Showing papers on "Epitaxy published in 1986"
TL;DR: In this article, the growth condition dependence of crystalline quality is also studied, and the narrowest x-ray rocking curve from the (0006) plane is 2.70' and from the 2024 plane is 1.86' on sapphire substrates.
Abstract: Atmospheric pressure metalorganic vapor phase epitaxial growth and characterization of high quality GaN on sapphire (0001) substrates are reported. Using AlN buffer layers, GaN thin films with optically flat surfaces free from cracks are successfully grown. The narrowest x‐ray rocking curve from the (0006) plane is 2.70’ and from the (2024) plane is 1.86’. Photoluminescence spectra show strong near band edge emission. The growth condition dependence of crystalline quality is also studied.
2,035 citations
TL;DR: In this article, the use of a novel chemical vapor deposition technique, ultrahigh vacuum/chemical vapor deposition, to deposit homoepitaxial silicon layers of high crystalline perfection at low temperatures (T≥750 °C) was successfully demonstrated.
Abstract: We have successfully demonstrated the use of a novel chemical vapor deposition technique, ultrahigh vacuum/chemical vapor deposition, to deposit homoepitaxial silicon layers of high crystalline perfection at low temperatures (T≥750 °C). Rutherford backscattering and transmission electron microscopy showed the transition to epitaxial silicon growth took place in the range 700–750 °C, and secondary ion mass spectrometry showed typical oxygen and carbon levels to be near the detection limits of the technique 1016–1017 cm−3. In addition, abrupt dopant transitions have been demonstrated, with B levels dropping four orders of magnitude, 1019–1015 B/cm3, in the first 1000 angstroms of an intrinsic epilayer.
482 citations
TL;DR: In this article, the phase transition of the PbTiO3 thin film was studied by high-temperature x-ray diffraction, and it was found that the c-axis of the tetragonal phase was parallel to the substrate just below Tc and the c−axis becomes perpendicular to a substrate with lowering of temperature.
Abstract: Highly c‐axis oriented and epitaxial PbTiO3 thin films were grown on MgO single crystals and epitaxial Pt film substrates by the rf‐magnetron sputtering method. The films with a 98% c‐axis orientation rate were obtained under low deposition rate (<20 A/min) and low gas pressure (∼1 Pa) using a PbO‐rich target. Phase transition of the PbTiO3 thin film was studied by high‐temperature x‐ray diffraction. It was found that the c‐axis of the tetragonal phase was parallel to the substrate just below Tc and the c‐axis becomes perpendicular to the substrate with lowering of temperature. These films show high resistivity (∼1010/Ω cm). It was found that significant pyroelectric currents are detected on all specimens without poling treatment. The polarization directions of the films are the same in all specimens. One of these films had a low relative dielectric constant of 97 and a high pyroelectric coefficient of 2.5×10−8 C/cm2 K without poling treatment. These films will be suitable for applications such as pyroelectric infrared detector and piezoelectric transducer.
397 citations
[...]
TL;DR: Atomic layer epitaxy (ALE) as mentioned in this paper is a self-regulatory process which produces one complete molecular layer of a compound per operational cycle, with a greater thickness being obtained by repeated cycling.
Abstract: Atomic layer epitaxy (ALE) is not so much a new technique for the preparation of thin films as a novel modification to existing methods of vapor‐phase epitaxy, whether physical [e.g., evaporation, at one limit molecular‐beam epitaxy (MBE)] or chemical [e.g., chloride epitaxy or metalorganic chemical vapor deposition (MOCVD)]. It is a self‐regulatory process which, in its simplest form, produces one complete molecular layer of a compound per operational cycle, with a greater thickness being obtained by repeated cycling. There is no growth rate in ALE as in other crystal growth processes. So far ALE has been applied to rather few materials, but, in principle, it could have a quite general application. It has been used to prepare single‐crystal overlayers of CdTe, (Cd,Mn)Te, GaAs and AlAs, a number of polycrystalline films and highly efficient electroluminescent thin‐film displays based on ZnS:Mn. It could also offer particular advantages for the preparation of ultrathin films of precisely controlled thickne...
