Solid-phase epitaxy of ion-implanted LiNbO3 for optical waveguide fabrication

1987 ◽  
Vol 2 (2) ◽  
pp. 222-230 ◽  
Author(s):  
Ch. Buchal ◽  
P. R. Ashley ◽  
B. R. Appleton
Keyword(s):  
Optical Waveguides ◽  
Solid Phase ◽  
Surface Region ◽  
Liquid Nitrogen Temperature ◽  
High Concentration ◽  
Near Surface ◽  
Crystalline Substrate ◽  
A New Technique ◽  
Waveguide Fabrication ◽  
Water Saturated

A new technique for successfully fabricating high-quality optical waveguides in LiNbO3 is reported. A high concentration of Ti is implanted with the substrate at liquid nitrogen temperature and an amorphous, Ti-rich, nonequilibrium phase is produced in the implanted, near-surface region. Subsequent thermal annealing in water-saturated oxygen atmosphere at up to 1000°C initiates solid-phase epitaxial regrowth onto the crystalline substrate. A highquality single crystalline layer results that is rich in Ti and has excellent waveguiding properties.

Solid-Phase Epitaxy of Ti-Implanted LiNbO3

1987 ◽  
Vol 93 ◽  
Author(s):  
D. B. Poker
Keyword(s):  
Activation Energy ◽  
Optical Waveguides ◽  
Solid Phase ◽  
Complete Removal ◽  
Liquid Nitrogen Temperature ◽  
Index Of Refraction ◽  
Optical Index ◽  
Epitaxial Regrowth ◽  
Residual Damage ◽  
Water Saturated

ABSTRACTThe implantation of Ti into LiNbO3 has been studied as a means of altering the optical index of refraction to produce optical waveguides. Implanting 2 × 1017 atoms/cm2 of 360-keV Ti at liquid nitrogen temperature produces a highly damaged region extending to a depth of about 4000 Å. Solid-phase epitaxial regrowth of the LiNbO3 can be achieved by annealing in a water-saturated oxygen atmosphere at 400°C, though complete removal of the residual damage usually requires temperatures in excess of 800°C. The solid-phase epitaxial regrowth rate exhibits an activation energy of 2 eV at doses below 3 × 1016 Ti/cm2, but both the regrowth rate and activation energy decrease at higher doses. At doses above 1 × 1017 Ti/cm2, the solid-phase epitaxial regrowth occurs only at temperatures above 800°C.

Solid-phase epitaxy of Ti-implanted LiNbO3

1989 ◽  
Vol 4 (2) ◽  
pp. 412-416 ◽  
Author(s):  
D. B. Poker ◽  
D. K. Thomas
Keyword(s):  
Optical Waveguides ◽  
Solid Phase ◽  
Complete Removal ◽  
Amorphous Region ◽  
Liquid Nitrogen Temperature ◽  
High Dose ◽  
Solid Phase Epitaxy ◽  
Complete Recrystallization ◽  
Water Saturated ◽  
Saturated Oxygen

The solid-phase epitaxy of LiNbO3 following ion implantation of Ti dopant for the purpose of producing optical waveguides has been studied. Implanting 360-keV Ti at liquid nitrogen temperature produces a highly damaged region extending to a depth of about 400 nm. This essentially amorphous region can be recrystallized epitaxially by annealing in a water-saturated oxygen atmosphere at temperatures near 400 °C. though complete removal of all irradiation-induced damage requires temperatures in excess of 600 °C. The activation energy of the regrowth is 2.0 eV for implanted fluences below 3 ⊠ 1016 Ti/cm2. At higher fluences the regrowth proceeds more slowly, and Ti dopant segregates at the regrowth interface. Complete recrystallization following high-dose implantation requires annealing temperatures in excess of 800 °C.

