Hitoshi Ogata

Gas source MBE growth of InP

We report the electrical and optical properties of InP epilayers grown by gas source molecular beam epitaxy (GSMBE) using trimethylindium (TMI) and phosphine (PH3) under various growth conditions. Reflection high-energy electron diffraction (RHEED) intensity oscillations during the growth of InP are also described. It is found that high quality epilayers are obtained at about 490°C, and at this temperature the RHEED intensity oscillations with periods of more than 700 are observed.

GaInAsP/InP lasers with etched mirrors by reactive ion etching using a mixture of ethane and hydrogen

A reactive ion etching method is applied to fabricate mirrors of 1.5 μm GaInAsP/InP mass transport lasers using a mixture of ethane and hydrogen as an etchant. Threshold currents as low as 35 mA are achieved for the 300‐μm‐long cavity lasers with one etched and one cleaved facet. The differential quantum efficiencies of the lasers with one dry etched facet and both dry etched facets are 13 and 9.5%, respectively.

Chemisorption of H2O on the Si(111) 7 × 7 surfaces

Abstract Chemisorption of H 2 O on the thermally cleaned Si(111) 7 × 7 surfaces has been studied by ultraviolet photoemission, energy loss and Auger electron spectroscopies. We provide direct experimental evidence that, at room temperature, the molecules non-dissociatively adsorb in a single state. It is also found that, with increasing annealing temperature up to ∼1500 K, the reaction processes proceed in three steps: molecular adsorption, dissociation and hydrogen desorption and oxygen desorption.

Observations on intensity oscillations in reflection high‐energy electron diffraction during gas source molecular beam epitaxy of InP

We report the first observation of reflection high‐energy electron diffraction intensity oscillations during the growth of InP using trimethylindium and phosphine in gas source molecular beam epitaxy (GSMBE). By optimizing the growth conditions, intensity oscillations more than 700 periods have been observed. The temperature and flux dependence of the oscillating behavior have been studied. Results indicate that the growth of InP by GSMBE is predominantly via a two‐dimensional layer‐by‐layer mode.

Effect of hydrogen molecules on growth rates of GaAs in gas source molecular beam epitaxy

We observed intensity oscillations of reflection high-energy electron diffraction during growth of GaAs using triethylgallium (TEG) and arsine (AsH3). The oscillation period increased with increasing AsH3 flow rate. We found that introduction of H2 or N2 during the growth also caused a decrease in the growth rate. The growth rate reduction is explained by assuming that transient residence of H2 or N2 molecules on the growing surface impedes adsorption of TEG molecules.

High-purity In0.53Ga0.47As layer grown by liquid phase epitaxy

Abstract High-purity InGaAs epitaxial layers with an area of 15 × 30 mm 2 were grown by using a conventional leak-tight liquid phase epitaxial growth system without any special treatments. A room temperature electron mobility as high as 12000 cm 2 V -1 s -1 and an electron concentration as low as (1−2) × 10 15 cm -3 were reproducibly achieved merely by baking the growth solution in hydrogen.

Diffusion of aluminum into silicon nitride films

Abstract Aluminum diffusion into silicon nitride films at temperatures in the range 450–530°C was studied by Auger electron spectroscopy in conjunction with depth profiling. The activation energy for the diffusion of aluminum and the diffusion coefficient were found to be 2.0±0.3 eV and (7.3±3.5) x 10 -3 cm 2 s -1 , respectively. The chemical effects in the KLL aluminum Auger spectra together with the compositional depth profiles suggest that the migration of aluminum is dominated by volume diffusion which involves the reaction of aluminum with oxygen.

Molecular beam epitaxy of GaAs x P 1 - x using low-energy P + ion beam

We describe the epitaxial growth of GaAsxP1-x (0 <x < 0.7) on GaAs(00l) substrates using mass-separated low-energy P+ ions, and Ga and As4 molecular beams. Epilayers have been obtained at growth temperatures(Tg) ranging from 300 to 650° C at P+ ion energies(Ep+) between 50 and 300 eV. We have investigated the growth rate as a function ofEp+, and the film composition as a function of the flux ratio of As4 to P+,Tg andEp+. The sticking coefficient of phosphorus is markedly enhanced by using P+ ion, compared with that of As4. As the flux ratio of As4 to P+ is increased from 0 to 8, the composition ratiox of GaAsxP1-xfilms varies from 0 to 0.5. The composition ratiox decreases slightly with increasingTg from 400 to 650° C, and increases with increasingEp+. Film surfaces are smooth atEp+ below 100 eV, and their morphology is degraded with increasing energy.

Molecular beam epitaxy of InP using low-energy P + ion beam

Abstract InP was grown on Fe-doped semi-insulating InP(100) substrates by a new technique in which phosporus was supplied as a mass-separated low-energy ion beam and indium as molecular beam. The electrical and optical properties of the films grown under various conditions are discussed. The epitaxial growth of InP occured at growth temperatures above 200°C, and high quality InP films were obtained with a P + ion energy of 100 eV. The unintentionaly doped epilayers were n-type. The room temperature carrier concentration and Hall mobility of an InP film growth at 480°C and with a P+ ion energy of 100 eV were 1.3×1016 cm-3 and 3100 cm2⧸V · s, respectively. The as-grown surfaces was smooth without any oval type defects.

Electrical and optical properties of silicon doped InP grown by gas source MBE

Abstract A detailed investigation was carried out on the characteristics of Si-doped InP grown by gas source MBE (GSMBE) using trimethylindium, phosphine and solid Si source. It has been found that the InP epitaxial layers grown by GSMBE have excellent qualities comparable to those grown by other epitaxial techniques. Good agreement was obtained between the Si equilibrium vapor pressure curve and the temperature dependence of the carrier concentration in the range from 6X10 15 to 6X10 18 cm -3 . The Burstein-Moss shift was observed in the photoluminescence spectra.