摘要:

A scanning thermal microscope has been developed which is capable of imaging thermal properties of materials with high spatial resolution. First results indicate a lateral resolution less than 200 nm. The microscope employs a miniaturized thermal probe whose tip is formed as a thermocouple. The probe is laser heated to generate a thermovoltage. A sample approaching the heated tip leads to a heat flow from the tip to the cooler sample surface and thus to a decrease of the measured voltage. In the initial experiments we scanned the tip above the sample surface with open feedback loop and mapped the thermovoltage at each location of the scan range. Furthermore, we closed the feedback loop keeping the thermovoltage constant and measured thezdisplacement of the piezoelectric tube carrying the probe. All these measurements yield topographical as well as thermal information of the sample surface.

ISSN:0734-211X    

DOI:10.1116/1.588094

出版商:American Vacuum Society    

年代:1995

数据来源: AIP

摘要:

Nanocrystalline GeFe samples with Fe concentration varying from a few percent to about 86% were synthesized using an inert gas condensation method. The samples were compressed into thin disks in vacuum before exposure to air. Magnetization measurements found that the magnetization of the samples cannot be described by a simple Langevin function. Atomic force microscopy has been used to characterize the average size of the nanocrystals in the samples. For samples with a low concentration of Fe, atomic force microscopy images show distinct individual clusters with an average size of about 500 Å in diameter. For samples with a higher concentration of Fe, individual clusters cannot be distinguished, and atomic force microscope images show a mountain‐like, rugged morphology on the sample surfaces.

ISSN:0734-211X    

DOI:10.1116/1.588095

出版商:American Vacuum Society    

年代:1995

数据来源: AIP

摘要:

Co nucleation and growth on graphite were studied by scanning tunneling microscopy. Co atoms were found to adsorb preferentially on theBsites. Two‐ and three‐dimensional Co clusters were observed, distributed uniformly on the graphite surface. The internal structure of the Co cluster is quite disordered. Cluster evolution on the surface was observed in sequential images, suggesting that atom dissociation and incorporation may be one of the mechanisms for cluster migration. Co cluster‐induced superstructures were observed to localize around the clusters on the surface. The patterns of some superstructures reflect graphite’s threefold symmetry. Thermal annealing of the sample resulted in Co‐promoted etching of the graphite surface.

ISSN:0734-211X    

DOI:10.1116/1.588096

出版商:American Vacuum Society    

年代:1995

数据来源: AIP

摘要:

A process for fabricating thin Si nanowires is proposed which can reduce the parasitic series resistance of the nanowire. The process includes electron cyclotron resonance plasma deposition of a SiO2film through the openings of a patterned resist film. Since the SiO2thickness decreases as the opening narrows, the SiO2film can be made thinnest in the nanowire region. Therefore, during the following reactive‐ion etching, the SiO2film in this region is removed first and the Si layer is then selectively etched. A Si nanowire fabricated through this process shows quantized conductance at temperatures as high as 200 K.

ISSN:0734-211X    

DOI:10.1116/1.588097

出版商:American Vacuum Society    

年代:1995

数据来源: AIP

摘要:

A new image reversal process has been developed for Si nanodevice fabrication that uses electron beam lithography and electron cyclotron resonance (ECR) plasma techniques. This process is based on Si oxidation with an ECR oxygen plasma through the openings in resist mask patterns. Si on SiO2is selectively etched by either Cl2‐based ECR plasma etching or KOH anisotropic etching by using a plasma oxide mask. ECR plasma formed silicon oxide with a thickness of 2–3 nm was found to be an excellent etch mask for these etching techniques. Highly directional ECR oxygen plasma keeps the change in the resist linewidth and edge roughness small enough for nanofabrication. Furthermore, the linewidth of reversed Si patterns can be reduced by SF6addition to Cl2in ECR plasma etching. This image reversal process successfully achieves 10‐nm‐scale Si wires and pillars.

ISSN:0734-211X    

DOI:10.1116/1.588098

出版商:American Vacuum Society    

年代:1995

数据来源: AIP

摘要:

Synchrotron radiation‐excited etching of Si, SiC, and WO3has been investigated using a noncontact mask with a pattern of submicrometer scale. The blank pattern of the mask was replicated on the etched surface, and highly area‐selective etching was realized at the size of ∼0.4 μm. The spatial distribution of synchrotron radiation intensity on the sample determined the depth profile of the etched region of the sample. Some adsorbate which might be redeposited etching products appeared in the vicinity of the blank pattern of the mask.