Ion Implantation of Ti INTO LiNbO3: Fabrication of Waveguides and Simple Modulators

1989 ◽  
Vol 152 ◽  
Author(s):  
C. W. White ◽  
D. K. Thomas ◽  
P. R. Ashley ◽  
W. S. C. Chang ◽  
C. Buchal
Keyword(s):  
Ion Implantation ◽  
Solid Phase ◽  
Surface Region ◽  
Amorphous Region ◽  
Index Of Refraction ◽  
Near Surface ◽  
Channel Waveguides ◽  
High Doses ◽  
Water Saturated ◽  
Saturated Oxygen

ABSTRACTIon implantation has been used to introduce Ti at very high doses (>3 × 1017 /cm2) into the near-surface region of LiNbO3 to change the index of refraction.’ In the as-implanted state, the near surface is amorphous. Thermal annealing in water-saturated oxygen 1000°C crystallizes the amorphous region and incorporates the Ti into substitutional sites in the lattice at concentrations that exceed 10 at.%. Recrystallization takes place by solid-phase epitaxy. Both planar and channel waveguides have been fabricated with optical attenuations of <1 dB/cm. Both Mach-Zehnder and Bragg modulators have been fabricated using Ti implantation of LiNbO3. The characteristics of these devices have been determined and will be reported. The higher Ti concentrations which can be achieved by implantation allows tighter mode confinement and smaller mode profiles than with Ti-diffused guides.

THE SURFACE STRUCTURE OF A LOW Pd Cu/Pd-(110) CRYSTAL ALLOY

1994 ◽  
Vol 01 (04) ◽  
pp. 569-571 ◽  
Author(s):  
M. BOWKER ◽  
M. NEWTON ◽  
S.M. FRANCIS ◽  
M. GLEESON ◽  
C. BARNES
Keyword(s):  
Surface Structure ◽  
Surface Region ◽  
Single Scattering ◽  
Alloy Surface ◽  
High Concentration ◽  
Near Surface ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
Layer 2

X-ray photoelectron diffraction studies of this alloy surface have been carried out and indicate that there is a significant expansion of the lattice in the near-surface region due to the high concentration of Pd in layer 2. Preliminary single scattering calculations lend support to this proposal for the surface structure, and place this expansion in the subsurface mainly between layers 2 and 3.

Influence of the Temperature of Implantation on the Morphology of Defects in MeV Implanted GaAs.

1989 ◽  
Vol 147 ◽  
Author(s):  
G. Braunstein ◽  
Samuel Chen ◽  
S.-Tong Lee ◽  
G. Rajeswaran.
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Point Defects ◽  
Room Temperature ◽  
Surface Region ◽  
Amorphous Region ◽  
Liquid Nitrogen Temperature ◽  
Dislocation Loops ◽  
Near Surface ◽  
Epitaxial Regrowth

AbstractWe have studied the influence of the temperature of implantation on the morphology of the defects created during 1-MeV implantation of Si into GaAs, using RBS-channeling and TEM. The annealing behavior of the disorder has also been investigated.Implantation at liquid-nitrogen temperature results in the amorphization of the implanted sample for doses of 2×1014 cm−2 and larger. Subsequent rapid thermal annealing at 900°C for 10 seconds leads to partial epitaxial regrowth of the amorphous layer. Depending on the implantation dose, the regrowth can proceed from both the front and back ends of the amorphous region or only from the deep end of the implanted zone. Nucleation and growth of a polycrystalline phase occurs concurrently, limiting the extent of the epitaxial regrowth. After implantation at room temperature and above, two distinct types of residual defects are observed or inferred: point defect complexes and dislocation loops. Most of the point defects disappear after rapid thermal annealing at temperatures ≥ 700°C. The effect of annealing on the dislocation loops depends on the distance from the surface of the sample. Those in the near surface region disappear upon rapid thermal annealing at 700°C, whereas the loops located deeper in the sample grow in size and begin to anneal out only at temperatures in excess of 900°C. Implantation at temperatures of 200 - 300°C results in a large reduction in the number of residual point defects. Subsequent annealing at 900°C leads to a nearly defect-free surface region and, underneath that, a buried band of partial dislocation loops similar to those observed in the samples implanted at room temperature and subsequently annealed.

