摘要:

Dislocation damping in deformed single‐crystal silicon has been measured in the frequency range from 400 cps to 70 kc/sec and at temperatures between 500° and 1200°C. At low temperatures the logarithmic decrement shows a thermally activated rise with temperature, of activation energy 1.6 eV, varying approximately inversely with frequency. Deviation from this behavior is seen at the lower frequencies, where a peak appears near 800°C, followed by a second rise with temperature which is significantly faster than the initial rise. The results are interpreted in terms of an extensible string model, in which it is assumed that the dislocation is pinned by point defects which may diffuse with the dislocation. Agreement is obtained between theory and experiment for very reasonable values of mean dislocation length, and values of dislocation damping constant consistent with a geometrical kink diffusion model. The activation energy of motion for the pinning points is about 3.1 eV. Measurements on indium antimonide yield similar results, and it is supposed that a similar interpretation applies, although the data is not complete. The ratio of activation energies in the two materials is approximately the same as that for bond‐breaking, which is believed to be the major energy barrier to kink diffusion in covalent materials.

ISSN:0021-8979    

DOI:10.1063/1.1714561

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

The shear strengths of solid argon and krypton have been measured by both direct and indirect extrusion techniques in the temperature ranges 32° to 81°K and 59° to 112°K, respectively. The shear strength of these materials is found to increase from 5 bars near the melting point to 100 bars near the lower temperatures indicated. Based on shear strength measurements these solidified gases are sufficiently soft and plastic somewhat below their melting points to serve as suitable pressure transmitters for high‐pressure experiments. Because their shear strengths increase rapidly as temperature is reduced, it is recommended that, where practical, pressure be applied just below their melting points and the test apparatus subsequently cooled to the temperature of interest.

ISSN:0021-8979    

DOI:10.1063/1.1714562

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A center has been observed in MgO which has a [100] symmetry and gives rise to mechanical relaxation with associated activation energy of 0.64 eV. The pre‐exponential frequency factor is 1.8×1011sec−1, an anomalously low value which, it is suggested, indicates that the defect reorientation involves a primarily electronic transition. The center is stable only at high temperatures, decaying to a lower thermal equilibrium value below about 850°C. No spin resonance, dielectric loss, or optical absorption associated with the center has been observed, and studies of the effects of various treatments have not allowed the defect to be identified.

ISSN:0021-8979    

DOI:10.1063/1.1714563

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

The deformation of epitaxial silicon films grown on single‐crystal sapphire has been measured. The range of silicon thicknesses was between 1 and 46 &mgr; and the range of sapphire thicknesses was between 127 &mgr; (0.005 in.) and 508 &mgr; (0.020 in.). The deformation of the films was found to be proportional to silicon film thickness and decreased with increasing sapphire thickness. For sapphire disks of 0.95 cm (⅜ in.) diameter and 250 &mgr; (0.010 in.) thickness the proportionality constant was unity. The stresses in the deformed silicon films have been estimated on the basis of linear beam theory and were of the order of 109to 1010dyn/cm2. The silicon films were under compression and the sapphire was under tension. No physical damage to the films was observed under these stresses, but these stresses should be sufficient to affect the electrical properties of the films.

ISSN:0021-8979    

DOI:10.1063/1.1714564

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A preliminary study of the oxidation of silicon by a moderate density oxygen gas plasma has provided two methods for oxidizing silicon rapidly at low temperatures. The oxidation process has unique characteristics which allow for masking against the growth of the film. A probable mechanism for the oxidation process is presented.

ISSN:0021-8979    

DOI:10.1063/1.1714565

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

The diffusion‐limited climb rate of a straight dislocation immersed in a nonequilibrium concentration of point defects was calculated in the quasisteady‐state approximation. It was shown that this approximation should apply in many cases of interest. Full account was taken of the effect of the dislocation climb motion while treating the problem of the diffusion of defects from (or to) the dislocation. The effect of the climb motion was expressed in terms of the dimensionless parametervR/2D, wherevis the climb velocity,Ris the radius of the diffusion field of the climbing dislocation, andDis the point‐defect diffusivity. ForvR/2D«1, the effect of the climb motion was negligible. ForvR/2D»1, the climb rate tended to be faster than that calculated by ignoring the climb motion. It was shown, however, that under usual conditions the climb motion could never be an important factor affecting the diffusion‐limited climb rate. The results were applied briefly to some recent data for climbing dislocations in gold.

ISSN:0021-8979    

DOI:10.1063/1.1714566

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A novel x‐ray technique and its application to semiconductor problems is described. The technique is capable of recording large‐area transmission topographs of crystal slices as processed in modern semiconductor device technology. The technique is nondestructive and, therefore, crystal slices can be examined after each processing step. This technique and some of the results obtained are discussed, such as x‐ray topographs of diffused transistor structures, recorded in the presence of elastic and/or frozen‐in lattice deformations.

ISSN:0021-8979    

DOI:10.1063/1.1714567

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

Mathematical models, including a generalized diffusion equation with time varying coefficients, are developed which approximate the propagation of both the initial neutron and the initial gamma radiation from nuclear weapon detonations. Typical plots of neutron and gamma pulse shapes obtained from these models are compared and show that for many cases the gamma spike, or unscattered components of gamma radiation, is predominant. Therefore, it is concluded that for most cases the simplified gamma spike formula commonly used in calculating the radiation environment is appropriate for use in predicting the effects of nuclear weapon detonations upon electronic equipment.

ISSN:0021-8979    

DOI:10.1063/1.1714568

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

Allowance for traps in certain space‐charge environments produces changes in the mathematical formalism which make it difficult to determine spatial variations in potential and the negative‐positive charge distribution. The trap‐free model for the blocking electrode can be extended into this realm by appropriate accommodation of the equations of continuity for specified kinetics of the trap system. The tendency of traps seems to be a moderation of the spatial fall‐off of potential with more gradual build‐up and decay of the charge densities. The nonlinear Poisson equation has been solved analytically by the development of powerful series methods, demonstrating that machine integration can be avoided.

ISSN:0021-8979    

DOI:10.1063/1.1714569

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

Vapor‐deposited nickel films in the thickness range 700 to 4000 Å were stressed to fracture in uniaxial tension in the as‐deposited condition and after annealing at 650°C for 3 h or at 700°C for 5 min. The existence of a strength dependence on thickness was observed for both the as‐deposited and annealed films; however, the as‐deposited films were 1½ to 2 times stronger than annealed films of comparable thickness. The thickness‐strength relationship for as‐deposited films was found to be &sgr; = 134 kg/mm2+(1675 Å kg/mm2)t−½, while that for the annealed was &sgr; = (−.0245 kg‐mm−2/Å)t+155.6 kg/mm2. Both the annealed and as‐deposited films exhibited fracture strengths in excess of bulk nickel of analogous structure.It is believed that the observed high strengths of as‐deposited nickel films are due in part to the high defect density arising from the vapor deposition process and to the proximity of the film surfaces which further inhibits dislocation motion. With regard to the latter, a mechanism involving dislocation pile‐up is proposed.

ISSN:0021-8979    

DOI:10.1063/1.1714570

出版商:AIP    

年代:1965

数据来源: AIP