Pulsed Ruby Laser Annealing of Zn, Mg, Se and Si Ion Implants in Semiconducting Gaas

1980 ◽  
Vol 1 ◽  
Author(s):  
Douglas H. Lowndes ◽  
J. W. Cleland ◽  
W. H. Christie ◽  
R. E. Eby
Keyword(s):  
Ruby Laser ◽  
Laser Annealing ◽  
Laser Energy ◽  
Impurity Scattering ◽  
Surface Region ◽  
High Dose ◽  
Near Surface ◽  
Scattering Centers ◽  
High Concentrations ◽  
P Type

ABSTRACTThe properties of p+ and n+ layers formed by pulsed ruby laser annealing (PRLA) of shallow (Rp ~ 320–680 Å) implantations of Mg, Zn, Si and Se ions in both n- and p-type semiconducting GaAs have been evaluated using a combination of SIMS and electrical properties measurements. High activation (> 80%) was obtained for high dose (5 × 1015 ions/cm2 ) implants of both Mg and Zn, within a pulsed laser energy density “window” 0.5 ≤ Eλ ≤ 0.8 J/cm2 (FWHM pulse duration = 20–25 ns). SIMS measurements following PRLA show a wellbehaved increasing penetration of dopant ions into the GaAs substrate, with dopant ion concentrations well in excess of 1020 ions/cm3 in the near-surface region. Measured hole mobilities are consistent with the values anticipated for these high concentrations of ionized impurity scattering centers.

Photoluminescence of Pulsed Ruby Laser Annealed Crystalline and Ion Implanted GaAs

1981 ◽  
Vol 4 ◽  
Author(s):  
Douglas H. Lowndes ◽  
Bernard J. Feldman
Keyword(s):  
Radiative Recombination ◽  
Laser Annealing ◽  
Laser Energy ◽  
Pulsed Laser ◽  
High Dose ◽  
Pulsed Laser Annealing ◽  
Recombination Centers ◽  
Pl Intensity ◽  
P Type ◽  
Ion Implanted

ABSTRACTIn an effort to understand the origin of defects earlier found to be present in p–n junctions formed by pulsed laser annealing (PLA) of ion implanted (II) semiconducting GaAs, photoluminescence (PL) studies have been carried out. PL spectra have been obtained at 4K, 77K and 300K, for both n–and p–type GaAs, for laser energy densities 0 ≤ El ≤ 0.6 J/cm2. It is found that PLA of crystalline (c−) GaAs alters the PL spectrum and decreases the PL intensity, corresponding to an increase in density of non-radiative recombination centers with increasing El. The variation of PL intensity with El is found to be different for n– and p–type material. No PL is observed from high dose (1 or 5×1015 ions/cm2 ) Sior Zn-implanted GaAs, either before or after laser annealing. The results suggest that the ion implantation step is primarily responsible for formation of defects associated with the loss of radiative recombination, with pulsed annealing contributing only secondarily.

A Channeling Study of Defect-Boron Complexes in Si

1980 ◽  
Vol 2 ◽  
Author(s):  
M.L. Swanson ◽  
L.M. Howe ◽  
F.W. Saris ◽  
A.F. Quenneville
Keyword(s):  
Ion Implantation ◽  
Nuclear Reaction ◽  
Incident Energy ◽  
Ruby Laser ◽  
Laser Annealing ◽  
Surface Region ◽  
Alpha Particles ◽  
Near Surface ◽  
Annealing Temperatures ◽  
Boron Complexes

ABSTRACTSi crystals were doped with 0.1–0.2 at% 11B in the near surface region by ion implantation followed by thermal diffusion at 1373 K or by ruby laser annealing. The position of the B atoms in the Si lattice was determined by channeling measurements, utilizing both the yield of H+ ions (of incident energy 0.7 MeV) backscattered from Si atoms and the yield of alpha particles from the 11B(p,α)8Be nuclear reaction. Initially, 95–99% of the B atoms were substitutional. Irradiation at 35 K or 293 K with 0.7 MeV H+ displaced B atoms from lattice sites. The displacement rate was greater at 293 K than at 35 K, and was greater for diffused samples than for laser annealed samples. Following 35 K irradiations, a large increase in the fraction fdB of displaced B atoms occurred during annealing near 240 K. At higher annealing temperatures, fdB decreased over a broad temperature range from 425–825 K. Angular scans through <110> channels for the laser annealed samples after 293 K irradiation or after 35 K irradiation plus 293 K annealing showed a pronounced narrowing of the dip in 11B(p,α)8Be yields compared with the dip in yields from Si, whereas no narrowing was observed for <100> channels. These results indicate that B atoms were displaced into specific lattice sites by the migration of an interstitial B defect (the EPR G28 defect) near 240 K.