Optical Waveguide Fabrication by Stoichiometric Implantation of Ti and O into LiNbO3

1989 ◽  
Vol 157 ◽  
Author(s):  
D. B. Pokers ◽  
W. Xia
Keyword(s):  
Phase Separation ◽  
Optical Waveguides ◽  
Room Temperature ◽  
High Substrate Temperature ◽  
The Stability ◽  
Waveguide Fabrication ◽  
Water Saturated ◽  
Substrate Annealing ◽  
Planar Optical Waveguides ◽  
Saturated Oxygen

ABSTRACTX-cut substrates of LiNbO3 have been implanted at 500°C with Ti and O to doses of 2.5 and 7.5×l017 ions/cm2, respectively. The high substrate temperature during implantation ensures dynamic recrystallization, preserving the crystallinity of the LiNbOs-The stability of the stoichiometric implants is enhanced sufficiently that annealing at 1000°C proceeds with no surface degradation of the substrate. Annealing under identical conditions without the 0 implant usually results in phase separation of an oxide at the surface, even when annealing is performed immediately following implantation. Samples implanted with Ti and O to preserve the stoichiometric metahoxygen ratio of the substrate can be stored at room temperature for several months without phase separation. Planar optical waveguides have been produced by stoichiometric implantation followed by annealing in water-saturated oxygen for one hour at temperatures of 900 and 1000°C. The sample annealed at 900°C supported a single lossy mode, while the 1000°C sample supported two propagating modes and one lossy mode at λ=0.6μm.

Laser-Induced Doping of CdTe Crystals in Different Environments

2011 ◽  
Vol 222 ◽  
pp. 32-35 ◽  
Author(s):  
Volodymyr A. Gnatyuk ◽  
Sergiy N. Levytskyi ◽  
Oleksandr I. Vlasenko ◽  
Toru Aoki
Keyword(s):  
Solid Phase ◽  
Laser Action ◽  
Surface Region ◽  
Laser Pulses ◽  
High Energy ◽  
Nanosecond Laser ◽  
High Concentration ◽  
Low Leakage ◽  
Low Leakage Current ◽  
Fabrication Procedure

Different procedures of laser-induced doping of the surface region of semi-insulating CdTe semiconductor are discussed. CdTe crystals pre-coated with an In dopant film were subjected to irradiation with nanosecond laser pulses in different environments (vacuum, gas or water). The dopant self-compensation phenomenon was overcome under laser action and In impurity with high concentration was introduced in a thin surface layer of CdTe. In the case of a thick (300-400 nm) In dopant film, laser-induced shock wave action has been considered as the mechanism of solid-phase doping. Formed In/CdTe/Au diode structures showed high rectification depending on the fabrication procedure. Diodes with low leakage current were sensitive to high energy radiation.

In Situ Tem Studies of The Growth of Strained Si1-xGex By Solid Phase Epitaxy

1990 ◽  
Vol 202 ◽  
Author(s):  
D. C. Paine ◽  
D. J. Howard ◽  
N. D. Evans ◽  
D. W. Greve ◽  
M. Racanelli ◽  
...  
Keyword(s):  
Activation Energy ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Surface Region ◽  
In Situ Tem ◽  
Solid Phase Epitaxy ◽  
Near Surface ◽  
Strained Layer ◽  
Epitaxial Regrowth

