Showing papers by "Mitsubishi Electric published in 1977"
TL;DR: In this paper, a tradeoff between the cutoff frequency and the efficiency as a function of the hole concentration is discussed, and a new idea of the "figure of merit" as a product of the cutoff and efficiency is introduced.
Abstract: Cutoff frequency of GaAs-(Ga,Al)As double heterostructure light-emitting diodes (LED's) is investigated as functions of design parameters, such as hole concentration of the active layer, thickness of the layer, and injected current density. The cutoff frequency increases with increasing the hole concentration and injection current density, and with decreasing the active layer thickness. They are theoretically explained by the simple equation proposed in this paper by setting the recombination constant B to be 1.1 × 10-10cm3/s. A tradeoff between the cutoff frequency and the efficiency as a function of the hole concentration is discussed. By introducing a new idea of the "figure of merit" as a product of the cutoff frequency and the efficiency, the hole concentration is optimized to be 3 × 1018cm-3for Ge-doped active layer.
86 citations
TL;DR: Conditions were found to fabricate the waveguides of the required number of modes (TE modes) and effective indices for the wavelength of a He-Ne laser and a GaAs-GaAIAs double heterostructure laser.
Abstract: The investigations were carried out on optical waveguides obtained by thermal diffusion of Ti into LiNbO3 single crystals. In the Ti-diffused LiNbO3 slab waveguides, the relationships of the refractive index profile (index change at the surface, diffusion depth) to various diffusion conditions were examined. Conditions were found to fabricate the waveguides of the required number of modes (TE modes) and effective indices for the wavelength of a He–Ne laser (0.6328 μm) and a GaAs–GaAIAs double heterostructure laser (DH laser) (0.8730 μm). The slab waveguides of the required number of modes and effective indices could be obtained by adjusting only the thickness of evaporated Ti film.
46 citations
TL;DR: In this article, the conditions for making ohmic contacts with low specific contact resistance on n-type GaAs by Au Ge Ni alloys were suggested based on the results of liquid phase epitaxial growth experiments.
Abstract: Epitaxial GaAs layers are grown from Au Ge and Au Ge Ni melts in order to study Ni/Au Ge/GaAs alloyed contacts. The solubility of GaAs in Au Ge and Au Ge Ni alloys has been measured. The electrical behavior of Au, Ge and Ni in Ni/Au Ge/GaAs alloyed contacts is also discussed. Based on the results of liquid phase epitaxial growth experiments, we suggest the conditions for making ohmic contacts with low specific contact resistance on n -type GaAs by Au Ge Ni alloys. The specific contact resistance of Ni/Au Ge/GaAs alloyed contacts is also measured.
43 citations
TL;DR: In this article, two new structures of lateral-injection transverse junction stripe (TJS) lasers, in which the stripe geometry is formed by the double heterojunctions, have been developed.
Abstract: Two new structures of lateral-injection transverse junction stripe (TJS) lasers, in which the stripe geometry is formed by the double heterojunctions, have been developed. These lasers, the homojunction type and the single-heterojunction type, have a self-reverse-biased p-n junction for concentrating current into the narrow active region. The temperature dependence of the threshold current has been very much improved in one of the new structures, the homojunction type, and is fair compared with those of good conventional broad-contact lasers. The threshold current does not increase rapidly up to 350 K in the homojunction lasers. These lasers exhibit improved characteristics of low threshold, the single longitudinal mode oscillation as well as the single fundamental transverse-mode oscillation, and "kink-free" behavior in the current depedence of the light-output power.
42 citations
TL;DR: The experimental results strongly suggest that H 2 S and H 2 O adsorb in the molecular states at room temperature and O 2 is first adsorbed in a molecular state, then adsorbs as atoms, and finally oxidizes forming SiO 2 as mentioned in this paper.
34 citations
TL;DR: In this article, a GaAs-GaAlAs LED with a self-aligned sphere lens was developed for efficient coupling to low-less optical fibers as a light source for fiber optic communications.