263 citations
TL;DR: In this paper, electron diffraction measurements on (100) GaAs1−xSbx layers with x≊0.5 grown by organometallic vapor phase epitaxy indicate that ordered phases are formed during growth.
Abstract: Electron diffraction measurements on (100) GaAs1−xSbx layers with x≊0.5 grown by organometallic vapor phase epitaxy indicate that ordered phases are formed during growth. Two ordered phases are observed. The simple, tetragonal AuCu‐I type phase consists of alternating {100} oriented GaAs and GaSb layers. Only the two variants with the tetragonal c axes perpendicular to the growth direction are observed. At least two variants are observed for the chalcopyrite E11 structure with alternating {210} oriented GaAs and GaSb layers.
181 citations
TL;DR: In this article, the atomic layer epitaxy of zinc chalcogenide single crystalline films on a (001) GaAs substrate is studied, and the average thickness per one cycle of opening and closing the shutters of the constituent elements corresponds to one monolayer thickness.
Abstract: Atomic layer epitaxy of zinc chalcogenide single crystalline films on a (001) GaAs substrate is studied. It is observed that the average thickness per one cycle of opening and closing the shutters of the constituent elements corresponds to one monolayer thickness. The initial and successive stages of the epitaxy are investigated by reflection high‐energy electron diffraction. Three‐dimensional growth mechanism dominates at the initial stage of the heteroepitaxy, while pseudo‐two‐dimensional growth mechanism dominates after the deposition of more than 1000 monolayers. However, the growth of ZnSe on ZnTe and vice versa is dominated by the two‐dimensional growth mechanism.
162 citations
TL;DR: In this article, the epitaxial growth of GaAs by means of molecular beams of Ga(CH3)3 (TMG) or Ga(C2H5)3(TEG) and AsH3.
158 citations
TL;DR: In this article, an intentionally doped gallium antimonide has been grown by molecular beam epitaxy on gallium arsenide and gallium anti-antimonide, and a strong correlation has been found between the quality of the layers and the degree of excess antimony flux; the best material was obtained with the minimum antimony stable growth at a particular substrate temperature.
Abstract: Unintentionally doped gallium antimonide has been grown by molecular‐beam epitaxy on gallium arsenide and gallium antimonide. Substrate temperatures in the range 480 to 620 °C and antimony to gallium flux ratios from 0.65 : 1 to 6.5 : 1 have been investigated. The deposition conditions have been related to growth morphology and to the electrical and optical properties of the epitaxial films. A strong correlation has been found between the quality of the layers and the degree of excess antimony flux; the best material in terms of both optical and electrical properties was obtained with the minimum antimony stable growth at a particular substrate temperature. All the material exhibited residual p‐type behavior. The lowest hole concentration achieved was 7.8×1015 cm−3 with a corresponding room‐temperature mobility of 950 cm2/V s. The narrowest PL (photoluminescence) features observed were peaks associated with bound exciton transitions with half‐widths of 2–3 meV.
145 citations
TL;DR: In this paper, a comprehensive study of selective epitaxial deposition of GaAs on partly masked GaAs substrates using TMG or TEG and AsH3 in H2 (MOCVD) at 5X102 to 105 Pa total pressure, and in an ultra high vacuum apparatus without carrier gas (MOMBE).
129 citations
Patent•
13 Jun 1986TL;DR: In this paper, the integration of Si MOSFETs and gallium arsenide MESFET on a silicon substrate is described, except for contact openings and final metallization.
Abstract: Monolithic integration of Si MOSFETs and gallium arsenide MESFETs on a silicon substrate is described herein. Except for contact openings and final metallization, the Si MOSFETs are first fabricated on selected areas of a silicon wafer. CVD or sputtering is employed to cover the wafer with successive layers of SiO 2 and Si 3 N 4 to protect the MOSFET structure during gallium arsenide epitaxy and subsequent MESFET processing. Gallium arsenide layers are then grown by MBE or MOCVD or VPE over the entire wafer. The gallium arsenide grown on the bare silicon is single crystal material while that on the nitride is polycrystalline. The polycrystalline gallium arsenide is etched away and MESFETs are fabricated in the single crystal regions by conventional processes. Next, the contact openings for the Si MOSFETs are etched through the Si 3 N 4 /SiO 2 layers and final metallization is performed to complete the MOSFET fabrication. In an alternative embodiment, Si MOSFETs and aluminum gallium arsenide double heterostructure LEDs are formed in a similar manner.
