摘要:

High‐resolution charge patterns at various charge densities were written on Teflon TFE foils using a 10‐kV electron beam with a 1/2‐&mgr;m spot diameter. Resolutions of 50–100 line pairs/mm were observed by examination with an electron beam and use of xerographic development techniques. Charge spreading in the Teflon and the examination processes were among the factors limiting resolution. Development of stored patterns up to 3 months after their writing showed that resolutions of 100 line pairs can be maintained for this period. Comparison of the results for heat‐sealed samples with those for nontreated samples showed an absence of any marked pattern deterioration due to heat sealing.

ISSN:0021-8979    

DOI:10.1063/1.322884

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

The lateral distribution of damage introduced in semiconductors by ion implantation is studied theoretically using the theory of Lindhardetal. This theoretical study is experimentally verified by a backscattering measurement of the damage formed by ion implantation into a tilted target. It is found that the spread of lateral damage is largest at a position near to or deeper than the ion projected range, and that the ratio of the lateral damage spread from a mask edge to the longitudinal damage spread from the surface is less than unity even in the case of implantation of light ions. For instance, the ratio is about 20% in the case of 100‐keV B+implantation into Si. It is also found that the ratio becomes smaller as the energy of the implanted ions increases or as the ions become heavier.

ISSN:0021-8979    

DOI:10.1063/1.322885

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

The film resistance has been monitored during the deposition of gold onto glass at room temperature in UHV. The film structure during the growth could be related to the depositing resistance and to the resistance during aging after halts in the deposition. In the discontinuous stage the tunneling length of electrons increases exponentially with aging times larger than 2 h. The electric‐field‐dependent resistance was measured 20 h after deposition. An Ohmic region at low fields was followed by a region proportional to the square root of the applied field.

ISSN:0021-8979    

DOI:10.1063/1.322886

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

A replication technique is used to determine,insitu, the structure of thin lithium deposits prepared at 6 K. It is shown that perfectly smooth deposits are not always obtained. It follows, as in the case of deposits prepared at room temperature, that optical conductivity is not perfectly described by the sum of an intraband term and an interband term, but must take into account a supplementary term that characterizes an absorption due to granular structure of the deposit or to surface roughness defects. It is shown that certain deposits of lithium, prepared at low temperature, are made up of a two‐dimensional distribution of grains on a continuous layer of metal. In this case the supplementary term results from collective oscillations of conduction electrons in the metallic grains. From this, it can be concluded that most of the optical measurements made on the thin deposits of lithium (and on alkali metals in general) in all likelihood involve systematic errors, and should be corrected before being collated with theory.

ISSN:0021-8979    

DOI:10.1063/1.322887

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Simple wave solutions are presented for the case of pressure shear waves in a hyperelastic material which models fused silica. The adiabatic strain energy function of this material is written as an expansion to third‐order terms in the strains. The analysis includes interaction of the simple waves with a free surface. Comparison of computed particle velocity‐time profiles for the free surface with profiles observed in experiments shows good agreement. The solutions also indicate that the shear wave propagating in a shear‐strain‐free region of fused silica is essentially nondispersive.

ISSN:0021-8979    

DOI:10.1063/1.322888

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

The optical dielectric constant &egr;∞of Pb1−xSnxTe has been measured for Sn fractionsxof 0.0, 0.24, 0.36, 0.39, and 0.40 in the temperature range 6–120 K and at 300 K. The value of &egr;∞increases from 33 for PbTe at 300 K to 60 for Pb0.61Sn0.39Te at 6 K. This maximum value appears to occur at a composition and temperature close to the L‐point band inversion. However, the relative insensitivity of &egr;∞to carrier concentration suggests that this increase in &egr;∞near band inversion arises from motion of the bands throughout the Brillouin zone rather than from a change in L‐point ionicity, as suggested by Wemple.

