8 × 1018/cm2 of 2 MeV O+ was implanted into the Si substrate maintained at a temperature of 550 °C. The implanted samples were characterized using the Rutherford backscattering (RBS)/channeling technique and cross-sectional transmission electron microscopy (XTEM). The implanted samples were subsequently annealed at 1350 °C for 4 h in an Ar ambient. The annealing process results in creating a continuous SiO2 layer, 0.4 μm thick below a 1.6 μm thick top single crystal silicon overlayer. The buried SiO2 layer contains the well-known faceted Si inclusions. The density of dislocations within the top Si layer remains lower than the XTEM detection limit of 107/cm2. Between the Si overlayer and the buried SiO2 a layer of faceted longitudinal SiO2 precipitates is present. A localized dislocation network links the precipitates to the buried SiO2 layer.

Electron Microscopy and the Electronics Industry: Partners in Development

1990 ◽  
Vol 48 (1) ◽  
pp. 12-13
Author(s):  
W. F. Brinkman
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Single Crystal ◽  
Single Crystal Silicon ◽  
Microscopic Analysis ◽  
Crystal Form ◽  
Electronics Industry ◽  
Crystal Silicon ◽  
Free Material ◽  
The Relationship

Since the invention of the transistor and the birth of the solid-state electronics industry, electron microscopy has been an integral part of the boom in the science and technology of semiconductors. The relationship has been symbiotic: the technique of microscopy has probably gained almost as much as the electronics industry from innovations. Historically, semiconductor research has always come down to a question of the growth of perfect materials with perfect interfaces, and microscopic analysis below the optical level has been essential to improvements. When applications for the semiconductors germanium and silicon were discovered in solid-state devices, its became necessary to grow high-quality single crystals free of defects. A lot of work at Bell Labs and other institutions was directed at understanding the behavior of dislocations in crystals. Bill Schockley, a co-inventor of the transistor, is well-known for his contributions to dislocation theory, particularly dislocation dissociation in semiconductors. Bob Heidenreich, from Bell Labs, contributed much to the early stages of microscopy of defects and dislocations. The need for dislocation-free material generated extensive efforts around the world which led to the growth of high-purity single-crystal silicon in the 1960’s. Silicon is now the highest quality and purest material available, and also the cheapest in single-crystal form.

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