摘要:

A new scanning probe microscopy has been developed which directly measures carrier scattering in materials and at interfaces. This energy‐resolved spectroscopy of carrier‐carrier scattering is applicable to both electron and hole scattering in bulk materials and in complex structures. This paper describes the unique experimental technique and reviews a fundamental theoretical treatment which is in excellent agreement with the experimental results.

ISSN:0094-243X    

DOI:10.1063/1.41424

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Two different approaches to study the interaction of light with the electronic tunneling in a Scanning Tunneling Microscope (STM) will be discussed. If the surface of the semiconducting WSe2is irradiated with visible light a surface photovoltage and a corresponding photocurrent can be observed. To investigate this effect the influence of light on the I‐V spectroscopy and the wavelength dependence of the photocurrent have been analyzed. The effect of the surface plasmons excited in a thin silver film on the tunneling process has been studied. The surface plasmons provide a very efficient coupling of the incoming light to the tunneling gap. The detection of the surface plasmons is due to the rectification of the optical ac‐field.

ISSN:0094-243X    

DOI:10.1063/1.41425

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We discuss recent progress in the investigation of photon emission processes occurring in the tip‐surface region of the STM. Through the use of selected examples recorded on metals and semiconductors some interesting aspects of this area of research are presented. In particular, radiative plasmon modes on metals specific to the STM geometry and their excitation by inelastic tunneling are compared to luminescence processes in semiconductors. The ability to fabricate nanostructures on Cu and investigate their photon emission characteristics with atomic resolution is included to give a feeling for the frontier aspect of this research.

ISSN:0094-243X    

DOI:10.1063/1.41426

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The Scanning Capacitance Microscope has been used to profile insulating, semiconducting and conducting surfaces with resolution down to 25 nanometers. In the case of semiconducting materials, it has been demonstrated that lateral dopant profiling can be achieved with 100 nanometer spatial resolution‐well beyond that which can be achieved by conventional techniques. Measurements on semiconductors indicate that the technique should be useful for device characterization. In this paper, we review the basis of Scanning Capacitance Microscopy and present some of the more recent results.

ISSN:0094-243X    

DOI:10.1063/1.41427

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Innovations in semiconductor technology have provided us with an opportunity to examine devices with vertical and lateral dimensions less than 100 nanometers‐comparable to the wavelength of the electron at the Fermi energy. Here we review the relationship of energy quantization, phase coherence and impurity scattering to the low temperature resistance of discrete devices comparable in size to the electron wavelength, and discuss implications for electrical isolation between such devices.

ISSN:0094-243X    

DOI:10.1063/1.41383

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

This paper is a review of the research work of the Yoshida Nano‐Mechanism Project which recently concluded its 5 year activity. The project was organized into three different research groups. The basic analysis group worked on development of scanning tunneling microscopes and their applications to processed surfaces and biological materials, and on making zone plates more efficient for X‐ray microscopy. The measurement and control group concentrated its research on displacement measurements and positioning devices. Finally, the processing group studied multilayers for X‐ray mirrors and ion beam processing for the production of super smooth surfaces.

ISSN:0094-243X    

DOI:10.1063/1.41384

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Nanometrology is defined here as the science of measuring the dimensions of objects or object features to uncertainties of one nanometer or less. Four major tasks of nanometrology are examined: realizing a metric in the measurement space; establishing the metric in a coordinate reference frame; generating and measuring repeatable motion relative to the coordinate reference frame; and linking the testpiece to the coordinate reference frame/metric by a probe. Optical scales, x‐ray interferometry, heterodyne interferometry, Fabry–Perot etalons, impedance‐based transducers, and STM scales are evaluated as possible means to realize a metric. The major error sources, practical limitations, and guidelines for establishing a coordinate reference frame are described. The repeatability of sliding bearings and flexure bearings is examined and this combined with cosine and Abbe´ offset errors is used to estimate uncertainties in generating and measuring linear motion. Finally, the effects of probe geometry, probe interaction lengths, probe forces and probe energies on lengths measurements are discussed. The paper concludes with estimates of an overall uncertainty for dimensional measurements of objects or object features up to 50 mm×50 mm in size when using optical microscopes, electron microscopes, and STMs as probes.

ISSN:0094-243X    

DOI:10.1063/1.41385

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

This paper describes recent studies ofe‐beam sensitive resist materials with a vacuum Scanning Tunneling Microscope (STM). Research has concentrated on negativee‐beam resists and the comparison of lithographic patterns written at low voltages (5–50 V) with the STM and high voltages (50 kV). Two resist materials have been studied. The first is a polydiacetylene (P4BCMU) which was developed at the Naval Research Laboratory. The second is SAL‐601‐ER7 commercially available from the Shipley Company. Both are state of the art in terms of resolution for negative resists at 50 kV and have a sensitivity similar to the high resolution positive resist polymethylmethacrylate (PMMA). In both cases significantly smaller features could be written in the STM than at 50 kV. The high voltage written features were significantly greater in size than expected on the basis of electron scattering (and can be written in PMMA). These results are discussed in terms of the insights gained into the resolution defining processes for the resists. In describing the use of the STM as a lithographic tool, two main points will be made. First, the STM can be used to lithographically define patterns in a resist. Second, the STM provides a unique way to study the exposure mechanisms in resist materials.

ISSN:0094-243X    

DOI:10.1063/1.41387

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A novel concept based on STM aligned field emission (SAFE) with microlens to form an exceptionally high brightness electron source and low aberration electron probe forming system has been explored. Electron optical studies of such a microsource have shown it to have a brightness two to three orders of magnitude greater than conventional field emission sources at energies in the low keV range and the ability to form an ultra‐high resolution probe with diameter in the 1 to 10 nm range in conjunction with additional microlenses. Encouraging preliminary experimental results have been obtained.

ISSN:0094-243X    

DOI:10.1063/1.41388

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We present an analysis of the impact of space charge effects on the performance of a proposed scanning tunneling microscope (STM) microlens with magnetic focusing.1We compare analytical and numerical estimates of energy broadening, and consider scaling of the energy broadening with magnetic field. We find relative energy spreads of 10−4to 10−3at 0.1 &mgr;A current, and 10−3to 10−2at 1 &mgr;A, implying that space charge‐induced energy broadening will not become significant compared to other sources until the current exceeds several &mgr;A. It is observed that space charge effects decrease with increasing magnetic field. For typical operating values, the space charge contribution to the beam diameter should range from 1–100 A˚.

ISSN:0094-243X    

DOI:10.1063/1.41389

出版商:AIP    

年代:1991

数据来源: AIP