摘要:

Hydrogenated amorphous silicon alloy films were formed by ionized‐cluster beam deposition of silicon in relatively low gas pressure of hydrogen, in a range of 10−5–10−4Torr. Films with optical band gap of 1.3–1.9 eV could be formed. Effective hydrogenation seems to be due to the enhanced adatom migration effect and to the kinetic and the ionic charge effects of the clusters which are characteristics of the ionized cluster beam deposition. For doped film deposition, hydrogen gas mixed with phosphine or diborane was used. By this method, puren‐ andp‐type films could be reproducibly formed at practical deposition rates by changing gas flow into the deposition chamber. The deposited films have good adhesion and show smooth surface and thermally stable characteristics. Thep‐i‐ndiodes formed by this method showed good performance.

ISSN:0021-8979    

DOI:10.1063/1.332141

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Effects of pulsed electron beam annealing (PEBA) are investigated by computer simulations of a thermal process from a one dimensional heat flow model. Experimental studies are presented for phosphorus‐implanted silicon samples. Characterization of PEBA specimens, realized by means of electron channelling patterns observed with a scanning electron microscope (SEM), indicate good regrowth. Comparison made between conventional thermal annealing and pulsed electron beam annealing shows that PEBA removes defects associated with thermal annealing. Crystallographic studies have been made on a series of samples annealed with different fluences (from 1.0 up to 1.6 J/cm2). SEM observations carried out using the electron channelling imaging method and transmission electron microscope (TEM) observations show the existence of dislocations and subgrain boundaries, with a density increasing with fluence. Polygonization seems to indicate that climb as well as glide are active in the dislocation mobility.

ISSN:0021-8979    

DOI:10.1063/1.332142

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The reactive ion etching of (100) GaAs in pure CCl2F2and CF4discharges, as well as in mixtures of Ar and CCl4, CCl2F2, or CF4, has been investigated. Anisotropic etching with removal ratesRof up to 800 nm/min have been obtained in reactive discharges operated at a pressure of 5.3 Pa (40 mTorr) and a target voltage of −3 kV. The physical sputtering rate in pure Ar discharges operated under the same conditions was only 40 nm/min. A combination ofinsituoptical emission and absorption spectroscopies have been used to show that in both pure and dilute (up to 90 mole % Ar) halocarbon discharges, physical sputtering of atomic Ga and As is not a primary etching mechanism for GaAs, although ion bombardment does play a critical role in the overall process. Transient glow discharge optical spectroscopy measurements demonstrated that whileRincreased with increasing Cl/F ratios in the etch gas, the steady state carbon concentration at the GaAs surface also increased indicating that carbon accumulation is not the rate limiting step to etching. Rather, the rate limitation is provided by the desorption kinetics of gallium halides which we believe are ejected primarily (except in pure CCl4) through ion‐assisted processes as the reduced radicals GaFxand/or GaClx(x=1 or 2). A phenomenological model is proposed to provide a qualitative description of the etching behavior of GaAs in mixed halocarbon/inert gas discharges.

ISSN:0021-8979    

DOI:10.1063/1.332143

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We report the first efficient photoanode with a negative flatband potential, consisting ofn‐Fe2O3andn‐Si. An anodic current of ∼0.8 mA/cm2was observed at 0 V SCE in 0.1 M KOH solution under an illumination of ∼60 mW/cm2. A photocurrent rose at ∼−0.3 V SCE under the same condition. An electronbeam evaporation of Fe, followed by its oxidation at 700 °C under 5×10−2Torr was successful in obtaining an efficient photoanode. The surface structure was analyzed using x‐ray photoemission spectroscopy (XPS) and Auger‐electron spectroscopy (AES) techniques and capacitance‐voltage measurements. XPS spectra revealed that the surface structure was composed of Fe2O3‐Fe3O4‐Si. XPS signals showed that the SiO2phase also coexisted at the top surface probably due to interdiffusion of Si. Depth profiles were obtained by the AES technique.

ISSN:0021-8979    

DOI:10.1063/1.332144

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Potential barriers responsible for nonlinear conduction in ZnO ceramic semiconductors (cersems) have been observed by both the intensity andY‐modulation voltage contrast secondary electron microscopy techniques. The barriers exist at a grain‐intergranular interface and extend into the conducting ZnO grains. The applied voltage is distributed uniformly across the barriers. No electrical shorting of the barriers has been observed at fields exceeding the breakdown.

ISSN:0021-8979    

DOI:10.1063/1.332145

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We report the propagation characteristics of magnetostatic surface waves in a rectangular yttrium iron garnet film placed between strips of mumetal and in the plane of the strips. The microstrip excitation structure was designed so as to permit the strips to extend along the entire path of propagation, thereby minimizing field nonuniformities in the longitudinal direction. These experiments suggest that nonuniform in‐plane fields can be used to alter the dispersion characteristics of the waves. A theoretical argument is also presented describing a possible energy localization mechanism in nonuniform in‐plane fields. In addition, experiments are described in which nonuniform fields caused by a slot in a mumetal covering layer are used to guide magnetostatic surface waves through a turn of 160°.

ISSN:0021-8979    

DOI:10.1063/1.332146

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Experiments are reported demonstrating divergence and flutter instabilities in an electrodynamic maglev vehicle. The conducting guideway consists ofL‐shaped aluminum segments attached to a rotating wheel and qualitatively simulates the Japanese full scale guideway at Miyazaki. The model vehicle employed rare earth permanent magnets. Quantitative tests for a coupled yaw‐lateral vibration show both divergence and flutter. The divergence leads to two stable equilibrium yaw positions, while the flutter instability leads to limit cycle oscillations coupling yaw and lateral motions in the neighborhood of the drag peak. A theoretical model based on actual magnetic force measurements is shown to predict this dynamic behavior as functions of vehicle speed and geometry.

ISSN:0021-8979    

DOI:10.1063/1.332147

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The effect of finite coil thickness on the magnetic field produced by a magnetic deflection coil in the shape of a long right circular cylinder is calculated. It is found that the higher ‘‘multipole’’ contents of the field (i.e., the coefficients of higher order terms in a Fourier expansion about the coil axis) decrease by progressively larger percent amounts compared to their values for a coil of zero thickness.

ISSN:0021-8979    

DOI:10.1063/1.332148

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Light deflection is achieved by optically changing the characteristics of a transient index modulation generated in an optical material by two interfering beams. Using a novel technique to maintain the Bragg condition, diffraction efficiency is kept constant during the whole deflection process.

ISSN:0021-8979    

DOI:10.1063/1.332149

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The flow of low‐beta laser‐produced plasmas across a magnetic field was studied. When a metallic plate was placed adjacent to the plasma stream, low atomic mass plasmas were confined to a region 17 cm from the target. High mass plasmas were not affected within the limits of the vacuum chamber. These observations confirmE×Bdrift as the mechanism of cross‐field flow.

ISSN:0021-8979    

DOI:10.1063/1.332150

出版商:AIP    

年代:1983

数据来源: AIP