ISSN:0021-8979    

DOI:10.1063/1.322889

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

The time‐dependent temperature distribution of a thin‐film stripe has been solved rigorously using two successive Laplace transforms on both time and coordinate. For a good conducting stripe with a &dgr;‐shaped crack it is shown that the temperature distribution can be very adequately described by the steady‐state solution provided only that the time scale involved is of the order of 10−3sec or longer. No localized hot spot is possible, for whatever reasons, for a good conductor. However, if heat generation outpaces heat conduction, as would be the case for a poor conductor, a localized temperature becomes quite realizable. Finally, if stripe cracking is developed via grain‐boundary grooving processes somewhere along the stripe, in particular near the anode, void formation there is simply a natural consequence of the temperature‐grandient effect.

ISSN:0021-8979    

DOI:10.1063/1.322890

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

The nature of the damage to GaAs caused by exposure to a 10.6‐&mgr;m laser beam at power densities of 1130, 2260, and 5650 W/cm2was determined by transmission electron microscopy. At 5650 W/cm2damage was observed at the surface in the form of craters of 80 &mgr;m or larger in diameter. Within the craters were found concentric zones spreading out from the center and consisting of (1) an amorphous region, (2) a region showing striations and skeletal crystalline walls in an amorphous matrix, and (3) a mixed amorphous‐crystalline region containing small rounded clusters of dislocations, some of which were helical. In one case crystalline arsenic was found near the central zone. The results observed at this power level indicate that thermal effects have caused melting, evaporation, and decomposition. It is suggested that the skeletal walls and the striations parallel to {110} planes are caused by preferential evaporation or decomposition and may be related to the presence of small precipitates or chemical inhomogeneities along {110} planes of GaAs as observed by others. Damage near the entrance surface at low power densities, and at the exit surface for the highest power density, consisted of unique clusters of dislocations spreading out along orthogonal ⟨110⟩ directions up to 3 &mgr;m. Although the direct cause of these dislocations could not be determined, it suggested that they result from cracking or cleavage of the crystal due to stresses caused by localized heating at sites of precipitates, occlusions, or other faults in the crystal.

ISSN:0021-8979    

DOI:10.1063/1.322891

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Samples of polycrystalline Au, Ta, and ThO2were bombarded by 5–15‐keV beams of H+1, H+2, H+3, D+1, and D+3ions. The backscattered positive and negative hydrogen ions were energy analyzed by a spherical condenser. For Au and Ta both the positive and the negative spectra start with zero intensity at zero energy and reach maxima, whose position depends on the primary energy and the ion species. For ThO2the positive spectrum is similar but the number of negative ions shows no maximum and is largest at energies below 1 keV and continues to decrease with increasing energy. With decreasing work functions of the target materials the number of backscattered negative ions increases. The ratio of negative‐to‐positive backscattered ions is larger than unity at low energies in the cases of Au and ThO2. A comparison of proton and deuteron results shows that the ratio is equal for ions of equal velocities. For Ta and ThO2this ratio is considerably larger when the targets are bombarded with molecular ions as H+2, H+3, D+2, and D+3than when bombarded with the corresponding atomic ions H+and D+with equal energies per atom.

ISSN:0021-8979    

DOI:10.1063/1.322892

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Si depth profiles and contaminants in Si‐doped Al films deposited on SiO2by electron‐gun evaporation at different base pressures have been measured. The experimental techniques employed were Auger electron spectroscopy combined with ion milling for chemical analysis and depth profiling, and transmission electron microscopy for film structure studies. Auger analysis showed that at intended doping levels of 1 and 2 at.% (previously calibrated using atomic absorption spectrometry) the Al films contained 0.9 and 1.9 at.% Si, if the total Si content was averaged over the entire film thickness. However, most of the Si had migrated to the Al/SiO2interface after deposition at 300 °C and formed precipitates which nucleated at or near the Al/SiO2interface. The major film contaminants were C and O, whose concentrations were directly related to the pressure during deposition. The lowest detection limits with the Auger technique were ∼0.01 at.% (100 ppm) for both C and O, attained using a 50‐&mgr;A incident electron beam current and a scan time of <30 sec per element.

ISSN:0021-8979    

DOI:10.1063/1.322893

出版商:AIP    

年代:1976

数据来源: AIP