摘要:

We present a simple optical technique for measuring features formed in radiation sensitive materials (photoresists) after exposure. The monitoring of photoresist patterns after exposure, but before development is known as latent imaging. Optical techniques used in the past for latent image detection have really only sensed scattered intensity levels from periodic patterns and not spatially resolved images of the features themselves. The application of photon tunneling microscopy to imaging of latent resist patterns exposed using point‐source x‐ray and midultraviolet illumination will be demonstrated. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113400

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A self‐aligning etch method for silicon substrates is presented. A hole pattern is defined on the front side of the silicon substrate while etching of the hole takes place from the back side through the application of a current from the front side of the silicon substrate to a cathode electrode in a solution of HF, HNO3, and H2O. As the etching proceeds, the etched pattern in the back side gradually becomes self‐aligned with the front side pattern of the silicon substrate. Twenty five circular holes arranged in a 5×5 array are formed in a boron‐doped (100) silicon substrate. The etch method provides control over hole dimensions which are 520 &mgr;m in diameter and spaced 520 &mgr;m apart. The self‐aligning property of the etch method enables the formation of different shaped holes. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113401

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Synthesis of ultrafine titania particles is investigated in a diffusion flame aerosol reactor in the presence of a gaseous electric discharge (corona) created by two needle electrodes. The corona wind flattens the flame and reduces the particle residence time at high temperatures, resulting in smaller primary particle sizes and lower level of crystallinity. Increasing the applied potential from 5 to 8 kV reduces the particle size from 50 to 25 nm and the rutile content from 20 to 8 wt %. Coronas provide a clean and simple technique that facilitates gas phase synthesis of nanosized materials with controlled size and crystallinity. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113402

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Thin films of tetrathiafulvanene–tetracyanoquinodimethane (TTF‐TCNQ) grown on mica substrates by vacuum deposition were studied by scanning tunneling microscopy (STM). STM images displayed the usual arrangement of alternative TTF and TCNQ columns aligned parallel to the crystalbaxis. However, in addition to the same phase as that of a TTF‐TCNQ bulk crystal, a new phase is observed. In this new phase the tilt angles the TCNQ and TTF molecular planes make with thea×baxis are different from those observed in the normal phase. This new phase can be explained by the introduction of a stacking fault on the surface. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113403

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We find that a highly double‐oriented film of practically unlimited size can be obtained from a uniaxially drawn film of P(VDF/TrFE) by crystallization in the paraelectric phase with its surfaces free from any constraint other than tensile stress along the chain axis. Thecaxis (the chain axis) and the [110] axis in the orthorhombic system of the poled crystalline film are parallel to the stretching axis and perpendicular to the film plane, respectively. Contrary to conventional crystalline polymer films, the present film has no amorphous region and no lamellar crystal. The film exhibits highly anisotropic characteristics in optical, mechanical, and piezoelectric properties. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113730

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Diamond films have been obtained by the hot‐filament chemical vapor deposition method on a silicon wafer. The substrates were preimplanted by a Si+ion beam (ion energy 25 keV, implantation dosage 2×1017Si/cm2). X‐ray diffraction, scanning electron microscopy, and Raman spectroscopy were used to characterize the structure of the synthesized films. The mechanisms for diamond nucleation on a Si wafer have been discussed. Surface stress is believed to be one of the most important factors for low pressure diamond nucleation on the Si wafer. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113731

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The nucleation of diamond on Si is enhanced for negative substrate bias of 200–250 V. We show that the ion flux is the critical factor causing the enhanced nucleation. The ion energy distribution has a maximum at about 80 eV, the optimum to subplant C ions intoa‐C. We propose that subplantation causes deposition of nanocrystalline graphitic C, and that diamond nucleates where the graphitic planes are locally oriented perpendicular to the surface. An atomic model is proposed that allows a matching of the diamond, graphite, and Si lattice. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113732

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Our preliminary studies show that covalent solid CNxcompounds can be synthesized by high dose nitrogen implantation into carbon thin films. 100 keV N+ions at a dosage of 1.2×1018cm−2were implanted at different temperatures. The samples were evaluated by x‐ray photoelectron spectroscopy (XPS), x‐ray diffraction analysis, and Fourier transform infrared absorption spectroscopy (FTIR). N(1s) core level line XPS analyses show the existence of two different N(1s) bonding states, corresponding to the nitrogen of the C–N covalent bonding state and free state nitrogen, respectively. More importantly, it can be clearly seen that the content of C–N covalent bonding state in the samples is increased with increasing of the implanting temperature of samples. When implantation was performed at 500 °C, C(1s) XPS studies show the existence of three different C(1s) bonding states, corresponding to graphite,i‐carbon, and the carbon of C–N covalent bonding state, respectively, and FTIR analyses indicate that there is an absorption band near 2200 cm−1assigned to the C≡N covalent bonding. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113733

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Scanning tunneling microscopy (STM) studies of monolayer coverage of C60molecules on a 2H–MoS2(0001) surface reveal electronic features on the molecules that are rather different from those observed on metal and other semiconductor surfaces. The STM current contrast of the adsorbed C60is dominated by that of the underlying crystalline lattice at low bias voltages. The observations can be understood by considering (1) a weak adsorption of C60and (2) an electronic correlation effect between the substrate surface and the molecule. All essential aspects of the experimental STM results are quantitatively reproduced by our calculation. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113734

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A general problem in scanning probe microscopy (SPM) of small particles is that the probe itself moves and removes the particles as it tries to image them. This fact has strongly limited the use of SPM in the field of nm‐sized particles, and high‐resolution electron microscopy has been the only alternative for detailed imaging. Here, we take advantage of a moderate sintering at 350 °C to effectively stabilize nanometer‐sized metallic particles on a semiconductor surface, allowing characterization by SPM. Using this technique, we have been able to successfully image aerosol deposited Ag particles of sizes around 35 nm by contact mode atomic force microscopy (AFM). This new sample preparation technique for SPM overcomes the problems of probe‐induced particle movement during scanning and is proposed as a method to ‘‘freeze’’ artificial nanostructures produced by manipulation of particles with the AFM probe. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113735

出版商:AIP    

年代:1995

数据来源: AIP