摘要:

Boron depth profiles in low‐energy BF+2‐implanted silicon were measured using laser‐ionization sputtered neutral mass spectrometry and secondary‐ion mass spectrometry. The laser‐ionization sputtered neutral mass spectrometry measurements provided more accurate boron profiles in the ultrashallow regions (below 20 nm) than the secondary‐ion mass spectrometry measurements. A pileup of boron atoms in the region below 5 nm after annealing was revealed by laser‐ionization sputtered neutral mass spectrometry.

ISSN:0734-211X    

DOI:10.1116/1.588711

出版商:American Vacuum Society    

年代:1996

数据来源: AIP

摘要:

The Ar+‐sputter‐induced ‘‘cone evolution’’ on Mo‐seeded Cu is known to entail the growth of hillocklike crystallites on the cone surface. Such crystallites have now been identified as Cu, by means of high‐resolution energy dispersive x‐ray analysis. The Cu crystallites grew selectively on the Mo lattice of seed layers, and sometimes at the seed‐layer apex which suffered from head‐on ion impact during sputtering. The crystallite growth was thus not a direct consequence of ion impact, leading to a hypothesis that a viscous overlayer of Cu on the growing Mo lattice condensed into dewdroplike crystallites upon switching off the ion beam.

ISSN:0734-211X    

DOI:10.1116/1.588712

出版商:American Vacuum Society    

年代:1996

数据来源: AIP

摘要:

Deposition rates, wet etch rates, and thickness uniformity experiments were performed using O3/TEOS thermal chemical‐vapor deposition. Our results for oxide deposition show optimum process window around 200 Torr for producing films of good quality (uniformity and material properties). This is in excellent agreement with the modeling predictions over a broad range of pressure (100–600 Torr) and temperature (370–470 °C). The model invokes both gas phase and surface reaction mechanisms. The former is needed to produce deposition precursors and leads to an observed increase‐maximum‐decrease dependence on the deposition pressure; this decrease is associated with a competing (parasitic) role of gas phase reactions. Our experiments identify particle formation at higher pressures which is consistent with the expected dual role of gas phase reaction in generating (1) required deposition precursors and (2) particulates in the gas phase under some conditions.

ISSN:0734-211X    

DOI:10.1116/1.588713

出版商:American Vacuum Society    

年代:1996

数据来源: AIP

摘要:

We are developing a sensor capable of detecting biological species such as cells, proteins, toxins, and DNA at concentrations as low as 10−18M. The force amplified biological sensor will take advantage of the high sensitivity of force microscope cantilevers to detect the presence of as little as one superparamagnetic particle bound to a cantilever by a sandwich immunoassay technique. The device, which will ultimately be small enough for hand‐held use, will perform an assay in about 10 min. Lock‐in detection and use of a reference cantilever will provide a high degree of vibration immunity. An array of ten or more cantilevers will provide greater sensitivity and the capability to detect multiple species simultaneously. The force amplified biological sensor also offers the potential of distinguishing and studying chemical species via its ability to measure binding forces.

ISSN:0734-211X    

DOI:10.1116/1.588714

出版商:American Vacuum Society    

年代:1996

数据来源: AIP

摘要:

By adapting a scanning force microscope to operate at frequencies above the highest tip–sample resonance, the sensitivity of the microscope to materials’ properties is greatly enhanced. The cantilever’s behavior in response to high‐frequency excitation from a transducer underneath the sample is fundamentally different than to its low‐frequency response. In this article, the motivations, instrumentation, theory, and first results for this technique are described.

ISSN:0734-211X    

DOI:10.1116/1.588715

出版商:American Vacuum Society    

年代:1996

数据来源: AIP

摘要:

We have used a scanning near‐field optical microscope to investigate the optical properties of a thin organic film consisting of poly(phenylene vinylene) and tris(8‐hydroxy)quinoline aluminum. Near‐field optical images taken in transmission mode using a 488 nm laser light revealed numerous ‘‘dark spots’’ scattered randomly across the film; however, the dark spots were not related to the surface topography. These dark spots ranged in size from 100–300 nm in diameter. The nature of the dark spots was attributed to an increase in the absorption at 488 nm as a result of local variations in the poly(phenylene vinylene) film.

ISSN:0734-211X    

DOI:10.1116/1.588716

出版商:American Vacuum Society    

年代:1996

数据来源: AIP

摘要:

A semimicroscopic approach based on linear response theory is applied to analysis of the near‐field‐reading process, both for an isolated recording bit and for bits periodically arranged by means of photon scanning tunneling microscopy (PSTM). The polarization effects and typical characteristics of super‐resolution are shown by simulation. The results are valid not only for the read‐out process in optical storage, but also for sensing of local indices of refraction or absorption in samples observed with PSTM, in general. Some theoretical results are compared with experimental data in terms of the resolving power.

ISSN:0734-211X    

DOI:10.1116/1.588717

出版商:American Vacuum Society    

年代:1996

数据来源: AIP

摘要:

A combined noncontact shear force and scanning near‐field optical microscope has been used to study the structure of a spherulitic polyhydroxybutyrate specimen. Using polarized light, the birefringence structure of the spherulite revealed a concentric ring structure with submicron resolution. Optical images could be correlated with the topographic images, recorded simultaneously, of the same area. This demonstrated directly the correlation between the twisting structure of the ribbonlike polymer crystallites and the birefringent concentric ring structure, and demonstrates the capability of scanning near‐field optical microscopy for studying molecular orientation as a function of topographic structure.

ISSN:0734-211X    

DOI:10.1116/1.588718

出版商:American Vacuum Society    

年代:1996

数据来源: AIP

摘要:

A scanning near‐field optical microscope combined with an atomic force microscope is described. The instrument uses a microfabricated force‐sensing cantilever made of single‐crystal silicon with an integratedp‐ndiode at its end as a microphotodetector. The photosensitive cantilever efficiently detects the light scattered by the tip in the evanescent field generated by illuminating the sample by total internal reflection. Simultaneously the surface force is detected by monitoring the deflection of the cantilever. Both scanning near‐field optical microscope and atomic force microscope images of a compact disk grating and a photosynthetic protein membrane were obtained. The membrane was deposited on the glass substrate using the Langmuir–Blodgett technique. The features in the scanning near‐field optical microscope images are similar to those in the atomic force microscope. The possible crosstalk between the optical and the topography signal is discussed.

ISSN:0734-211X    

DOI:10.1116/1.588719

出版商:American Vacuum Society    

年代:1996

数据来源: AIP

摘要:

Recently, the use of an atomic force microscope silicon‐nitride tip as a scanning near‐field optical microscope probe to collect the optical near field close to a surface, has been successfully demonstrated. However, several questions about such a setup are still unanswered: the influences of the surface topography and the polarization of light on the imaging process are not clearly understood; the scattering cross sections of the reflected and transmitted light are not accurately estimated. With the aim of clarifying these questions, in this article we propose numerical simulations performed on a two‐dimensional model of a SiN tip within the framework of the Green’s function technique. The treatment provides precise calculations of the near and far fields by exploiting an iterative numerical scheme based on the parallel use of the Lippman–Schwinger and Dyson’s equations. A remarkable result demonstrates that a branch of the SiN tip acts as an optical waveguide. Consequently, a significant amount of light is scattered in directions where scanning near‐field optical microscope setups using SiN tips do not detect. A modification of the experimental configuration leading to the detection of this signal is suggested.

ISSN:0734-211X    

DOI:10.1116/1.588720

出版商:American Vacuum Society    

年代:1996

数据来源: AIP