Abstract: A practical new structure of the high radiance GaAs-GaAlAs LED with a self-aligned sphere lens has been developed for efficient coupling to low-less optical fibers as a light source for fiber optic communications. In this new configuration, the sphere lens is automatically settled into the center of the light-emitting surface by an etched hole containing clear epoxy resin. When applied to a low-loss optical fiber ( NA = 0.14 , core diameter: 80 µm), a coupling efficiency in excess of 9 percent has been reproducibly achieved for an LED structure with an emitting-area diameter of 35 µm and with a lens having a diameter of 100 µm and a refractive index of 2.0. Using an LED with a light-emitting-layer carrier concentration of 3 × 1018/cm3, an optical power of 150 to 200 µW coupled into the fiber and a cut-off frequency (optical power down to ½) of about 90 MHz have been reproducibly obtained.
33 citations
TL;DR: In this paper, it was proposed that NO and NH3 are absorbed in molecular states at room temperature, and the similarity of the loss spectra for NO and O2 strongly favors with our recent proposal that O2 is adsorbed as molecules at the initial stage of the oxidation.
29 citations
TL;DR: In this article, the thermal decomposition of transformers is considered on the basis of thermodynamic equilibrium and a theoretical interpretation of the analysis of dissolved gases in transformer oil is given.
Abstract: The thermal decomposition of hydrocarbons is considered on the basis of thermodynamic equilibrium. This consideration gives a theoretical interpretation of the analysis of dissolved gases in transformer oil. This kind of analysis is now widely used for the diagnosis of transformers in operation. The thermal decomposition of hydrocarbons is divided into primary and secondary stages. From the thermodynamic equilibrium follows that more saturated hydrocarbon gases are evolved than unsaturated ones in the primary decomposition which is dominant at a lower temperature. At a higher temperature, methane, ethylene, and propylene are evolved more than other hydrocarbon gases in the secondary decomnposition. Overheating of transformers may be estimated by the ratio of the three gases mentioned above. The gas composition is calculated in the state of equilibrium. Experimental data on the thermal decomposition of hydrocarbon and gases in transformer oil, although not obtained in the state of equilibrium, show good agreement with the theoretically calculated result.
27 citations
TL;DR: In this article, a design method of GaAs MESFET oscillator using large-signal S-parameters has been discussed, which has resulted in power output of 45 mW at 10 GHz with 19-percent efficiency.
Abstract: A design method of GaAs MESFET oscillator using large-signal S-parameters has been discussed. Together with the measurement results of the dependence of Iarge-signall S-parameters on power levels and bias conditions, computer analysis of the equivalent circuit for MESFET'S has qualitatively clarified the large signal properties of MESFET'S. On the basis of these findings, S-parameters have been designed for the MESFET oscillator over the frequency range of 6-10 GHz, which has resulted in power output of 45 mW at 10 GHz with 19-percent efficiency, and 350 mW at 6.5 GHz with 26-percent efficiency, respectively. Good agreements between predicted and obtained performances of MIC positive feedback oscillator have been ascertained, verifying the validity of the design method using large-signal S-parameters.
26 citations
01 Jan 1977
TL;DR: In this paper, the authors have developed a new thyristor called Static Induction Thyristor, which showed a short fall time of current (0.1 µsec) and a high forward blocking voltage (700 V).
Abstract: We have developed a new thyristor called Static Induction Thyristor (SI Thyristor) which showed a short fall time of current (0.1 µsec) and a high forward blocking voltage (700 V). The SI thyristor has a combined structure of an N channel Static Induction Transistor and a PNP transistor. It has both capabilities of gate turn-on and gate turn-off according to the value of gate biasing voltage. We have investigated the turn-off mechanism for the high voltage device and have clarified the relation between the device parameters and carrier decaying time responsible for current fall time. From these investigation, we have improved the switching characteristics of high voltage device.
