[ { "id": "authors:8y1pc-yxm34", "collection": "authors", "collection_id": "8y1pc-yxm34", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BAIjap92b", "type": "article", "title": "Generation and recovery of strain in (28)Si-implanted pseudomorphic GeSi films on Si(100)", "author": [ { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" }, { "family_name": "Nicolet", "given_name": "M.-A.", "clpid": "Nicolet-M-A" } ], "abstract": "Effects of ion implantation of 320 keV Si-28 at room temperature in pseudomorphic metastable GexSi1-x (x almost-equal-to 0.04, 0.09, 0.13) layers approximately 170 nm thick grown on Si(100) wafers were characterized by x-ray double-crystal diffractometry and MeV He-4 channeling spectrometry. The damage induced by implantation produces additional compressive strain in the GexSi1-x layers, superimposed on the intrinsic compressive strain of the heterostructures. This strain rises with the dose proportionally for doses below several times 10(14) Si-28/cm2. Furthermore, for a given dose, the strain increases with the Ge content in the layer. Upon thermal processing, the damage anneals out and the strain recovers to the value before implantation. Amorphized samples (doses of greater than 2 x 10(15) Si-28/cm2) regrow poorly.", "doi": "10.1063/1.350802", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "1992-05-01", "series_number": "9", "volume": "71", "issue": "9", "pages": "4227-4229" }, { "id": "authors:dq6cx-hgd60", "collection": "authors", "collection_id": "dq6cx-hgd60", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BAIjap92a", "type": "article", "title": "Damage production and annealing in 28Si-implanted CoSi2/Sim(111) heterostructures", "author": [ { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" }, { "family_name": "Nicolet", "given_name": "M.-A.", "clpid": "Nicolet-M-A" } ], "abstract": "The damage in epitaxial CoSi2 films 500 nm thick grown on Si(111) produced by room-temperature implantation of 150 keV 28Si were investigated by 2-MeV 4He channeling spectrometry, double-crystal x-ray diffractometry, and electrical resistivity measurements. The damage in the films can be categorized into two types. In lightly (heavily) damaged CoSi2 the damage is in the form of point-like (extended) defects. The resistivity of lightly damaged CoSi2 films rises with the dose of implantation. Electrical defects correlate well with structural ones in lightly damaged films. The resistivity of heavily damaged films flattens off while the structural defects continue to rise with the dose, so that resistivity no longer correlates with structural defects. Upon thermal annealing, lightly damaged films can fully recover structurally and electrically, whereas heavily damaged films do so only electrically. A residual structural damage remains even after annealing at 800 \u00b0C for 60 min.", "doi": "10.1063/1.351325", "issn": "0021-8979", "publisher": "American Institute of Physics", "publication": "Journal of Applied Physics", "publication_date": "1992-01-15", "series_number": "2", "volume": "71", "issue": "2", "pages": "670-675" }, { "id": "authors:xdahv-73d04", "collection": "authors", "collection_id": "xdahv-73d04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BAIjap91c", "type": "article", "title": "Defect production in Si(100) by 19F, 28Si, 40Ar, and 131Xe implantation at room temperature", "author": [ { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" }, { "family_name": "Nicolet", "given_name": "M.-A.", "clpid": "Nicolet-M-A" } ], "abstract": "We used x-ray double-crystal diffractometry and MeV 4He channeling spectrometry to study quantitatively the damage produced in Si(100) at room temperature by 230-keV 19F, 230-keV 28Si, 250-keV 40Ar, or 570-keV 131Xe implantation. The measured defect concentration and the perpendicular strain have the same depth profile, and both are depleted near the surface compared to the Frenkel pair concentration calculated from computer simulation. The perpendicular strain is proportional to the defect concentration with a coefficient of B~0.01 common to all implanted species. The maximum value of the perpendicular strain and of the defect concentration rises nonlinearly with the dose for all species. The damage produced by different implanted species depends on the dose in approximately the same way save for a scaling factor of the dose. In the regime of low damage, the strain and the defect concentration rise linearly with increasing dose. The slope of this rise with dose increases with the square of the Frenkel pairs produced per unit dose of incident ions, as calculated from computer simulations. This fact means that stable defects produced by room-temperature implantation in Si(100) cannot be predicted by a linear cascade model.", "doi": "10.1063/1.349251", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "1991-10-01", "series_number": "7", "volume": "70", "issue": "7", "pages": "3551-3555" }, { "id": "authors:4fzx0-x8b88", "collection": "authors", "collection_id": "4fzx0-x8b88", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BAIjap91b", "type": "article", "title": "Defects production and annealing in self-implanted Si", "author": [ { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" }, { "family_name": "Nicolet", "given_name": "M.