tatsuya ohori - Academia.edu (original) (raw)

Papers by tatsuya ohori

Fujitsu Scientific & Technical Journal, 1983

ITE Technical Report, 1996

PURPOSE:To form an integrated circuit, having little irregularity in characteristics, is formed o... more PURPOSE:To form an integrated circuit, having little irregularity in characteristics, is formed on the compound semiconductor layer to be grown on a silicon substrate by a method wherein the compound semiconductor layer, to be formed under a gate electrode, is formed by the same material as the gate electrode when a plurality of kinds of transistors are formed. CONSTITUTION:A GaAs layer 2, an AlGsAs layer 3, a bit-stop GaAs layer 11, the second dry etching stop AlGaAs layer 12, a GaAs layer (bit-stop layer) 4, the first dry etching stop AlGaAs layer 5 and a GaAs layer (cap layer) 6 are formed on a silicon substrate 1 in the above-mentioned order. The bit stop GaAs layer 11 works as an etching stop layer against ammonium wet etching. The GaAs layer 11, which works as an etching stopper layer, appears on the gate electrode part of an E-mode element. By having the above-mentioned structure, the generation of pit on the gate electrode part of the E-mode element can be eliminated.

Journal of Crystal Growth, 1995

APD (antiphase domain) free GaAs is grown by molecular beam epitaxy on an epitaxial (100)Si subst... more APD (antiphase domain) free GaAs is grown by molecular beam epitaxy on an epitaxial (100)Si substrate with an offset angle of 0.3 ° without conventional high-temperature pretreatment. Reflection high energy electron diffraction (RHEED) demonstrates the presence of a double-domain reconstruction structure on the 0.3 ° misoriented Si substrate after pretreatment at 400-600°C. However, the GaAs epitaxial layers grown on these substrates by the two-step method were APD free. KOH etching and double crystal X-ray diffraction (DCXD) show the crystalline quality of GaAs grown on the epitaxial Si substrate is comparable to that of GaAs grown on conventional Si substrates heat-treated at 900°C. The evaluation by atomic force microscopy (AFM) shows the surface flatness of GaAs layer grown on the 0.3°-misoriented epi-substrate is much more superior to that grown on the epi-substrate with 2 ° offset.

We measured photoluminescence (PL) spectra under an applied electric field along the hetero-inter... more We measured photoluminescence (PL) spectra under an applied electric field along the hetero-interface to study hot electron scattering mechanisms in HEMTS. The electron temperature obtained from the PL spectra, indicates hot electron scattering conditions. intensity is enhanced by introducing an undoped AlGaAs barrier layer on the substrate side, since holes are confined within the quantum well. s spectra are obtained for three types of AIGaAstGaAsIAIGaAs single quantum wells (sows) whose doping conditions differed. We also measured barrier layer PL spectra to observe the effect of real space transfer (RST). electrons observed when RST occurred. An undoped AlGaAs barrier layer is inserted into the HEMT'S channel layer. PL We propose an energy cooling model to explain the anomalous cooling of hot

Journal of Crystal Growth, 1991

We demonstrate highly effective Si planar doping of GaAs hy atmospheric-pressure rnetalorganic va... more We demonstrate highly effective Si planar doping of GaAs hy atmospheric-pressure rnetalorganic vapor phase epitaxs MOVPE) using tertiaryhutylarsine (tBAs) as an alternative arsenic source. The Si incorporation coefficient using t BAs is always higher than that using arsine. The dependence of the Si incorporation coefficient on the group-V precu Nor flow rate and the gas flow velocity differs greatls between group-V precursors. this indicates that the gas phase reactions between group-V and dopaUt source dominate the Si doping pro~es~. regardless of group-Ill precursor. We applied a kinetic am ulation to the pyrolvsis (ii group-V precursors and confirmed that a large amount 01 AsH exists in the gas phase when using tIJAs. We propose that the reactions between As species radicals and silane occur, producing silylarsine (II AsSiI-I) and that si lvlarsinc is abundant fbr t I3As. Silvlarsine rather than Sill should he the most significant product contributing to the Si doping reactions.

Japanese Journal of Applied Physics, 1991

Journal of Crystal Growth, 1988

Uniform and abrupt Si-doped lnGaP/GaAs selectively doped heterostructures are grown by atmospheri... more Uniform and abrupt Si-doped lnGaP/GaAs selectively doped heterostructures are grown by atmospheric-pressure metalorganic chemical vapor deposition, and the feasibility of the material system for HEMT ICs is demonstrated for the first time. The uniformities of donor concentration and thickness of Si-doped InGaP layers are +4.5% and + 1.5%. These values are small enough for IC applications. The mobility at 4.2 K and the two-dimensional electron gas concentration obtained from Shubnikov-De Haas oscillation measurements are 89,300 cm2/V.s and 8.9x1011 cm-2 for samples with a spacer thickness of 5.5 nm. HEMT IC structures were grown to evaluate the device characteristics. It was shown that enhancement-and depletion-mode HEMTs can be fabricated on the same wafer by selective etching technique. The characteristics of the transistors exhibit no instability at 77 K.

Nuclear Instruments and Methods in Physics Research, 1982

ABSTRACT

A method for fabricating an SOI structure which in cludes the steps of contacting a single crysta... more A method for fabricating an SOI structure which in cludes the steps of contacting a single crystal layer of a group III-V compound semiconductor material to a single crystal substrate of sapphire such that a principal surface of said single crystal layer establishes an inti mate contact with a corresponding principal surface of said single crystal substrate and bonding the single crys tal layer and the single crystal substrate with each other while elevating a temperature.

MRS Proceedings, 1986

ABSTRACTThe measurement of Shubnikov-de Haas(SdH) oscillation is proposed as a new technique for ... more ABSTRACTThe measurement of Shubnikov-de Haas(SdH) oscillation is proposed as a new technique for evaluating the quality of a heterointerface. The first excited state of 2-dimensional electron energy levels is determined for several samples using the measurements of SdH oscillation. Lower values of the first excited state energy are found for the samples with a low mobility. The low value can be approximately explained in terms of graded interface model.