23 citations
TL;DR: In this article, the authors investigated the relationship between transient behavior and spectral properties of transverse junction stripe (TJS) laser and derived the effective pump rate of TJS laser by considering the transient gain peak shift due to junction temperature rise during the application of modulation current.
Abstract: The transverse junction stripe (TJS) laser has a unique structure and exhibits significantly simple mode properties. This paper reports the relation between transient behavior and spectral characteristics. The discrepancy of the experimental pulse response of TJS lasers from the solution by conventionally simple treatment of rate equation is discussed, and it was found that by taking the effective pump rate into consideration in the rate equation a fairly good but qualitative explanation can be given for the experimental fact that the TJS lasers hardly tend to show relaxation oscillation. Effective pump rate is deduced on the basis of the transient gain-peak shift due to junction temperature rise during the application of modulation current and is deeply concerned with single-mode operation mechanism in TJS lasers. It becomes evident from the experiment that TJS lasers show a good response waveform without relaxation and with very little PCM pattern effect in excess of a bit rate of 100 Mbits/s.
TL;DR: Periodic modulation of the propagation constants of a propagation medium is proposed as a method to vary the effective coupling coefficient of the two coupled waves and as a new method for phase matching as mentioned in this paper.
TL;DR: Wear characteristics of MgO single crystals sliding in the cleavage plane on a low carbon steel disk were investigated in this paper, showing that the wear process at all sliding velocities indicated a discontinuous or stepwise removal of material.
01 Jan 1977
TL;DR: In this article, the experimental results of a DSA MOS memory fabricated by full ion implantation techniques to achieve better threshold voltage controllability will be dcscribed, and the memory cell uses a 1 Tr/cell structure to avoid Vth to minimize inverse connection effects due to high voltage.
Abstract: DIFFUSION-SELF-ALIGNED (DM) M O S I C ~ ' , or D M O S ~ have received attention as subnanosecond and high density devices. In this paper, the experimental results of a DSA MOS memory fabricated by full ion implantation techniques to achieve better threshold voltage controllability will be dcscribed. Access time is 60 ns; power consumed is 950mW. Figure 1 shows cross section of the DSA E-D inverter. It is apparent from the figure, that the effective channel region of the DSA transistor is determined by the diffusion length difference between boron and arsenic layer. All dopants were deposited by ion implantatio-n method on P(71) Si substrate; resistivity was 100 "200 Q-cm, crystal orientation (loo), respectively. The threshold voltage of the device was controlled within 1.20 ? 0.15V and the effective channel length was 0.4 pm. The gain factor was 5 times larger than that of the conventional NMOS3. Features of the DSA MOS process are: 1 ) E-D gate achieved by N-channel 71 planar technique; 2 ) selective oxidation process (SOP) adapted to obtain high packing density and to reduce surface steps; 3) Si gate also used for a smaller feedback capacitance and higher packing density; and 4) all dopants deposited by ion implantation method to improve control of threshold voltage. To evaluate the basic electrical characteristics of these devices, 1 9 stag: ring oscillators have been fabricated by varing process parameters. Figure 2 shows the propagation delay time versus power dissipation, where the parameters were varied for the amount of channel dope to the depletion FET and power supply voltages. In the unhatched region, the driving capability of the DSA MOS FET is smaller than that of the load FET, thus the inverter does not operate. The minimum power delay product (0.05 pJ) and the minimum propagation delay time (0.32 ns) are shown in the ploy. Using this process, a 4096-bit fully decoded dynamic R/W random access memory was developed (Figure 3) using a 5 p m minimum as a base. The memory cell uses a 1 Tr/cell structure to avoid Vth to minimize inverse connection effects due to high __
TL;DR: In this article, the behavior of a flexible appendage attached to a spacecraft containing a rotor is investigated with particular emphasis on the behavior near resonance, where the natural frequency of the appendage is approximately equal to twice or half the nutational frequency.