-A.", "clpid": "Nicolet-M-A" } ], "abstract": "230-keV 28Si ions were implantated into Si(100) at room temperature with doses from 1014 to 1015/cm2. The samples were analyzed by x-ray double crystal diffractometry and 2-MeV 4He ion channeling spectrometry. The implanted layer has a parallel lattice spacing equal to that of the unimplanted substrate. The perpendicular lattice spacing is larger than that of the unimplanted substrate and is proportional to the defect concentration extracted from the channeling measurement. Both the perpendicular lattice spacing and the defect concentration increase nonlinearly with ion dose. The defect concentration initially increases slowly with dose until a critical value (~15%, at 4\u00d71014/cm2), then rises rapidly, and finally a continuous amorphous layer forms. The initial sluggish increase of the damage is due to the considerable recombination of point defects at room temperature. The rapid growth of the defect concentration is attributed to the reduction of the threshold energy for atomic displacement in a predamaged crystal. The amorphization is envisioned as a cooperative process initiated by a spontaneous collapse of heavily damaged crystalline regions. The annealing behavior of the damaged layer reveals various stages of defect recovery, indicating that the damage consists of a hierarchy of various defect structures of vacancy and interstitial aggregates.", "doi": "10.1063/1.349668", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "1991-07-15", "series_number": "2", "volume": "70", "issue": "2", "pages": "649-655" }, { "id": "authors:9348x-8gx80", "collection": "authors", "collection_id": "9348x-8gx80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BAIjap91a", "type": "article", "title": "Elastic and thermal properties of mesotaxial CoSi2 layers on Si", "author": [ { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" }, { "family_name": "Nicolet", "given_name": "M.-A.", "clpid": "Nicolet-M-A" }, { "family_name": "Vreeland", "given_name": "T., Jr.", "clpid": "Vreeland-T-Jr" } ], "abstract": "Single crystalline 110 nm thick CoSi2 layers formed on both (100)- and (111)-oriented Si wafers by high dose 59Co implantation and thermal annealing were analyzed by x-ray double crystal diffractometry. The lateral mismatch of both (100)- and (111)-oriented samples are similar (~\u20130.7%) at room temperature, meaning that the average spacing between misfit dislocations is roughly the same (~30 nm). But the perpendicular mismatch differs for the two substrate orientations, reflecting the elastic anisotropy of the single-crystalline CoSi2 layers. The three elastic constants of cubic CoSi2 (C11 = 277, C12C12= 222, C44 = 100 GPa) were extracted from these lattice mismatches and the sample curvature measurements. X-ray rocking curves were also recorded up to ~500 \u00b0C. The average spacing between the misfit dislocations remains unchanged, meaning that the misfit dislocations do not shear up to 500 \u00b0C. The linear thermal expansion coefficient of CoSi2 (9.5 \u00d7 10^\u20136/\u00b0C) was obtained under the assumption that the elastic constants do not change with temperature.", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "1991-05-01", "series_number": "9", "volume": "69", "issue": "9", "pages": "6451-6455" }, { "id": "authors:tjyr6-wcm94", "collection": "authors", "collection_id": "tjyr6-wcm94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120509-133504606", "type": "article", "title": "Reflection high-energy electron diffraction patterns of CrSi_2 films on (111) silicon", "author": [ { "family_name": "Mahan", "given_name": "John E.", "clpid": "Mahan-J-E" }, { "family_name": "Geib", "given_name": "Kent M.", "clpid": "Geib-K-M" }, { "family_name": "Robinson", "given_name": "G. Y.", "clpid": "Robinson-G-Y" }, { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" }, { "family_name": "Nicolet", "given_name": "M-A.", "clpid": "Nicolet-M-A" } ], "abstract": "Highly oriented films of the semiconducting transition metal silicide, CrSi2, were grown on (111) silicon substrates, with the matching crystallographic faces being CrSi_2(001)/Si(111). Reflection high\u2010energy electron diffraction (RHEED) yielded symmetric patterns of sharp streaks. The expected streak spacings for different incident RHEED beam directions were calculated from the reciprocal net of the CrSi_2(001) face and shown to match the observed spacings. The predominant azimuthal orientation of the films was thus determined to be