bluuebunny/crossref_metadata_2025_split huggingface dataset:
TEM Study of MOCVD Grown InSb/GaAs Heterostructures with and without TMIn Predeposited Layers
Authors: Kuo L. H. , Hua Susan Z. , Salamanca-Riba L. , Partin D. L. , Green L. , Heremans J. 
Published: April 2011

ABSTRACTHigh quality InSb epilayers were grown on GaAs substrates by metal organic chemical vapor deposition using a two-step growth procedure involving trimethal indium (TMIn) predeposition. From transmission electron microscopy studies, we found that an interdiffusion layer of thickness of 10 Å forms at the interface when the substrate is exposed to TMIn for approximately 6 secs prior to the growth of the InSb filns. Hall mobilities up to σ 52,000 cm2/V-s were obtained at 300 K on a 2.1-μm-thick InSb heteroepitaxial film. In contrast, samples without TMIn predeposition showed polycrystallinity of the InSb films grown on single crystalline GaAs substrates. The effect. of TMNIn predeposition is to minimize the misorientation of the grains, suppress the polycrystallinity, decrease the density of threading dislocations, and increase the electron mobilities in the films. However, we found that too much TMIn predeposition gives rise t.o an intermixing layer at the InSb/GaAs interface which deteriorates the film quality. Details of the effect of the TMIn predeposition on the microstructure of InSb/GaAs with different predeposition times (zero, 6, and 12 secs) are discussed.
A Monte Carlo Model of GaAs [111]B Epitaxy
Authors: Dorsey Donald L. , Venkatasubramanian R. , Yen M.Y. , Haas T.W. 
Published: April 2011

ABSTRACTThe Monte Carlo (MC) technique has been frequently used to model semiconductor thin-film epitaxy, especially for the cases of homo-epitaxial growth on Si (100) and GaAs (100) surfaces. In a recent paper, it was shown that excellent qualitative agreement can be obtained between the surface step density evolution as simulated by a simple cubic MC model and the experimentally observed RHEED specular intensity oscillations on stepped GaAs (100) substrates during growth by MBE [1]. The simple cubic model performs well for this case because of the rectangular arrangement of the gallium atoms in the (100) planes of the gallium sublattice. For the case of the (111) surface, however, the gallium atoms in the (111) plane of the gallium sublattice are hexagonally arranged. This system is not amenable to simulation with a simple cubic MC model. In this work, GaAs [111]B epitaxy is modeled using the MC method on a zincblende lattice. To ourknowledge this is the first application of this technique to the growth of a zincblende thin-film in the [11]B direction..The predicted surface step density evolution is compared to experimental RHEED specular intensity oscillations. The relative merits of using on-axis and off-axis substrates are explored.
Molecular Beam Epitaxy of II/VI Compounds for Blue/Green Laser Diodes
Authors: Gaines J.M. 
Published: April 2011

ABSTRACTThe growth of I1/VI epitaxial layers by molecular beam epitaxy (MBE) for blue/green lasers is described. To elucidate the issues in the growth of II/VI materials, the differences between II/V and II/VI MBE growth are addressed, including factors such as: substrates, molecular beam sources, lattice matching, sticking coefficients, and surface diffusion. Results of reflection high-energy diffraction (RHEED) oscillation measurements are presented. RHEED oscillations have proven to be a valuable in-situ tool for controlling certain aspects of 1I/VI MBE growth, such as ZnSySe1-y composition, Zn1-xMgxSe composition, and the growth rate of ZnSe during migration-enhanced epitaxy.
MBE Growth and Characterization of II-VI Blue/Green Laser Diodes Having CW Operation at Room Temperature
Authors: Ringle M.D. , Grillo D.C. , Fan Y. , He L. , Han J. , Gunshor R.L. , Salokatve A. , Jeon H. , Hovinen M. , Nurmikko A.V. , Hua G.C. , Otsuka N. 
Published: April 2011

ABSTRACTWe have obtained continuous-wave laser operation at room temperature from a (Zn,Mg)(S,Se)-based Il-VI separate-confinement heterostructure where injection of holes into the p-type quaternary was achieved through the employment of a Zn(Se,Te) graded-bandgap contact. The laser devices exhibit threshold current densities of below 300 A/cm2 and voltages below 6 V. Issues related to the control of the growth of the quaternary (Zn,Mg)(S,Se) compound, and a proposal to further reducing the laser operating voltage will also be described.
N- and P-Type Doping of ZnSe Using Gas Source Molecular Beam Epitaxy
Authors: Fisher P. A. , Ho E. , House J. L. , Petrich G. S. , Kolodziejski L. A. , Brandt M. S. , Johnson N. M. 
Published: April 2011