122 citations
TL;DR: In this article, photo assisted molecular beam epitaxy (MBE) was applied to CdTe films with indium and an argon ion laser was used as an illumination source.
Abstract: We report details of the successful controlled substitutional doping of CdTe films with indium. These n‐type films were prepared using a new technique, photoassisted molecular beam epitaxy, in which the substrate is illuminated during the deposition process. In the present work, an argon ion laser was used as an illumination source. The incident light was found to produce immediate and significant changes in the electrical properties of the films. In particular, highly activated n‐type CdTe:In layers resulted.
TL;DR: Growth of GaAs by repeated deposition of single atomic layers using the switched laser metalorganic vapor phase epitaxy technique is reported in this paper, where a growth model for stepwise monolayer epitaxy is proposed which suggests that photocatalytic decomposition of TMG occurs only at surface As atoms and not at Ga atoms.
Abstract: Growth of GaAs by repeated deposition of single atomic layers using the switched laser metalorganic vapor phase epitaxy technique is reported. Suspension of Ga deposition at 100% coverage is an essential part of the growth mechanism for stepwise epitaxy—the ideal atomic layer epitaxy. This is achieved by suppressing pyrolytic decomposition and favoring photocatalytic decomposition of trimethylgallium (TMG). A growth model for stepwise monolayer epitaxy is proposed which suggests that photocatalytic decomposition of TMG occurs only at surface As atoms and not at Ga atoms.
TL;DR: In this paper, a theory of epitaxial growth appropriate to overlayer materials that can adopt a bulk metastable crystal structure with a lattice constant significantly different from that of the stable ground state structure was presented.
Abstract: We present a theory of epitaxial growth appropriate to overlayer materials that can adopt a bulk metastable crystal structure with a lattice constant significantly different from that of the stable ground state structure, as is common for metal epitaxy. This requires a generalization of the traditional Frank and van der Merwe theory to a regime where the overlayer responds nonlinearly to the large shear stress exerted by the substrate. New results are obtained for the commensurate-incommensurate transition (for thin layers) and the coherent-incoherent transition (for thick layers) that are presented in the form of a structural phase diagram as a function of epitaxial misfit and overlayer thickness. We predict that a crystallographic analog to spinodal decomposition can occur in certain ranges of large misfit. The nature of substrate-stabilized metastable epitaxy is clarified and a further analogy to martensitic phase transitions is exploided to predict the microstructure that must accompany the transformation of a metastable overlayer to the ground state structure for sufficiently thick overlayers Presentation d'une theorie de la croissance epitaxiale adaptee aux materiaux de surcouche pouvant adopter une structure cristallographique metastable volumique avec un parametre cristallin assez different de celui de la structure stable de l'etat fondamental
TL;DR: In this article, the effect of the tilting of substrate surfaces on the formation of defects was investigated with a 1mV ultrahigh vacuum, high voltage electron microscope, and two types of misfit dislocations, one with Burgers vectors parallel to the interface and the other inclined from the interface by 45°, were found in the epitaxial interface.
Abstract: Recent studies have shown that high quality GaAs films can be grown by molecular beam epitaxy on Si substrates whose surfaces are slightly tilted from the (100) plane. In order to investigate the effect of the tilting of substrate surfaces on the formation of defects, the atomic structure in the GaAs/Si epitaxial interface has been studied with a 1‐MV ultrahigh vacuum, high voltage electron microscope. Two types of misfit dislocations, one with Burgers vectors parallel to the interface and the other with Burgers vectors inclined from the interface by 45°, were found in the epitaxial interface. The observation of two cross‐sectional samples perpendicular to each other has shown that the tilting of the substrate surface directly influences the formation of these two types of misfit dislocations. A possible mechanism of the reduction of threading dislocations by tilting the substrate surface is discussed based on these observations.
