Epitaxial Growth Of Gallium Arsenide Research Articles

Orientation-dependent epitaxial growth of GaAs by current-controlled liquid phase epitaxy

The orientation dependence of the selective epitaxial growth of Gallium Arsenide (GaAs) has been investigated to achieve a thick epitaxial layer for application to X-ray detectors. Selective epitaxial growth was carried out on patterned GaAs with [0 1 1], [0 1 2], [0 1 0], [0 1 −2], [0 1 −1] and their equivalent seed orientations by current-controlled liquid phase epitaxy (CCLPE). SiO 2 was used as a mask layer to fabricate the various seed orientations on the Si-doped GaAs (1 0 0) substrate and various growth periods and current densities were considered. Solute transport in the solution was enhanced by the electromigration of solute by an applied DC electric current, which caused an incremental growth in vertical and lateral directions in all orientations. The highest vertical thickness of 268 μm in the [0 1 −1] orientation and the largest lateral growth of 318 μm in the [0 1 2] orientation were achieved at 7.5 A cm −2 current density for 6 h. The seed aligned in the [0 1 2] orientation was favorable for high lateral growth of GaAs. The [0 1 1], [0 1 0] and [0 1 −2] seed orientations were suitable for application in a GaAs X-ray detector.

Thermo-Flow Structure and Epitaxial Uniformity in Large-Scale Metalorganic Chemical Vapor Deposition Reactors with Rotating Susceptor and Inlet Flow Control

The transport phenomena in large-scale metalorganic chemical vapor deposition (MOCVD) reactors with a rotating susceptor are investigated by numerical simulation of thin-film epitaxial growth of gallium arsenide. We are mainly concerned with the thermo-flow structure, its influence on epitaxial growth rate, and the means of improving epilayer flatness. The effects of susceptor rotation and thermo-flow conditions on gas flow, temperature and concentration fields are studied. The present results show the flow structure and transport characteristics in various flow regimes. A parameter map and the associated correlations of boundary curves of the flow-mode transition are proposed. It is demonstrated that the epilayer flatness can be tuned either by properly controlling the vortex strength in a rotation-dominated flow regime and/or by employing an inlet flow control technique proposed in the present work.

Do gas phase adducts form during metalorganic vapour phase epitaxial growth of gallium arsenide?

The new primary arsine hex-5-enylarsine (hexAsH 2) has been synthesized and decomposed in the liquid and gas phases in the presence and absence of trimethylgallium. From the gas phase decomposition by itself in vacuo the main product is hex-1-ene, although smaller amounts of cyclic C 6 products and of conjugated hexadienes are observed. Under growth conditions (1 atm of H 2 > 350°C) the hex-1-ene formed fragments completely because of hexAsH 2 first gives the adduct [Me 3Ga·AshexH 2] but this sequentially loses two moles of methane before giving GaAs, methylenecyclopentane and methane, showing that methylenecyclopentane will necessarily be a product if adduct formation occurs. In the gas phase in vacuo the major C 6 product from Me 3Ga and hexAsH 2 is hex-1-ene although there is a small increase in the proportion of methylenecyclopentane and cyclohexene, suggesting that two pathways, one involving adducts (minor) and the other not, operate. In hydrogen, the major C 6 products are methylenecyclopentane and cyclohexane confirming that adducts can be important, but, since hex-1-ene fragments under these conditions it is not possible to quantify the extent of adduct formation. These results are analysed in terms of the calculated equilibrium constant for adduct formation together with the residence time in the cold zone of the reactor and the probability of bimolecular reactions occurring. It is concluded that comparative studies under a variety of different conditions are essential for a full understanding of the processes occurring during growth.