ABSTRACTHigh quality ZnSe:Cl has been grown on GaAs by gas source molecular beam epitaxy (GSMBE); elemental Zn and H2Se are used as source materials, with ZnCl2 as a dopant source for donors. Atomic Cl concentrations ([Cl]) approaching 1020 cm−3 have been incorporated into the lattice as indicated by secondary ion mass spectrometry (SIMS). At incorporation levels greater than 1020 cm−3, an appreciable decrease in the growth rate has been observed. The sharp transition to a negligible growth rate is attributed to the occurrence of a surface chemical reaction originating from Cl and H which are present in the GSMBE environment. For [Cl] as high as 4 x 1018 cm−3, the films exhibited high crystalline quality, as indicated by photoluminescence originating from a single intense donor-bound excitonic transition. Hydrogenation of semiconductors can potentially result in the electrical passivation of incorporated acceptor and donor species. In the case of ZnSe:Cl, H was present in the ZnSe layers, but did not appear to adversely affect the electrical properties of the n-type films. In contrast, for the growth of ZnSe:N, where a nitrogen plasma cell was employed as a source of nitrogen, the H concentration (as determined by SIMS) was observed to track the N concentration. The ZnSe:N films were highly resistive for various amounts of N incorporation, which suggests that H incorporation is an issue of primary importance in the p-type doping of ZnSe grown by GSMBE.
Highly Doped P-Type and N-Type ZnS, ZnSe, CdS and CdSe Thin Films Growth by Pulsed Laser Deposition
Authors: Shen Wenpin P. , Kwok Hoi S. 
Published: April 2011

ABSTRACTZnS, ZnSe, CdS and CdSe thin films were grown on InP or GaAs substrates with high ptype and n-type doping concentrations by pulsed excimer laser deposition without any postannealing processing. The x-ray diffraction results showed that these thin films were fully epitaxial (in-plane aligned). These high quality films are suitable for use as optoelectronic devices which will operate in the visible region of the spectrum.
Thermal Expansion Behavior of ZnSe and ZnS0.03Se0.97 Epilayers on GaAs at Temperatures in the Range, 25°C - 250°C
Authors: Kim J. R. , Park R. M. , Jones K. S. 
Published: April 2011

ABSTRACTThe thermal expansion behavior of ZnSe and ZnS0.03Se0.97 epilayers grown on GaAs has been investigated using high resolution X-ray diffraction at temperatures between room temperature and the growth temperature. The lattice parameters perpendicular and parallel to the surface were measured with the Bond's method. The lattice mismatch for a partially relaxed ZnSe layer was Δa(⊥)/a =2300 ppm and Δa(‖)/a = 2600 ppm at room temperature(R.T.) and Δa (⊥)/a =3600 ppm and Δa(‖)/a =2400 ppm at 250°C. For ZnS0.03Se0.97 which is almost lattice matched at R.T. to GaAs, Δa(⊥)/a =200 ppm, Δa(⊥)/a =20ppmatR.T. and Δa(⊥)/a =1400ppm, Δa(⊥)/a =50ppm at 250°C. The relaxed lattice constants were evaluated and the thermal expansion coefficients of relaxed ZnSe layers were found to vary from 7.8*10−6/°C at room temperature to 12.2*10−6/°C at 250°C and for ZnS0.03Se0.97 layers the variation was from 7.5*10−6/°C at R.T. to 11.7*10−6/°C at 250°C.
MOCVD Growth and Characterization of High-Quality ZnSe on GaAs
Authors: Chen J. C. , Yang Bing , Semendy F. , Clark W. W. , Boyd P. R. , Bambha N. 
Published: April 2011