Defects Introduced by Plasma Processing of Silicon

1992 ◽  
Vol 262 ◽  
Author(s):  
J. L. Benton
Keyword(s):  
Bulk Material ◽  
Surface Region ◽  
Surface Damage ◽  
Near Surface ◽  
Enhanced Diffusion ◽  
Interstitial Defect ◽  
Comprehensive Picture ◽  
Reaction Region ◽  
Defect Reactions ◽  
P Type

ABSTRACTThe electrical and optical properties of defects introduced by Reactive Ion Etching (RIE) in the near surface region of Si after dry etching with various gases and plasma conditions is studied with spreading Resistance (SR), photoluminescence (PL), and capacitance-voltage profiling (C-V). Plasma etching in chlorine and fluorine based gases produce donors at the surface in both n-type and p-type, Czochralski and float-zone silicon. Isochronal annealing reveals the presence of two distinct regions of dopant compensation. The surface damage region is confined to 1000 Å and survives heat treatment at 400°C, while the defect reaction region extends ≥ 1 μm in depth and recovers by 250°C. A comprehensive picture of the interstitial defect reactions in RIE silicon is completed. The interstitial defects, Ci and Bi, created in the ion damaged near surface region, undergo recombination enhanced diffusion caused by the presence of ultraviolet light in the plasma, resulting in the long range diffusion into the Si bulk. Subsequently, the interstitial atoms are trapped by the background impurities forming the defect pairs, CiOi, CSCi, or BiOi, which are observed experimentally. The depth of the diffusion-limited trapping and the probability of forming specific pairs depends on the relative concentrations of the reactants, oxygen, carbon or boron, present in the bulk material.

Electrical and Structural Characterization of Boron Implanted Silicon Following Laser Thermal Processing

2002 ◽  
Vol 717 ◽  
Author(s):  
K. A. Gable ◽  
K. S. Jones ◽  
M. E. Law ◽  
L. S. Robertson ◽  
S. Talwar
Keyword(s):  
Melting Temperature ◽  
Thermal Processing ◽  
Laser Annealing ◽  
Substrate Surface ◽  
Surface Region ◽  
Process Window ◽  
Near Surface ◽  
Dopant Activation ◽  
Transmission Electron ◽  
Laser Thermal Processing

AbstractOne alternative to conventional rapid thermal annealing (RTA) of implants for ultra-shallow junction formation is that of laser annealing. Laser thermal processing (LTP) incorporates an excimer pulsed laser capable of melting the near surface region of the silicon (Si) substrate. The melt depth is dependent upon the energy density supplied by the irradiation source and the melting temperature of the substrate surface. A process window associated with this technique is able to produce similar junction depths over a range of energy densities due to the melting temperature depression established with pre-amorphization of the substrate surface prior to dopant incorporation. The process window of germanium (Ge) preamorphized, boron (B) doped Si was investigated. 200 mm (100) n-type Si wafers were preamorphized via 18 keV Ge+ implantation to 1x1015/cm2 and subsequently implanted with 1 keV B+ to doses of 1x1015/cm2, 3x1015/cm2, 6x1015/cm2, and 9x1015/cm2. The wafers were laser annealed from 0.50 J/cm2 to 0.88 J/cm2 using a 308 nm XeCl excimer irradiation source. Transmission electron microscopy (TEM) was used to determine the process window for each implant condition, and correlations between process window translation and impurity concentration were made. Four-point probe quantified dopant activation and subsequent deactivation upon post-LTP furnace annealing.