Epitaxial growth of gallium arsenide prepared by low-pressure metal-organic chemical vapour deposition at low temperatures

The low-pressure metal-organic chemical vapour deposition (LPMOCVD) technique has been investigated previously as a growth method for compound semiconductors, offering the possibility of selective epitaxy and the potential advantage of better controllability for changing the doping level and the alloy composition. Low-temperature growth is also desirable to reduce the carbon incorporation generated by the decomposition of the organic radicals. In this article we report for the first time the epitaxial growth of gallium arsenide (GaAs) by LPMOCVD at temperatures as low as 510 °C. The vertical reactor that was developed by the authors employs conventional precursors such as trimethylgallium and arsine. By carefully choosing the growth parameters, we were able to grow high-quality GaAs epilayers with good surface morphology at temperatures as low as 510 °C. The carbon incorporation is shown to decrease with decreasing growth temperature without deterioration of the film quality. By carefully controlling the purity of the sources and the gas flow dynamics, we reduced the deep level impurity concentration and obtained reproducible n-type material with residual net donor concentration of 4.4 × 1014 cm−3 and mobility of 92 000 cm2 V−1 s−1 at 77 K.

Modeling the epitaxial growth of gallium arsenide

Journal of Electronics ManufacturingVol. 01, No. 01, pp. 51-56 (1991) PapersNo AccessModeling the epitaxial growth of gallium arsenideA.K. MACPHERSON, D. BEHBOUDI, J.C.M. HWANG, and G. MICEKA.K. MACPHERSONPackard Laboratory 19, Lehigh University, Bethlehem, PA 18015, USA Search for more papers by this author , D. BEHBOUDIPackard Laboratory 19, Lehigh University, Bethlehem, PA 18015, USA Search for more papers by this author , J.C.M. HWANGPackard Laboratory 19, Lehigh University, Bethlehem, PA 18015, USA Search for more papers by this author , and G. MICEKPackard Laboratory 19, Lehigh University, Bethlehem, PA 18015, USA Search for more papers by this author https://doi.org/10.1142/S0960313191000072Cited by:1 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractA molecular dynamics model of the epitaxial growth of gallium arsenide has been written. The results from the model will be used to obtain parametric growth data including layer thickness and doping concentration. Initially it was necessary to check the potential, which was developed for bulk gallium arsenide, for its applicability to surface growth. The resultant continuum model, when integrated with Stanford University’s SUPREM 3.5 code, will simulate gallium arsenide processing based on epitaxial material.Keywords:Gallium arsenidemolecule dynamicsepitaxial growth FiguresReferencesRelatedDetailsCited By 1Some aspects of the physics of man-made semiconductor heterosystems: superlattice electronic structure and related topicsPierre Masri1 Nov 1993 | Surface Science Reports, Vol. 19, No. 1-2 Recommended Vol. 01, No. 01 Metrics History Received 1 May 1991 Accepted 1 June 1991 KeywordsGallium arsenidemolecule dynamicsepitaxial growthPDF download

Selective-area epitaxial growth of gallium arsenide on silicon substrates patterned using a scanning tunneling microscope operating in air

Selective-area epitaxial growth of gallium arsenide on n-Si(100) substrates is reported, where the oxide (SiOx) mask consists of 1–2 monolayer-thick features patterned onto a silicon substrate using a scanning tunneling microscope (STM) operating in air. The technique for generating the STM patterns on hydrogen-passivated silicon was reported recently [J. A. Dagata, J. Schneir, H. H. Harary, C. J. Evans, M. T. Postek, and J. Bennett, Appl. Phys. Lett. 56, 2001 (1990)]. The GaAs epilayer was grown by migration-enhanced epitaxy at 580 °C and its morphology was investigated by scanning electron microscopy. The chemical selectivity of the STM-patterned regions was verified by imaging time-of-flight secondary-ion mass spectrometry. The implications of these results for the development of a unique, STM-based nanostructure fabrication technology are discussed.

Ultraviolet light-driven epitaxial growth of gallium arsenide at reduced substrate temperatures

We report on the photodeposition of gallium arsenide on gallium arsenide and silicon at low substrate temperatures utilizing ultraviolet radiation. A 1000 W Hg-Xe arc lamp serves as the light source with triethylgallium and arsine serving as the reactants. In this study, single crystal gallium arsenide thin films are obtained at substrate temperatures of approximately 357°. The electrical, chemical and structural properties of the photodeposited films are presented and the mechanisms involved in the deposition process are discussed. It is found that both photolytic and pyrolytic mechanisms are involved in the deposition process for the experimental conditions considered and that the desorption of excess arsenic is important in the low temperature growth of GaAs using photochemical means.