ABSTRACTHigh-quality ZnSe epilayers on GaAs substrates have been grown by MOCVD. Diethylzinc (DEZn) and diethylselenide (DESe) were used as source materials. Growth studies were done at 400°C under different growth conditions in an atmospheric pressure MOCVD reactor. The as-grown ZnSe epilayers were characterized by a wide variety of techniques, such as double crystal x-ray diffraction, low-temperature photoluminescence (PL), transmission electron microscopy (TEM), secondary ion mass spectrometry (SIMS), and scanning electron microscopy (SEM).The results show excellent structural and optical properties of ZnSe. The best material was grown on undoped GaAs at the VI/II ratio near unity. The full-width-at-half-maximum (FWHM) of ZnSe (∼0.2/μm thick) x-ray peak as low as 90 arc seconds was achieved. TEM results also show very low defect density. The density of stacking faults is less than 105/cm2 which is four orders of magnitude less than that of samples grown by conventional MBE [J. Petruzzello et al. J. Appl. Phys. 63, 2299 (1988)] and MOCVD [J.L. Batstone et al. Philos. Mag A, 66, 609, 1992]. The spacing between misfit dislocations is between 5 to 10,μm which is one order of magnitude larger than that of reported sample of comparable thickness.
Optical and X-Ray Diffraction Characterization of MBE-Grown InGaAs, InAlAs and InGaAIAs on InP
Authors: Feng Z. C. , Chua S. J. , Raman A. , Lim N.N. 
Published: April 2011

ABSTRACTA variety of Inl-xGaxAs, Inl-yAlyAs and Inl-x-yGaxAlyAs films have been grown on InP by molecular beam epitaxy. A comprehensive characterization was performed using Raman scattering, photoluminescence (PL), Fourier transform infrared (FTIR) spectroscopy and double crystal X-ray diffraction on these ternary and quaternary heterostructures with different compositions and growth conditions. The lattice matched and mismatched structures are studied. Our analyses show that the interface mismatch exerts an important influence on the optical properties of these heterostructures, and conversely that Raman, PL and FTIR can be used to probe the interface mismatch nondestructively.
Current State and Future Challenge in HgCdTe MBE Technology
Authors: Wu Owen K. 
Published: April 2011

ABSTRACTSignificant progress has been made in HgCdTe MBE technology over the last two years. Device quality materials have been grown with the alloy compositions required for short-wavelength infrared (SWIR), 1-3 micron to LWIR (long-wavelength infrared), 8-12 micron applications. Indeed, the observation of low defect density (EPD<2×105/cm2), long minority carrier lifetime and efficient IR photoluminescence attests to the device quality of HgCdTe epilayers grown by MBE. In addition, the breakthroughs to achieve In (N-type) and As (P-type) doping in situ have provided greater flexibilities for fabricating advanced heterojunction devices. High performance IR imaging arrays have been fabricated and IR images were obtained. Also, dual-band detectors and injection infrared diode lasers which have been demonstrated recently are considered. Finally, additional developments and the future challenges in HgCdTe MBE technology are discussed.
MBE Regrowth Over a Selectively Undercut GaAs Masking Layer
Authors: Hansing C.C. , Deng H. , Reifsnider J.M. , Deppe D.G. , Streetman B.G. 
Published: April 2011

ABSTRACTWe describe the use of molecular beam epitaxy (MBE) for regrowth over a photolithographically defined GaAs shadow mask to fabricate a buried etched void surrounding a vertical-cavity surface-emitting laser (VCSEL). The initial MBE growth consists of a GaAs etch stop layer, followed by an Al0.67Gao.33As spacer layer, and then a GaAs capping layer. After the initial growth, various diameter openings ranging from 2 to10 gtm are photolithographically defined in a photoresist layer, and the top GaAs layer is selectively etched. The exposed LTAlGaAs layer is next selectively etched with the etch time adjusted to undercut the top GaAs layer to create a shadow mask. An MBE regrowthis then performed which consists of alternating layers of GaAs and AlAs. Scanning electron microscopy, surface profiling, and optical microscopy are used to characterize the regrowth.We have used this shadow masking technique to realize a buried etched void surrounding the optically active part of a VCSEL. A continuous wave room temperature lasing thresholdof 0.47 mA for a 4 [tm device has been achieved, which to our knowledge is the lowest continuous wave room temperature threshold yet reported for a VCSEL.
Texture Development in Thin Nickel Oxide Films
Authors: Czerwinski F. , Szpunar J.A. 
Published: April 2011