TL;DR: In this paper, a low temperature epitaxial silicon process with UHV/CVD is described, and the transition to high quality, low defect density material to occur between 750° and 800°C, and such films were found to be of high chemical purity.
Abstract: Fundamental equilibrium considerations derived from the system have been successfully employed in the design and operation of a novel low temperature epitaxial silicon process. Films have been deposited in the range, with all resulting material epitaxial. TEM studies showed the transition to high quality, low defect density material to occur between 750° and 800°C, and such films were found to be of high chemical purity as well. In addition, UHV/CVD is shown to be a high throughput multiwafer system, achieving good film uniformities in a high wafer packing density environment, attributable to operation in the low pressure limit of chemical kinetics.
TL;DR: In this paper, a dual-grown-chamber method for GaAs atomic layer epitaxy is demonstrated in hydride vapor phase epitaxy by a dualgrown chamber method where the GaAs substrate is alternatively exposed to GaCl and As4 gases by transferring the substrate between two chambers.
Abstract: GaAs atomic layer epitaxy is demonstrated in hydride vapor phase epitaxy by a dual-grown-chamber method. GaAs substrate is alternatively exposed to GaCl and As4 gases by transferring the substrate between two chambers. The growth rate was examined for differing growth conditions and was found to depend only on substrate transfer cycles. Furthermore, the present method can be applied to selective growth.
TL;DR: In this article, high-quality rare-earth (RE) single-crystal films of yttrium (Y) and gadolinium (Gd) were successfully grown with the metal molecular beam epitaxy technique on a bcc Nb singlecrystal film which serves as a buffer layer to the sapphire substrates.
Abstract: High‐quality rare‐earth (RE) single‐crystal films of yttrium (Y) and gadolinium (Gd) were successfully grown with the metal molecular beam epitaxy technique on a bcc Nb single‐crystal film which serves as a buffer layer to the sapphire substrates. With reflection high‐energy electron diffraction, the hcp RE (0001) was found to grow epitaxially on the (110) Nb in the Nishiyama–Wasserman orientation. The regrowth of Nb on this RE (0001) surface yielded the (110) orientation with 120° in‐plane domains. These epitaxial relationships suggest the possibility of fabricating an ultrathin, coherent crystalline superlattice in the Nb (110)/ RE (0001) system.
TL;DR: In this paper, the formation of the Fe/GaAs(001)-c(8\ifmmode\times\else\texttimes\fi{}2) interface was examined using high-energy-resolution x-ray photoelectron spectroscopy.
Abstract: We have combined high-angular-resolution Auger-electron diffraction, kinematical scattering calculations, low-energy-electron diffraction (done in a pulse-counting mode), and high-energy-resolution x-ray photoelectron spectroscopy to examine the formation of the Fe/GaAs(001)-c(8\ifmmode\times\else\texttimes\fi{}2) interface. We find that clusters of bcc Fe at least three atomic layers deep grow in registry with the substrate for coverages up to \ensuremath{\sim}4 monolayer equivalents. These clusters contain Ga and As atoms which have been liberated from the GaAs substrate. Above this coverage, the clusters coalesce into a continuous bcc Fe matrix with a lattice constant equal to half that of GaAs and with principal crystallographic axes parallel to those of the substrate. This epitaxial Fe overlayer contains Ga and As in solution in the bcc lattice with the impurity atoms occupying interstitial face-center sites. The concentration of Ga and As decreases with distance from the GaAs substrate. At the same time, we find clear evidence for surface segregation of As and enrichment of the near-surface region.
TL;DR: In this article, it was shown that the distribution relation of III-V alloys in MOVPE is determined mainly by the Gibbs free energy of formation of binary compounds and the input V/III ratio.
TL;DR: In this paper, a remote plasma-enhanced chemical-vapor deposition technique was used to extract epitaxial Ge films from Ge(111), Si(100), and GaAs(111)Ga face substrates.