Low Temperature Crystallization of Amorphous Silicon Films Using an Excimer Laser

1989 ◽  
Vol 149 ◽  
Author(s):  
S. E. Ready ◽  
J. B. Boyce ◽  
R. Z. Bachrach ◽  
R. I. Johnson ◽  
K. Winer ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Excimer Laser ◽  
Laser Energy ◽  
Amorphous Material ◽  
Surface Region ◽  
Silicon Films ◽  
Starting Material ◽  
Near Surface ◽  
Silicon Thin Films ◽  
Crystallite Sizes

ABSTRACTIn an effort to enhance the electrical properties of silicon thin films, we have performed recrystallization experiments on a variety of amorphous silicon films using an excimer laser. The intense, pulsed UV produced by the laser (308nm, using XeCl gas) is highly absorbed by the amorphous material and thus provides intense localized heating in the near surface region. Two types of starting films were studied: plasma CVD a-Si:H and LPCVD a-Si. The subsequent modification produces crystallites whose structure and electrical characteristics vary due to starting material and laser scan parameters. The treated films have been characterized using Raman, x-ray diffraction, TEM, SIMS and transport measurements. The results indicate that crystallites nucleate in the surface region. The degree of crystallization near the surface increases dramatically as a function of deposited laser energy density and less so as a function of laser shot density. The hall mobility of the highly crystallized samples exhibit an increase of 2 orders of magnitude over the amorphous starting material. In the PECVD material, the rapid diffusion of hydrogen causes voids to be formed at intermediate laser energy densities and removal of film at higher energy densities. The LPCVD material withstands the high laser energies to produce well crystallized films with crystallite sizes greater then 1000Å.

Effect of c-Si1-xGex Thickness Grown by LPCVD on the Performance of Thin-Film a-Si/c-Si1-xGex/c-Si Heterojunction Solar Cells

2012 ◽  
Vol 1447 ◽  
Author(s):  
Sabina Abdul Hadi ◽  
Pouya Hashemi ◽  
Nicole DiLello ◽  
Ammar Nayfeh ◽  
Judy L. Hoyt
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Layer Thickness ◽  
Surface Region ◽  
Absorber Layer ◽  
Buffer Layers ◽  
Optical Carrier ◽  
Near Surface ◽  
Heterojunction Solar Cells ◽  
P Type

ABSTRACTIn this paper the effect of Si1-xGex absorber layer thickness on thin film a-Si:H/crystalline-Si1-xGex/c-Si heterojunction solar cells (HIT cells) is studied by simulation and experiment. Cells with 1, 2 and 4 μm-thick epitaxial cap layers of p-type Si0.59Ge0.41 on top of 5 μm Si1-xGex graded buffer layers are fabricated and compared to study the effect of the absorber layer thickness. The results show no change in Voc (0.41V) and that Jsc increases from 17.2 to 18.1 mA/cm2 when the Si0.59Ge0.41 absorber layer thickness is increased from 1 to 4 μm. The effect of thickness on Jsc is also observed for 2 and 4 μm-thick Si and Si0.75Ge0.25 absorber layers. Experiments and simulations show that larger Ge fractions result in a higher magnitude and smaller thickness dependence of Jsc, due to the larger absorption coefficient that increases optical carrier generation in the near surface region for larger Ge contents.

Effect of N2 Plasma Treatments on Dry Etch Damage in n- and p-type GaN

2000 ◽  
Vol 639 ◽  
Author(s):  
D.G. Kent ◽  
K.P. Lee ◽  
A.P. Zhang ◽  
B. Luo ◽  
M.E. Overberg ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Schottky Diodes ◽  
Surface Region ◽  
Chemical Effect ◽  
Near Surface ◽  
Current Voltage ◽  
Extent Of Damage ◽  
P Type ◽  
Dry Etch ◽  
N2 Plasma

ABSTRACTThe extent of damage recovery by N2 plasma treatment of previously damaged n- and p-GaN has been examined using current-voltage (I-V) characteristics from Schottky diodes. There are two contributions to the observed improvement in the I-V characteristics, namely a simple annealing effect and also a chemical effect from reactive nitrogen. However the N2 plasma treatment does not fully restore the initial electrical properties of the near-surface region.