ABSTRACTIn this paper we report on the epitaxial growth of strained thin film Si1-xGex on Si by solid phase epitaxy. For these solid phase epitaxy experiments, a 180-nm-thick strained-layer of Si1-xGex with xGe=11.6 at. % was epitaxially grown on <001> Si using chemical vapor deposition. The near surface region of the substrate, including the entire Si1-xGex film, was then amorphized to a depth of 380 nm using a two step process of 100 keV, followed by 200 keV, 29Si ion implantation. The epitaxial regrowth of the alloy was studied with in situ TEM heating techniques which enabled an evaluation of the activation energy for strained solid phase epitaxial regrowth. We report that the activation energy for Si1-xGex (x=l 1.6 at. %) strained-layer regrowth is 3.2 eV while that for unstrained regrowth of pure Si is 2.68 eV and that regrowth in the alloy is slower than in pure Si over the temperature range 490 to 600°C.

Anisotropic Dry Etching of S1O2 on Si and its Impact on Surface and Near-Surface Properties of the Substrate.

1986 ◽  
Vol 68 ◽  
Author(s):  
G. S. Oehrlein ◽  
G. J. Coyle ◽  
J. C. Tsang ◽  
R. M. Tromp ◽  
J. G. Clabes ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Surface Properties ◽  
Surface Region ◽  
Dry Etching ◽  
High Concentration ◽  
Photoelectron Emission ◽  
Plasma Exposure ◽  
Near Surface ◽  
Ion Channeling ◽  
Fluorocarbon Film

AbstractIn the present paper structural and chemical changes which can occur in the surface and near-surface properties of the substrate during anisotropic dry etching of SiO2 on Si will be reviewed.Silicon specimens which had been etched in CF4/X%H2 (X≤40) have been characterized by X-ray photoelectron emission spectroscopy, He ion channeling, H profiling and Raman scattering techniques.Key results of our studies are summarized as follows: Plasma exposure of a Si surface leads to the deposition of a thin (≤50Å thick) C,F-film.A Si-carbide containing Si region is formed during RIE which is localized near the fluorocarbon-film/Si interface.The near-surface region (∼30–50Å) of the Si substrate is also heavily disordered as found by ion channeling and Raman scattering.A modified, less damaged Si region has been found in the case of hydrogen-based etching gases, which extends from about 30–50Å from the surface to a depth in extent of 250Å and contains a high concentration (∼ 5 at.%) of H as shown by hydrogen profiling techniques.From the observation of Si-H and Si-H2 vibrational modes by Raman scattering it has been shown that some of the H is bonded to the Si lattice.

Gettering of Cu at Buried Damage Layers Made by Si Self Implantation

1989 ◽  
Vol 157 ◽  
Author(s):  
J.R. Liefting ◽  
R.J. Schreutelkamp ◽  
W.X. Lu ◽  
F.W. Saris
Keyword(s):  
Surface Layer ◽  
Thermal Annealing ◽  
Rutherford Backscattering Spectrometry ◽  
Surface Region ◽  
Amorphous Layer ◽  
High Concentration ◽  
Near Surface ◽  
Before And After ◽  
Dose Ranging ◽  
P Type

ABSTRACTChanneled implants have been performed with lOOkeV 28Si+ into p-type Si(100) to obtain a buried amorphous layer. Before and after recrystallization of the a-Si layer, Cu was implanted at an energy of 15 keV and a dose ranging from 5E13 to 1E15 I cm2- to obtain a high concentration of Cu in the near surface region. Also, Cu implants were performed into virgin Si for comparison. After Cu implantation, thermal annealing was performed at temperatures between 490 °C and 900 °C for 10 min. to 320 min. Cu profiles before and after annealing were studied with Rutherford Backscattering Spectrometry and channeling analysis. For the case where Cu was implanted after recrystallization of the buried amorphous layer, Cu was gettered at the position where the ale interfaces met during recrystallization. For the case where Cu was implanted before recrystallization, Cu diffused towards the buried a-Si region upon annealing and was trapped inside the recrystallizing buried amorphous layer. The results show that buried damage layers can effectively getter Cufrom the Si surface layer and gettering is most efficient at 600 °C.

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