Abstract: Epitaxial Ge films have been deposited at 300 °C using a remote plasma‐enhanced chemical‐vapor deposition technique where metastable He atoms flow downstream from the plasma region to dissociate GeH4 molecules into deposition precursor species. Ge epitaxy is demonstrated on Ge(111), Si(100), and GaAs(111)Ga face substrates. An in situ cleaning process that involves a moderate thermal bake at 300 °C and a hydrogen plasma etch of the native oxides is integral to the process. Reflection high‐energy electron diffraction is used to examine surface quality just prior to and after deposition. Uniform integral order diffraction streaks and fractional order reconstruction features observed from the Ge epilayers indicate that high quality Ge epitaxial layers can be grown using remote plasma‐enhanced chemical‐vapor deposition.
TL;DR: In this article, the growth of epitaxial CaF2 on Si substrates and subsequent overgrowth with Si or Ge has been studied, and the best quality crystal growth and surface morphology is obtained on (111) substrates, as t...
Abstract: The growth of an epitaxial insulator on a semiconductor substrate and its subsequent overgrowth with an epitaxial semiconductor has a number of important applications, including the construction of three‐dimensional devices, better isolation of devices in VLSI circuits, improved gate insulators, and optoelectronic devices. In addition, it presents a unique opportunity to study an insulator/semiconductor interface under controlled conditions. Many of the fluoride compounds are excellent insulators and can be grown epitaxially by MBE on many common semiconductors. Thus, epitaxial fluoride growth is being extensively studied at a number of laboratories. In our laboratory, the growth of epitaxial CaF2 on Si substrates and subsequent overgrowth with Si or Ge has been studied. While epitaxial growth of CaF2 (which has an fcc lattice structure as does Si) can be obtained on (100), (110), and (111) oriented Si substrates, the best quality crystal growth and surface morphology is obtained on (111) substrates, as t...
TL;DR: In this article, the formation of the GaAs/Ge interface produced by deposition of GaAs on Ge substrate thin films with (111 or (110) or (100) orientations has been investigated.
Abstract: Using an ultrahigh vacuum (UHV) scanning transmission electron microscope equipped with a molecular beam epitaxy chamber, the formation of the GaAs/Ge interface produced by deposition of GaAs on Ge substrate thin films with (111) or (110) or (100) orientations has been investigated. Three‐dimensional nucleation and growth of facetted GaAs epitaxial islands are characteristic of this interface. The formation energy and orientation of antiphase boundaries are obtained from the structure analysis of these ultrathin films.
TL;DR: In this article, the epitaxial layers of the compound semiconductors InSb and InAs 1− x Sb x have been prepared by metal organic chemical vapor deposition in a vertical, atmospheric pressure quartz reactor.
TL;DR: In this article, the quality of GaAs epitaxial layers prepared by molecular layer epitaxy (MLE) with and without UV light irradiation was studied and appears to be a promising method for preparing the GaAs thin layers with an atomic order accuracy.
Abstract: The quality of GaAs epitaxial layers prepared by molecular layer epitaxy (MLE) with and without UV light irradiation was studied and appears to be a promising method for preparing the GaAs thin layers with an atomic order accuracy. Namely, single layer‐by‐layer growth has been realized for GaAs using AsH3 and trimethyl (TMG), and triethyl (TEG), gallium. Substrate temperature of 500 °C for TMG and AsH3, and 300 °C for TEG and AsH3 fulfilled the conditions for monolayer growth, where the film growth thickness per cycle corresponding to 2.83 and 3.26 A for (100) and (111) B faces, respectively, are nearly saturated independently of the gas admittance quantity. Influences of photoirradiation on the film growth have been investigated by use of excimer lasers and Hg lamps. UV light irradiation improved the surface morphology and in certain instances also improved impurity concentrations. Conditioned photoirradiation—light beam synchronized with the time duration of AsH3 admittance, MO‐gas admittance, and evacu...