CrSi_2\u3008210\u3009\u2225Si\u3008110\u3009. This highly desirable heteroepitaxial relationship may be described with a common unit mesh of 51 \u00c5^2 and a mismatch of \u22120.3%. RHEED also revealed the presence of limited film regions of a competing azimuthal orientation, CrSi_2\u3008110\u3009\u2225Si\u3008110\u3009. A new common unit mesh for this competing orientation is suggested; it possesses an area of 612 \u00c5^2 and a mismatch of \u22121.2%.", "doi": "10.1116/1.585791", "issn": "1071-1023", "publisher": "American Vacuum Society", "publication": "Journal of Vacuum Science and Technology B", "publication_date": "1991-01", "series_number": "1", "volume": "9", "issue": "1", "pages": "64-68" }, { "id": "authors:n5jez-kex33", "collection": "authors", "collection_id": "n5jez-kex33", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BAIapl90", "type": "article", "title": "Radiation damage in ReSi2 by a MeV 4He beam", "author": [ { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" }, { "family_name": "Nicolet", "given_name": "M-A.", "clpid": "Nicolet-M-A" }, { "family_name": "Mahan", "given_name": "John E.", "clpid": "Mahan-J-E" }, { "family_name": "Geib", "given_name": "Kent M.", "clpid": "Geib-K-M" }, { "family_name": "Robinson", "given_name": "Gary Y.", "clpid": "Robinson-G-Y" } ], "abstract": "Epitaxial ReSi2 thin films grown on Si (100) substrates were analyzed at room temperature by MeV 4He backscattering and channeling spectrometry. The minimum yield of [100] axial channeling increases with increasing exposure of the ReSi2 sample to the analyzing He beam. This means that ReSi2 suffers irradiation damage induced by a MeV 4He beam. The damage in the film induced by a beam incident along a random direction is about one order of magnitude larger than that induced by a beam with an aligned incidence, indicating that the damage is mainly generated by elastic collisions of nuclei. The experimentally measured defect concentration produced at 300 K by a beam of random incidence is compared with the theoretically estimated one produced at 0 K in an amorphous target. The agreement is fairly good, suggesting that the defects are stable at room temperature.", "doi": "10.1063/1.104134", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "1990-10-15", "series_number": "16", "volume": "57", "issue": "16", "pages": "1657-1659" }, { "id": "authors:4pex3-vr798", "collection": "authors", "collection_id": "4pex3-vr798", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BAIprb90", "type": "article", "title": "Channeling of MeV ions in polyatomic epitaxial films: ReSi2 on Si(100)", "author": [ { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" }, { "family_name": "Nicolet", "given_name": "M.-A.", "clpid": "Nicolet-M-A" }, { "family_name": "Mahan", "given_name": "John E.", "clpid": "Mahan-J-E" }, { "family_name": "Geib", "given_name": "Kent M.", "clpid": "Geib-K-M" } ], "abstract": "Channeling of a He beam in the energy range from 1.4 to 2.7 MeV in a polyatomic epitaxial ReSi2 film (\u223c150 nm thick) was studied by detecting backscattered He ions. The critical angles and the minimum yields of both the heavy (Re) and the light (Si) elements are obtained directly from backscattering measurements. The critical angles of both Re and Si scale as \u221a1/E. The critical angle of Re is always about 2.3 times that of Si. The minimum yields of both Re and Si do not change over this energy range. The minimum yield of Re (2%) is about 1/7 that of Si (14%). The results are explained qualitatively and quantitatively by the continuum model suitably extended for polyatomic crystals. An important corollary is that a high value for the minimum yield of the light element in a polyatomic single crystal does not necessarily mean that the sublattice of the light element is disordered.", "doi": "10.1103/PhysRevB.41.8603", "issn": "0163-1829", "publisher": "Physical Review B", "publication": "Physical Review B", "publication_date": "1990-05-01", "series_number": "13", "volume": "41", "issue": "13", "pages": "8603-8607" }, { "id": "authors:xrmae-9xk23", "collection": "authors", "collection_id": "xrmae-9xk23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ZHOprb89", "type": "article", "title": "Excitonic transitions in GaAs-AlxGa1-xAs multiple quantum wells affected by interface roughness", "author": [ { "family_name": "Zhou", "given_name": "P.", "clpid": "Zhou-P" }, { "family_name": "Jiang", "given_name": "H. X.", "clpid": "Jiang-H-X" }, { "family_name": "Bannwart", "given_name": "R.", "clpid": "Bannwart-R" }, { "family_name": "Solin", "given_name": "S. A.", "clpid": "Solin-S-A" }, { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" } ], "abstract": "Time-resolved photoluminescence has been used to study the effects of interface roughness on excitonic transitions in GaAs-AlxGa1-xAs multiple quantum wells. In addition to the luminescence