Abstract: Thermally induced vibrations of a flexible appendage attached to a spacecraft containing a rotor are investigated with particular emphasis on the behavior near resonance. Resonance will occur when the natural frequency of the appendage is approximately equal to twice or half the nutational frequency. In the first case, it is possible for the vibration of the appendage to be unstable through the instrumentality of the parametric excitation. Criteria for the onset of the unstable motion of the appendage are established. In the second case, the vibration of the appendage builds up to a finite value through the resonant exielation. The stationary amplitude of the vibration is obtained. The method of averaging is employed to analyze the phenomena. Finally, the dynamic characteristics of the system near the resonance are investigated numerically.
TL;DR: In this paper, the threshold voltage controllability of diffusion selfaligned (DSA) MOS FET fabricated by a full ion implantation and N2 drive-in technique has been examined and analyzed.
Abstract: Threshold voltage (Vth) controllability of diffusion self-aligned (DSA) MOS FET fabricated by a full ion implantation and N2 drive-in technique has been examined and analyzed As the p-type diffused region (base) and the n-type diffused region (source) were formed by this method, the impurity profiles of these layers became reproducible and Vth controllability were improved as compared with the usual thermal predeposition process A simplified Vth model showed a good agreement with the experimental results The performance of DSA ED MOS IC has been also discussed In the 19 stage ring oscillators, the propagation delay time per unit gate was 036 ns (Vdd=80 V) for high speed design and the power-delay product was 0055 pJ (Vdd=27 V) for low power design A 1024-bits random access memory has been developed on the basis of above mentioned results, and the access time of 50 ns has been obtained
20 Jun 1977
TL;DR: Gases dissolved in transformer oil are analyzed for the diagnosis of transformers in operation in this article, and it is concluded that transformer oil generates a small amount of hydrogen even at the normal operating temperature.
Abstract: Gases dissolved in transformer oil are analyzed for the diagnosis of transformers in operation. In some newly installed transformers, we found that the combustible gases dissolved in the oil were mostly hydrogen. From considering the dehydrogenation equilibrium of saturated hydrocarbons it is concluded that oil generates a small amount of hydrogen even at the normal operating temperature of transformers, and there may be catalytic action of metal on the dehydrogenation of oil in these transformers. We found that stainless steel is such a catalyst.
TL;DR: In this article, the influence of oxygen in ambient gas during liquid-phase epitaxial growth on a double-heterostructure (DH) wafer is investigated, and the correlation between DSD's and etch pits is examined.
Abstract: The influence of oxygen in ambient gas during liquid-phase epitaxial growth on a double-heterostructure (DH) wafer is investigated. The oxygen incorporated into grown layers seems to be associated with the formation of crystal defects such as so-called dark-spot defects (DSD's) and saucer pits. When the oxygen concentration is reduced less than 0.03 ppm, crystal defects such as DSD's and saucer pits drastically decrease in the epitaxial layers. Al added into Ga solutions behaves as the getter of the oxygen in the Ga solutions and prevents the formation of DSD's in the active layers. The correlation between DSD's and etch pits is examined. All of the dislocations do not always contribute to the formation of DSD's. The formation of DSD's depends on oxygen concentration in the ambient hydrogen gas. In DH lasers fabricated from DH wafers grown under the extremely low oxygen concentration, the operating life at room temperature exceeds 10 000 h at the present time.
TL;DR: The digital relay system by micro-processors was developed with the optical fiber data transmission facilities to protect the transmission signals from surge and noise disturbances and successfully went through the factory tests on the artificial transmission line (ATL).
21 Jun 1977
TL;DR: In this paper, a design method of GaAs MESFET oscillator using large signal S-parameters has been discussed, together with the measurement results of the dependence of large signal parameters on power level and bias condition.