Selective epitaxial growth of gallium arsenide by molecular beam epitaxy

GaAs was selectively grown on GaAs substrates patterned with SiO2 by conventional molecular beam epitaxy (MBE). No growth was found on SiO2, except for small GaAs particles, when the substrate temperature was above 700 °C under 1.2×10−5 Torr arsenic pressure. With the increase in the substrate temperature, the selectivity was better while the growth rate decreased. At 775 °C, no growth occurred, even on GaAs. Selective epitaxial growth of GaAs by MBE is promising for application to device fabrications.

Liquid phase epitaxial growth of gallium arsenide on an etched substrate

A method is described for etching the surface of GaAs substrates with a Ga solution in situ immediately prior to epitaxial layer growth from the liquid phase. Layers grown by this procedure show excellent surface morphologies and electrical properties ( μ∼5100 cm 2 v-sec at 300°K for n∼ 7.8×10 16 cm 3 ). Advantages of the method and its applicability to epitaxial growth of other III-V compounds are discussed.

Lead as a solvent for gallium arsenide

The solubility of gallium arsenide in liquid lead, in the temperature range used for the epitaxial growth of gallium arsenide, is similar to the solubility in liquid gallium. However the mode of dissociation of the solute appears to be different in the two solvents. Epitaxial layers grown from solution in lead have free electron concentrations of the order of 10 18 cm −3.

A new rotating-boat technique for liquid phase epitaxial growth of gallium arsenide

A new technique has been developed to avoid constitutional supercooling in the growth of gallium arsenide by liquid phase epitaxy from an unconfined Ga-rich solution. This technique utilises a graphite boat that permits the growth solution to be initially saturated with GaAs at a temperature significantly higher than the substrate temperature. The boat is rotated to bring the solution into contact with the substrate, and rotated again to decant the solution after the growth is completed. If the initial temperature difference between the solution and the substrate is high enough, constitutional supercooling does not occur, and this procedure yields epitaxial layers with smooth surfaces free of cellular structure.

Study of the diffusion of gallium and arsenic into germanium during the epitaxial growth of gallium arsenide on the latter

The distribution of gallium and arsenic atomc (as well as the carrier distribution) in the diffusion layer of a germanium surface subjected to the epitaxial growth of gallium arsenide is examined. It is found that the nature of the p-n junction formed in the germanium is determined by the diffusion of gallium as well as arsenic; gallium exhibits an anomalously high rate of diffusion in germanium.

Epitaxial Growth of Gallium Arsenide on Germanium Substrates: III . Deposition on High Index Planes and on Curved Surfaces

When depositing gallium arsenide on low index planes of germanium from the vapor phase by halogen transport, stacking faults are readily formed. Films free of these faults were obtained when planes that were at an angle of a few degrees with a {111} face or curved surfaces were used as substrates. It is suggested that fast propagation of steps along the surface caused the formation of new stacking faults parallel to the existing ones, thereby completing loops and preventing the propagation of the faults. The rate of growth was much faster on curved surfaces than over the {111} planes.

Epitaxial Growth of Gallium Arsenide on Germanium Substrates: II . Deterioration of the {111} Surface of Germanium at 570°–850°C

It has been shown that on heating germanium crystals in hydrogen or in vacuum at temperatures 570°–850°C, deterioration of the 111 planes takes place. Temperature gradients and adsorbed impurities are the probable causes of the deterioration. Impurities cause the formation of etch‐ and growth‐structures which in their absence would be unstable.

Epitaxial Growth of Gallium Arsenide on Germanium Substrates: I . The Relationship between Fault Formation in Gallium Arsenide Films and the Surface of Their Germanium Substrate

Morphological and etching studies on films of gallium arsenide deposited on germanium substrates have revealed twin planes, grains, and stacking faults. The evidence suggests that these defects are related to the faceting of the substrate and to the presence of oxide films.