Nonmelt Laser Annealing of 1 Kev Boron Implanted Silicon

2001 ◽  
Vol 669 ◽  
Author(s):  
Susan Earles ◽  
Mark Law ◽  
Kevin Jones ◽  
Somit Talwar ◽  
Sean Corcoran
Keyword(s):  
Laser Annealing ◽  
Laser Energy ◽  
High Dose ◽  
Ramp Rate ◽  
Dopant Activation ◽  
Pulsed Laser Annealing ◽  
Transmission Electron ◽  
Ultra Shallow Junctions ◽  
Defect Nucleation ◽  
Probe Measurements

ABSTRACTHeavily-doped, ultra-shallow junctions in boron implanted silicon using pulsed laser annealing have been created. Laser energy in the nonmelt regime has been supplied to the silicon surface at a ramp rategreater than 1010°C/sec. This rapid ramp rate will help decrease dopant diffusion while supplying enough energy to the surface to produce dopant activation. High-dose, non-amorphizing 1 keV, 1e15 ions/cm2 boron is used. Four-point probe measurements (FPP) show a drop in sheet resistance withnonmelt laser annealing (NLA) alone. Transmission electron microscopy (TEM) shows the NLA dramatically affects the defect nucleation resulting in fewer defects with post annealing. Hall mobility and secondary ion mass spectroscopy (SIMS) results are also shown.

Characterization of Si, SiGe and SOI Structures Using Photoluminescence

1999 ◽  
Vol 588 ◽  
Author(s):  
V. Higgs
Keyword(s):  
Focused Ion Beam ◽  
Secondary Ion Mass Spectrometry ◽  
Ion Beam ◽  
Surface Region ◽  
Misfit Dislocations ◽  
Near Surface ◽  
Pl Mapping ◽  
Excitation Laser ◽  
Pl Intensity ◽  
P Type

AbstractA new Photoluminescence (PL) method has been developed to detect defects in the near surface region of Si wafers and Si-on-insulator (SOI) structures. Wafer maps (up to 300 min diameter) can be readily acquired and areas of interest can be scanned at high resolution (≈1 μm). The excitation laser beam is modulated to confine the photogenerated carriers; defects are observed due to the localised reduction of the carrier lifetime. Si p-type (10 Ohm.cm) wafers were intentionally contaminated with various levels of Ni and Fe (1×109−5×1010 atoms/cm2) and annealed. The PL intensity was observed to decrease due to the metal related non-radiative defects. Whereas in contrast, for Cu, (1×109−5×1010 atoms/cm2) the PL intensity actually increased initially and reached a maximum value at 5×109 atoms/cm2. It is suggested that during contamination the Cu related defects have complexed with existing defects (that have stronger recombination properties) and increased the PL. Further Cu contamination (1×1010−5×1010 atoms/cm2) produced a reduction in the PL intensity. PL mapping of strained SiGe epilayers showed that misfit dislocations can be detected and PL can be used to evaluate material quality.PL maps of SOI bonded wafers revealed that the non-bonded areas, voids or gas bubbles could be detected. This was confirmed using defect etching and polishing, voids as small as ≈30 μm in diameter could be detected. SOI wafers fabricated using the separation by implanted oxygen (SIMOX) technique were also analysed, variations in the recombination properties of the layer could be observed. Further inspection using transmission electron microscopy (TEM) revealed that the defects were non-uniformities of the buried oxide covering several microns and containing tetrahedral stacking faults. Focused ion beam (FIB) milling and secondary ion mass spectrometry (SIMS) showed that these defects were at the Si/SiO2 interface and were chemically different to the surrounding area.

Electrical Properties of Epitaxial Silicide-Silicon Interfaces

1985 ◽  
Vol 54 ◽  
Author(s):  
R. T. Tung ◽  
A. F. J. Levi ◽  
J. M. Gibson ◽  
K. K. Ng ◽  
A. Chantre
Keyword(s):  
Fermi Level ◽  
Single Crystal ◽  
Schottky Barrier ◽  
Surface Region ◽  
Ideal Behavior ◽  
Near Surface ◽  
Barrier Heights ◽  
Transmission Electron ◽  
Current Voltage ◽  
P Type

ABSTRACTThe Schottky barrier heights of single crystal NiSi2 layers on Si(111) have been studied by current-voltage, capacitance-voltage and activation energy techniques. Near ideal behavior is found for Schottky barriers grown on substrates cleaned at ∼820°C in ultrahigh vacuum. The Fermi level positions at the interfaces of single crystal type A and type B NiSi2 are shown to differ by ∼0.14 eV. Transmission electron microscopy demonstrated the epitaxial perfection of these suicide layers. At a cleaning temperature of 1050° C, the near surface region of lightly doped n-type Si was converted to p-type. The presence of a p-n junction was directly revealed by spreading resistance measurements and resulted in a high apparent Schottky barrier height (≥0.75 eV) which no longer bears immediate relationship to the interface Fermi level position.

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