Abstract: A design method of GaAs MESFET oscillator using large signal S-parameters has been discussed Together with the measurement results of the dependence of large signal S-parameters on power level and bias condition, computer analysis of the equivalent circuit for MESFET's has qualitatively clarified the large signal properties of MESFET'S On the basis of these S-parameters has been designed the MESFET oscillator over the frequency range of 6-10 GHz, which has resulted in power output of 45 mW at 10 GHz with 19% efficiency and 350 mW at 65 GHz with 26% efficiency respectively Good agreements between predicted and obtained performance of MIC positive feedback oscillator have been ascertained, verifying the validity of the design method using large signal S-parameters
TL;DR: In this paper, a series of styrene-methyl methacrylate (SM) and styrenemethacrylic acid (SA) copolymer latices have been prepared by emulsion polymerization using polyoxyethylene nonyl phenyl ether as emulsifier and potassium persulphate as initiator.
Abstract: Series of styrene-methyl methacrylate (SM) and styrene-methacrylic acid (SA) copolymer latices have been prepared by emulsion polymerization using polyoxyethylene nonyl phenyl ether as emulsifier and potassium persulphate as initiator. Trace carboxyl groups were detected both in polystyrene latex and styrene-methyl methacrylate copolymer latices. The stability and electrophoretic behaviour of these latices against barium chloride have been investigated. The values of the critical coagulation concentration (c. c. c.) increased with increasing methacrylic acid content for SA series latices, while they are almost independent of methyl methacrylate content for SM series latices. The effects of methyl methacrylate and methacrylic acid on the change in Hamaker constant were found to be almost identical. The difference inc. c. c. between SM and SA series latices seems to be due to the difference in electrical repulsion caused mainly by carboxyl groups on the surface.
01 Jan 1977
TL;DR: The FA-CMOS as discussed by the authors is based on the conventional silicon gate CMOS process using the selective oxidation process (SOP) technology, which is necessary to form the avalanche injection region capable of programming with low voltage without the breakdown of N+P-junction.
Abstract: The combination of FAMOS and CMOS processes produces a new PROM with high performance and low power. This combined process named FA-CMOS will be described. The FA-CMOS process is based on the conventional silicon gate CMOS process using the selective oxidation process (SOP) technology. It is necessary to form the avalanche injection region capable of programming with low voltage without the breakdown of N+P-junction ( N+diffusion to P-well region ). Arsenic ions are implanted to form this region and the avalanche injection voltages of less than 20 V are obtained. In addition to the above mentioned process, the double diffusion technology simplifies the formation of source-drain and isolation region. Extremely low power ( 0.6 µW/bit ) PROM was successfully fabricated using the FA-CMOS process.
TL;DR: Dependence of the maximum deflection efficiency eta(max) on spreading angle (deltatheta) of such a GOB and that (deltaPhi) of a surface acoustic wave were revealed experimentally and theoretically for He-Ne and GaAlAs double heterostructure (DH) lasers.
Abstract: We have investigated deflection efficiency of thin-film acoustooptic light deflectors for a narrow guided optical beam (GOB). Dependences of the maximum deflection efficiency ηmax on spreading angle (δθ) of such a GOB and that (δΦ) of a surface acoustic wave were revealed experimentally and theoretically for He–Ne and GaAlAs double heterostructure (DH) lasers. ηmax is drastically reduced when δθ increases to δΦ; and ηmax increases with increasing δΦ for fixed δθ. Even for a DH laser having a spectral halfwidth of about 63 A, the spectral distribution scarcely affects ηmax in this deflector. Some restrictions are pointed out in designing the deflector with higher ηmax for a narrow GOB.
TL;DR: GaxIn1-x Sb single crystalline layers grown on GaSb and InSb substrates were prepared in a whole composition range by a liquid phase epitaxial technique as discussed by the authors.
Abstract: GaxIn1-x Sb single crystalline layers grown on GaSb and InSb substrates are prepared in a whole composition range by a liquid phase epitaxial technique. Ga0.82In0.18Sb Gunn diodes are fabricated and preliminary measurements of the oscillator performance in a pulsed operation are obtained. The highest values of maximum efficiency and peak output power are 9.2% at 2.6 GHz and 950 mW at 1.9 GHz, respectively.