linewidth broadening and Stokes red shift, the interface roughness also strongly affects the dynamic process of optical transitions so that the excitonic transition peak shifts with delay time. However, the heavy-hole exciton transition has red shifts at short delay times and exhibits a turnover at longer delay times. A maximum shift of about 0.1 meV at a delay time of 4 ns was obtained. We have demonstrated that the peak shift is caused by interface roughness in the quantum wells. Furthermore, the decay of the excitonic transition is found to fit a two-exponential form. Based on a model involving interface roughness and two-exponential decay, we calculated the position of the excitonic transition peak as a function of delay time. Our calculations are consistent with experimental results.", "doi": "10.1103/PhysRevB.40.11862", "issn": "0163-1829", "publisher": "Physical Review B", "publication": "Physical Review B", "publication_date": "1989-12-15", "series_number": "17", "volume": "40", "issue": "17", "pages": "11862-11867" }, { "id": "authors:v66s2-dbp62", "collection": "authors", "collection_id": "v66s2-dbp62", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:TANjvstb89", "type": "article", "title": "Activation analysis of rapid thermally annealed Si and Mg implanted semi-insulating GaAs", "author": [ { "family_name": "Tandon", "given_name": "J. L.", "clpid": "Tandon-J-L" }, { "family_name": "Leybovich", "given_name": "I. S.", "clpid": "Leybovich-I-S" }, { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" } ], "abstract": "Electronic properties of Si and Mg implants in undoped semi-insulating GaAs are studied. The activation of the implants is achieved by rapid thermal annealing. The effects of implantation dose and anneal temperature on the measured electrical activity are investigated. In spite of similar depth distributions and implantation damage characteristics, a marked difference between the activations of the Si and the Mg ions is observed for the dose range considered (3\u00d710^12 \u2013 1\u00d710^14 cm^\u20132). Lattice strain measurements performed by x-ray rocking curves indicate that the residual implantation damage after annealing is not largely responsible for this difference. The difference is mostly electronic in character, as also suggested by photoluminescence measurements. At high annealing temperatures, changes in the compensating properties of undoped semi-insulating GaAs are suspected, and are found to play an important role in the activation of implanted ions, affecting the n- and p-type dopants conversely.", "doi": "10.1116/1.584556", "issn": "1071-1023", "publisher": "American Vacuum Society", "publication": "Journal of Vacuum Science and Technology B", "publication_date": "1989-09", "series_number": "5", "volume": "7", "issue": "5", "pages": "1090-1095" }, { "id": "authors:ennf2-eqj26", "collection": "authors", "collection_id": "ennf2-eqj26", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MIIjvstb89", "type": "article", "title": "Growth and characterization of doped GaAs/AlGaAs multiple quantum well structures on Si substrates for infrared detection", "author": [ { "family_name": "Mii", "given_name": "Y. J.", "clpid": "Mii-Y-J" }, { "family_name": "Karunasini", "given_name": "R. P> G.", "clpid": "Karunasini-R-P-G" }, { "family_name": "Wang", "given_name": "K. L.", "clpid": "Wang-K-L" }, { "family_name": "Bai", "given_name": "Gang", "clpid": "Bai-G" } ], "abstract": "Doped GaAs/AlGaAs multiple quantum well structures were grown on Si substrates by molecular-beam epitaxy. The crystallinity of the epitaxial layers was examined by cross-sectional transmission electron microscopy and an x-ray rocking curve technique. The threading dislocation density of the multiple quantum well region was estimated to be 108 cm\u20132 by transmission electron microscopy. The x-ray rocking curve measurement revealed a full width at half-maximum of 380 arcsec, with no superlattice peak observed. Electrical and optical characterizations by tunneling current and intersubband infrared absorption showed comparable properties with similar structures grown directly on a GaAs substrate. The effect of crystallinity on the electrical and optical properties of the multiple quantum well structures is discussed.", "doi": "10.1116/1.584746", "issn": "1071-1023", "publisher": "American Vacuum Society", "publication": "Journal of Vacuum Science and Technology B", "publication_date": "1989-03", "series_number": "2", "volume": "7", "issue": "2", "pages": "341-344" }, { "id": "authors:6276d-mdp60", "collection": "authors", "collection_id": "6276d-mdp60", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:TANapl89.965", "type": "article", "title": "Sequential nature of damage annealing and activation in implanted GaAs", "author": [ { "family_name": "Tandon", "given_name": "J. L.", "clpid": "Tandon-J-L" }, { "family_name": "Madok", "given_name": "J. H.", "clpid": "Madok-J-H" }, { "family_name": "Leybovich", "given_name": "I. S.", "clpid": "Leybovich-I-S" }, { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" }, { "family_name": "Nicolet", "given_name": "M-A.", "clpid": "Nicolet-M-A" } ], "abstract": "Rapid thermal processing of implanted GaAs reveals a definitive sequence in the damage annealing and the electrical activation of ions. Removal of implantation-induced damage and restoration of GaAs crystallinity occurs first. Irrespective of implanted species, at this stage the GaAs is n-type and highly resistive with almost ideal values of electron mobility. Electrical activation is achieved next when, in a narrow anneal temperature window, the material becomes n- or p-type, or remains semi-insulating, commensurate to the chemical nature of the implanted ion. Such a two-step sequence in the electrical doping of GaAs by ion implantation may be unique of GaAs and other compound semiconductors.", "doi": "10.1063/1.100948", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "1989-01-30", "series_number": "5", "volume": "54", "issue": "5", "pages": "448-450" }, { "id": "authors:0banr-bsx83", "collection": "authors", "collection_id": "0banr-bsx83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150312-080542685", "type": "monograph", "title": "Characterization of Semiconductors by MeV He+ Backscattering Spectrometry, Channeling and Double Crystal Diffraction", "author": [ { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" }, { "family_name": "Tsai", "given_name": "C.-J.", "clpid": "Tsai-C-J" }, { "family_name": "Dommann", "given_name": "A.", "clpid": "Dommann-A" }, { "family_name": "Nicolet", "given_name": "M-A.", "clpid": "Nicolet-M-A" }, { "family_name": "Vreeland", "given_name": "T., Jr.", "clpid": "Vreeland-T-Jr" } ], "abstract": "Double Crystal Diffractometry (DCD) is used to characterize the strain produced by 2 MeV He+ at room temperature to simulate a Rutherford Backscattering Spectrometry (RBS) analysis of bulk Si, Ge and GaAs. The irradiation-induced strain is very small in both Si and Ge and persists after 15 min annealing at 400\u00b0C. The strain is significant in GaAs and largely reversible upon annealing. The capabilities of DCD are further demonstrated on an example involving characterization of a CoSi_2 epilayer grown on a Si(111) substrate whose surface is slightly offset from the (111) plane by an angle \u00f8_s, in the [110] direction. There is a very small misorientation between the Si(111) and CoSi_2(111) planes. The misorientation angle, \u03b1, between these two planes is a fixed fraction 0.017 of the offset angle, \u00f8_s up to \u00f8_s = 4\u00b0. A simple geometrical model is proposed to explain the observation. The model agrees quantitatively with the experiment.", "publisher": "Caltech Library", "publication_date": "1987" }, { "id": "authors:69xpq-qxc87", "collection": "authors", "collection_id": "69xpq-qxc87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150304-090025874", "type": "book_section", "title": "Defects Annealing of Si^+ Implanted GaAs at RT and 100\u00b0C", "book_title": "Materials Modification and Growth Using Ion Beams", "author": [ { "family_name": "Bai", "given_name": "G.", "clpid": "Bai-G" }, { "family_name": "Jamieson", "given_name": "D. N.", "clpid": "Jamieson-D-N" }, { "family_name": "Nicolet", "given_name": "M-A.", "clpid": "Nicolet-M-A" }, { "family_name": "Vreeland", "given_name": "T., Jr.", "clpid": "Vreeland-T-Jr" } ], "contributor": [ { "family_name": "Gibson", "given_name": "Ursula Jane", "clpid": "Gibson-U-J" }, { "family_name": "White", "given_name": "Alice E.", "clpid": "White-A-E" }, { "family_name": "Pronko", "given_name": "Peter P.", "clpid": "Pronko-P-P" } ], "abstract": "Annealing behavior of point defects near room temperature is studied by measuring the strain relaxation of Si+ implanted GaAs. Polished semi-insulating GaAs wafers were implanted with 300keV Si^+ at liquid nitrogen (LN_2) and room temperature (RT). The strain profile was obtained by the X-ray Double Crystal Diffraction (DCD) technique and kinematical fitting. The maximum strain of the samples stored at RT and elevated temperature 100\u00b0C in air, decreases with time, which indicates the reduction of point defects. Relaxation is exponential in time. At least two time constants of 0.24hrs and 24hrs are needed to fit the data, suggesting that two different processes are responsible for annealing defects. Time constants are obtained for different doses at RT and LN_2 implantation temperature, and found to be insensitive to both these quantities. The activation energy for defect migration is estimated using simple diffusion model.", "doi": "10.1557/PROC-93-67", "isbn": "9780931837609", "publisher": "Materials Research Society", "place_of_publication": "Pittsburgh, PA", "publication_date": "1987", "pages": "67-72" } ]