ABSTRACTX-ray diffraction was used to study the influence of ultra-fine dispersions of CeO2 on the texture development and epitaxial relationships in oxide films, formed at high temperatures. The substrate orientation exerted the essential effect on microstructure and growth rate of oxide films on both pure as well as coated nickel. NiO grown on (100)Ni was polycrystalline with grains randomly oriented. Applying of CeO2 resulted in a marked decrease of the oxide growth rate without significant changes in the texture. The NiO formed on pure (111)Ni exhibited strong (111) texture. During initial stages of oxidation the presence of CeO2 caused the nucleation of randomly oriented oxide. However, the oxide developed during further exposure had the same character as that grown on pure (111)Ni face. X-ray measurements are compared with analysis conducted by TEM and electron microdiffraction. The role of chemically active element in inhibition of diffusion processes during the growth of oxides on both crystal faces is discussed.
Investigating the Role of Grain Boundaries in Interface Reactions
Authors: d'Heurle FranÇois M , Gas Patrick , Philibert Jean 
Published: April 2011

ABSTRACTThe paper is built around a nonexhaustive review of the literature on the role of grain boundaries in reactive phase formation. Examples are chosen to illustrate these effects in silicide and oxide growths, and later on in metal-metal interactions. A short section deals with the effect of grain boundaries and grain boundary adsorption of impurities on the kinetics of growth and on the morphology of the growing layer. Some attempts at understanding the mechanisms of phase growth from the tracking of isotopes are briefly analyzed.
Grain Growth in Polycrystalline Thin Films
Authors: Thompson Carl V. 
Published: April 2011

ABSTRACTThe performance and reliability of polycrystalline films are strongly affected by the average grain size and the distribution of grain sizes and orientations. These are often controlled through grain growth phenomena which occur during film formation and during subsequent processing. Abnormal rather than normal grain growth is most common in thin films, and leads to an evolution in the distribution of grain orientations as well as grain sizes, often leading to uniform or restricted crystallographic orientations or textures. Surface and interface energy minimization and strain energy minimization can lead to development of different textures, depending on which is dominant. The final texture resulting from grain growth depends on the film thickness, the deposition temperature, the grain growth temperature, the thermal expansion coefficients of the film and substrate, and the mechanical properties of the film, as well as other factors.
Epitaxy and Crystallographic Texture of Thin Films for Magnetic Recording
Authors: Laughlin David E. , Feng Y.C. , Lee Li-Lien , Wong B. 
Published: April 2011

ABSTRACTThin films for magnetic recording are usually deposited on metallic Cr underlayers to control their crystallographic texture and other microstructural features such as grain size and crystal perfection. In this paper, the mechanisms involved in the production of thin films (both underlayers and magnetic layers) with specific crystallographic textures is reviewed and discussed. We first present an overview of a model for the development of the initial crystallographic texture of films grown on amorphous substrates. The textures that various films develop during growth are next discussed followed by a review of the role of epitaxy of Co-alloy films on Cr with underlayers and interlayers. The control of grain size of the magnetic film is also discussed in light of the underlayer grain size. Finally, the role of epitaxy on crystalline perfection and subgrain structure is discussed.
Preparation of PZT Thin Films by ECR PECVD
Authors: Kim J. W. , Kim S. T. , Chung S. W. , Shin J. S. , No K. S. , Wee D. M. , Lee W. J. 
Published: April 2011

ABSTRACTLead zirconate titanite (PZT) thin films have been prepared on Pt/Ti/SiO2/Si and Pt/Ta/Si2/Si substrates by electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR PECVD) at low temperatures using metal-organic (MO) sources. One of the advantages of this method is the easy control of the cation concentrations in the PZT films through the adjustment of the flow rates of each MO sources. The film compositional ratio Ti/Zr was found to be linearly proportional to the flow rate ratio of the input Ti and Zr MO sources. The Pb/(Zr+Ti) ratio was not so much affected by the Ti source flow rate but was inversely proportional to the Zr source flow rate. Pb concentration in the deposited PZT films increased with increasing Ti source flow rate and with decreasing substrate temperature. Perovskite single phase PZT films were successfully fabricated at low temperatures below 500 °C. The perovskite structure was obtained when the Pb/(Zr+Ti) ratio in the deposited film was close to 1.
Internal Stress Change of Phosphorus-Doped Amorphous Silicon Thin Films During Crystallization
Authors: Miura Hideo , Nishimura Asao 
Published: April 2011