TL;DR: In this article, the effects of the offset angle of the substrate and its direction on the epitaxial layer were studied using spherical Si substrates, and the growth was carried out by a low pressure MOCVD system.
Abstract: In the growth of GaAs on Si, the effects of the offset angle of the substrate and its direction on the epitaxial layer were studied using spherical Si substrates. The growth was carried out by a low pressure MOCVD system. On the grown layer, milky lines were observed along the [010] and the [001] axis of the substrate. Except for the narrow regions along these milky lines, the grown layer showed a mirror-like surface with a single domain structure. The surface morphology and the etch pit density in the single domain GaAs layer were strongly affected by the offset direction as well as the offset angle of the substrate.
TL;DR: In this paper, the authors showed that a decrease in the ratio of the sum of the C and Si source gases to the H2 carrier gas changed the crystallization behavior from polycrystalline to monocrystalline.
Abstract: Epitaxial films of cubic β‐SiC(111) have been grown via chemical vapor deposition at 1683 K on (0001) substrates of hexagonal 6H α‐SiC. Optical microscopy of the surface indicated that a decrease in the ratio of the sum of the C and Si source gases to the H2 carrier gas changed the crystallization behavior from polycrystalline to monocrystalline. Cross‐sectional transmission electron microscopy showed almost no line or planar defects at the substrate/film interface and very few defects within the bulk of the film.
TL;DR: In this article, the authors have grown AlGaAs/GaAs heterostructures on (111) oriented GaAs substrates by molecular beam epitaxy and obtained materials with good optical and electrical properties, including mobility enhancement in two-dimensional electron and hole gases.
Abstract: We have grown AlGaAs/GaAs heterostructures on (111) oriented GaAs substrates by molecular beam epitaxy. Materials with good optical and electrical properties, including mobility enhancement in two‐dimensional electron and hole gases, have been obtained for the first time.
TL;DR: In this article, the intentional ρ-type doping of GaAs layers from molecular beams of arsine (AsH3) and mixtures of frimethyl gallium (TMG) and TEG was reported.
Abstract: We report on the intentional ρ-type doping of GaAs layers grown in an UHV system from molecular beams of arsine (AsH3) and mixtures of frimethyl gallium (TMG) and friethyl gallium (TEG). The entire doping range between 1014 cm-3 (growth from pure TEG) and 1020 cm-3 (growth from pure TMG) can be covered by using mixtures of TMG and TEG. As revealed by SIMS and photoluminescence (PL) carbon is the dominant acceptor in the layers. Comparison of the Hall mobility and of the PL spectra shows that the quality of our films equals that of the best LPE and MBE grown ρ-type GaAs layers.
TL;DR: In this paper, a new doping technique for phosphorous using a Zn3P2 source has been developed, based on an extensive study of the electrical properties of ZnSe doped with P, and it has been found that the doped P induces point defects in excess of the D atoms which lowers the electron concentration and the electron mobility much more than expected.
Abstract: A new doping technique for phosphorous using a Zn3P2 source has been developed. From an extensive study of the electrical properties of ZnSe doped with P, it has been found that the doped P induces point defects in excess of the doped P atoms which lowers the electron concentration and the electron mobility much more than expected. From an investigation of the low-temperature PL spectra, it was found that P forms a shallow acceptor with an activation energy of 80-92 meV in MBE-grown lightly P-doped ZnSe, and at the same time a deep acceptor with an activation energy of 0.6-0.7 eV in heavily P-doped ZnSe.
TL;DR: The first successful substitutional doping of CdTe films with antimony was reported in this article, in which the substrate is illuminated during the film deposition process, which produces favorable changes in the electrical properties of the cdTe:Sb films such that highly activated p-type layers resulted.
Abstract: We report the first successful substitutional doping of CdTe films with antimony. These p‐type epilayers were prepared using a new technique, photoassisted molecular beam epitaxy, in which the substrate is illuminated during the film deposition process. Illumination was found to produce immediate and favorable changes in the electrical properties of the CdTe:Sb films such that highly activated p‐type layers resulted. CdTe:Sb films grown under similar conditions, but in the absence of illumination, were found to be insulating.