摘要:

A new method for computing proximity‐effect corrections for submicrometer electron beam lithography is introduced. It is based on a two‐parameter resist development model and the restatement of the proximity‐effect problem as a linear programming problem. Example solutions in several relevant physical regimes are presented.

ISSN:0021-8979    

DOI:10.1063/1.329802

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The variation in the rate of fluorine loss from electron‐bombarded Na3AlF6films with time, beam‐current density, and temperature is reported. The loss is shown to be due to the emission of F atoms; the observation of F2emission is shown to be an experimental artifact. A kinetic model is proposed which involves movement of fluorine into the bombarded area and which provides a good quantitative fit to a range of experimental data. The value for the cross section for dissociation of Na3AlF6under bombardment with 500‐eV electrons is found to be (1.35±0.4)×10−16cm2.

ISSN:0021-8979    

DOI:10.1063/1.329803

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The variation in the thickness of thin films produced by a scanning laser was calculated and compared with experiment. Fluid flow in the molten‐metal film was induced by surface‐tension gradients generated by the local heating of the laser beam. The surface of the film became rippled, limited by capillary effects and the constraint of the solid substrate. A Nd:YAG scanning laser was used to melt and alloy 2‐&mgr;m‐thick films consisting of Pb and Sn layers. The shape of the thickness profile measured with a two‐beam interferometer agreed with the calculated shape. Measurements of the surface composition indicated that alloying occured and influenced the magnitude of the surface relief. The surface topography of laser alloying and recrystallizing thin films as discussed in the recent literature, is reviewed on terms of the surface‐tension‐gradient mechanism.

ISSN:0021-8979    

DOI:10.1063/1.329804

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A new technique for the transient excitation of conducting targets which introduces no electromagnetic interference is described. A fast rise‐time laser pulse with a 1.06‐&mgr;m wavelength is focused to a power density exceeding approximately 4×109W/cm2on the surface of a conducting target. The local heating of the surface by the laser energy produces thermionic emission which is electromagnetically equivalent to a transient current monopole normal to the target surface at the irradiated spot. This localized current pulse then couples to the modal surface currents on the target. This paper descibes an experimental investigation of this technique for target excitation. The results of several independent experiments and an explanation of the large difference in excitation strengths between targets in air and in vacuum are consistent with a physical model of the excitation mechanism based on surface heating by the optical energy to produce thermionic emission.

ISSN:0021-8979    

DOI:10.1063/1.329805

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

In a well‐defined range of conditions, selenium vapor deposited onto a thermoplastic substrate forms a monolayer array of spherical particles located just beneath the surface. A model for the growth of these particles has been proposed. In it, the particles grow by two mechanisms: (i)capture of selenium molecules diffusing into the substrate, and (ii)coalescence with other particles when they grow into contact. Expressions for both rates are presented and analytical solutions for the time dependence of the numbers and sizes of the particles are devived for two limiting cases—complete condensation (in which all impinging materials become incorporated into the particles) and incomplete condensation (in which re‐evaporation of adsorbed species limits the kinetics). Experimental data confirm the model’s predictions.

ISSN:0021-8979    

DOI:10.1063/1.329807

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The influence of partial substitutions of iron in TiFe by some other 3‐d transition metals on the hydrogenation characteristics of the corresponding ternary (pseudo‐binary) TiFexM1−x(M=Cr, Mn, Co, Ni; 0.5≲x≲1) compounds was systematically investigated. Such substitutions result in two main effects:(i) stabilization of the monohydride &bgr; phases and (ii) reduction of hysteresis in the absorption‐desorption isotherms. A linear dependence of the enthalpies of the monohydride formation on the iron concentration (i.e.x) has been obtained and accounted for by a model assuming local interactions of hydrogen with nearest‐neighbor metal atoms.

ISSN:0021-8979    

DOI:10.1063/1.329808

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A model for ion nitriding is proposed which is based on the formation and diffusion of vacancy‐nitrogen ion pairs. A theoretical expression is developed for the local effective diffusion coefficient of the combined vacancy‐ion pairs which explains the accelerated case hardening associated with ion nitriding as compared with conventional nitriding. Ion‐nitriding experiments on AISI 304 stainless steel were performed in a magnetic field to increase the number of vacancy‐ion pairs. The experiments confirmed the theory, showing that in the current density range 100 –1000 A m−2the local effective diffusion coefficient is proportional to the current density.

ISSN:0021-8979    

DOI:10.1063/1.329809

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Hall measurements on high‐Ohmicn‐type float zone and Czochralski silicon which had received various heat treatments have been carried out as a function of temperature. An anomalous decrease in the Hall coefficient upon cooling was observed for all as‐grown crystals in case the measurements were performed in low magnetic fields (B=0.5 T). In order to investigate the origin of this behavior, both the influence of oxygen and the possibility of a change in the Hall scattering factor were studied. To this end Hall measurements were performed as a function of magnetic field strength up toB=14 T. From the ratio of the low and high magnetic induction limits of the Hall coefficient the Hall scattering factorrhas been obtained. In addition, from the high magnetic induction limit for the Hall coefficient the charge carrier density has been obtained without interference from scattering effects. On the basis of these results the anomalous transport phenomena reported in the literature could be attributed to a change in the Hall scattering factor.

ISSN:0021-8979    

DOI:10.1063/1.329810

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Hydrogenated amorphous silicon obtained by rf sputtering has been annealed using cw lasers (Ar or Kr ion). The annealed films have been microanalyzed for quantitative profiling of hydrogen and argon. TEM analysis was used for structure determination. The release of hydrogen and argon as well as the grain size of the polycrystalline material obtained are related to the deposited laser energy. Comparison with other production methods of such material from the amorphous state is discussed.

ISSN:0021-8979    

DOI:10.1063/1.329811

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The decomposition of CF4and of O2and the formation of the plasma product molecules CO2and COF2have been determined by mass spectrometry for a 2450‐MHz CF4plasma to which variable amounts of oxygen were added. In addition, the SiF4production resulting from the interaction of the plasma effluent with a silicon wafer was monitored. It was found that up to its maximum the decomposition of CF4is twice the amount of decomposed oxygen. This result, combined with those of experiments in which CO2was used instead of oxygen, and experiments in which CF4and O2were discharged separately, leads to the conclusion that after decomposition of O2to O atoms and of CF4to CF3fragments and F atoms, one oxygen atom reacts with one short‐lived CF3fragment to form the primary products COF2and atomic fluorine. At higher oxygen concentrations, excess O(1D) atoms are formed. These atoms rapidly react with the COF2to form CO2and F2. Consequently, the COF2production strongly decreases with the simultaneous formation of carbon dioxide. At these higher oxygen concentrations it is also found that excess molecular oxygen reacts with the atomic fluorine produced, eventually forming molecular fluorine. As a result, the production of SiF4decreases much more strongly than expected on the basis of the decomposition of CF4.

ISSN:0021-8979    

DOI:10.1063/1.329812

出版商:AIP    

年代:1981

数据来源: AIP