ABSTRACTInternal stress change of phosphorus-doped silicon thin films during crystallization is measured by detecting substrate curvature change using a scanning laser microscope. The films are deposited in an amorphous phase by chemical vapor deposition using Si2H6 gas. The deposited films have compressive stress of about 200 MPa. The internal stress changes significantly to a tensile stress of about 800 MPa at about 600 °C due to shrinkage of the films during crystallization. The high tensile stress can be relaxed by annealing above 800 °C. The phosphorus doping changes the crystallization process of the films and their final residual stress.
Effects of Crystallographic Orientation on Film Morphological Evolution
Authors: Sanchez John E. 
Published: April 2011

ABSTRACTThe factors that determine the thermal strains, stresses and plastic yielding during the annealing of deposited Al thin films on Si substrates are reviewed. The effect of film texture orientation on dislocation glide is described and is shown to lead to variations in film strain energy with texture orientation. The strain energy difference between adjacent grains of different texture is proposed to account for several morphological changes during film annealing. If grain boundaries are mobile (i.e., with small initial diameter) film stresses and strain energies may induce the (secondary) growth of weakly oriented (110), (112), etc., grains at the expense of the normally favored (111) strongly oriented grains. If grain boundaries are stagnant, the strain energy differences between grains may induce the hillock growth of weakly oriented (110) grains in order to reduce film compressive stresses, and may also induce the depletion “sinking” of strongly oriented (111) grains in order to relieve film tensile stresses. This model generally accounts for these experimental findings of others.
Mechanical Behavior of Single Crystal A1 (111) and Bicrystal Al (110) Films on Silicon Substrates
Authors: Besser Paul R. , Sanchez John E. , Brennan S. , Bravman John C. , Takaoka G. , Yamada I. 
Published: April 2011

ABSTRACTSingle crystal Al (111) films and bicrystal Al (110) films have been deposited on bare Si (111) and (100) wafers using ion-cluster beam deposition. The stress in the films was determined using X-rays diffraction as the films were thermally cycled from room temperature to 400C. The (111) film exhibited nearly ideal elastic behavior as the stress was essentially linear with temperature. The (110) Al film yielded in compression at a lower temperature and stress than the (111) film and exhibited broad hillocks not found in the Al (111) film. During the second thermal cycle, both films behaved in a nearly ideal elastic fashion. Measurement of the strain relaxation in the films during the second thermal cycle showed that the (110) film relaxed significantly while the (111) did not relax.
Crystallization of Hydrogenated Amorphous Silicon Thick Films on Molybdenum Substrates
Authors: Sridhar Nagarajan , Chung D. D. L. , Anderson W. A. 
Published: April 2011

ABSTRACTCrystallization of hydrogenated amorphous silicon thick films deposited by dc glow discharge on molybdenum substrates was studied by Raman scattering and x-ray diffraction. Investigation was made as a function of amorphous silicon film deposition temperature. On heating the films at a rate of 5 °C/min to 650 °C for various times, it was observed that the film deposited at 300 °C started crystallization faster than the film deposited at 150 °C. The degree of cirystallinity increased with increasing annealing time for all the films. However, at all annealing times, the degree of crystallinity for the annealed film deposited at 150 °C was higher than that of the annealed film deposited at 300 °C, indicating that the crystallization growth rate was higher for the film deposited at a lower temperature. These results were consistent with the dark conductivity measurements. The film deposited at 150 °C showed a photoresponse which increased with increasing annealing time whereas no photoresponse was observed for the film deposited at 300 °C. This was probably due to the degree of crystallinity and grain size being much larger for the film deposited at 150 °C than the film deposited at 300 °C.
XRD Texture and Morphology Analysis of Polycrystalline LPCVD Germanium-Silicon
Authors: Salm Cora , Klappe Jos G.E. , Holleman Jisk , Bart Rem Jan , Woerlee Pierre H. 
Published: April 2011

ABSTRACTThe morphology and texture of polycrystalline LPCVD GexSi1-x alloys have been studied for various deposition temperatures and for x = 0, x = 1 and x ≈ 0.3. The transition temperature of amorphous to polycrystalline growth is much lower for Ge and GexSi1-x than for Si. Just above this transition temperature, we observed a (220) orientation for all polycrystaline layers grown. At elevated temperatures a change to the (004) orientation for poly-GexSi1-x and (331) for poly-Si and poly-Ge is noted.