ISSN:0734-211X    

DOI:10.1116/1.588099

出版商:American Vacuum Society    

年代:1995

数据来源: AIP

摘要:

A plasma developing process for photosensitive polyimide layers has been investigated as an alternative to wet development. Silylation of photoimageable polyimide by applying an organosilicon compound and subsequent ultraviolet exposure using ag‐line mask aligner equipment lead, as a consequence, to copolymerization of photoactive functional groups of silylating agents and sensitizer groups of the polyimide‐based photoresists. Development of the photoresist layer is carried out by means of oxygen‐containing plasma. Interaction of oxygen plasma with a silylated surface of polyimide leads to the formation of a silicon oxide layer that acts as a barrier giving large differences in the etching rates of the photoresist covered and not covered with organosilane. The influence of O2plasma etching process parameters on the etching selectivity is studied. The photochemical silylation process and the dry developing method have been characterized by scanning electron microscopy and Fourier transform infrared spectroscopy.

ISSN:0734-211X    

DOI:10.1116/1.588100

出版商:American Vacuum Society    

年代:1995

数据来源: AIP

摘要:

Photocathode electron projection is an electron lithography technique that may be used to pattern semiconductors at the deep submicron level. Using a robust gold cathode, mask features in the range of 0.11–0.54 μm have been transferred to electron resist coated wafers with adequate depth of focus (≂5 μm) and large field of view (≂2 cm2). Low accelerating voltages ∼3 keV minimize proximity effects, and with a mask to wafer spacing of a few millimeters, the necessary magnetic field is ≂0.46 T.

ISSN:0734-211X    

DOI:10.1116/1.588101

出版商:American Vacuum Society    

年代:1995

数据来源: AIP

摘要:

The patterning and modification of organosilane self‐assembled monolayers on Si native oxide surfaces by low‐ and high‐energy ion beams were investigated. The nature and extent of low‐energy (50–140 eV) Ar+ion‐induced modification of a 2‐(trimethoxysilyl) ethyl‐2‐pyridine monolayer was studied by x‐ray photoelectron spectroscopy and by the quality of the electroless Ni patterns obtained. C(1s) and N(1s) core level x‐ray photoelectron spectroscopy indicated that the ion‐induced modification of the monolayer involved loss of the ethylpyridyl chain by sputtering and/or decomposition. The type of modification was independent of the ion energy and fluence, but the extent of modification depended on both parameters. The modification of the pyridine monolayer was monitored by the percent loss in the N(1s) peak area; modification commenced at a fluence of 5×1014ions/cm2and was observed for all ion energies studied. However, selective electroless metallization occurred only for monolayers that suffered ≳50% loss in the N(1s) x‐ray photoelectron spectroscopy signal. A damage saturation level of 80% N(1s) loss was indicated at an ion fluence of 9×1015ions/cm2. A high‐energy focused ion beam lithography system was also used to evaluate the high resolution patterning ofN‐(2‐aminoethyl)‐3‐aminopropyltrimethoxysilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, and pyridine monolayers by Ga+, Si++, Au+, and Au++ions at energies ranging from 50 to 280 keV. The highest resolution metal features obtained were 0.3‐μm‐wide gaps on phenethyltrimethoxysilane and pyridine monolayers using Ga+and Si++ions. Aminopropyltrimethoxysilane monolayers were found to require ten times higher ion fluences to achieve comparable results with the phenethyltrimethoxysilane and pyridine monolayers for all ions investigated.

ISSN:0734-211X    

DOI:10.1116/1.588102

出版商:American Vacuum Society    

年代:1995

数据来源: AIP

摘要:

The etching contamination remaining in Al‐base SiO2contact holes after hole fabrication followed by a series of cleaning treatments was analyzed by using thermal desorption spectroscopy. The hole aspect ratio dependence was measured for fluorinated aluminum molecules, the major desorption species. The amount of contaminant material in the holes was found to increase with the sidewall area of the holes, suggesting that the contaminant material desorbs from the bottom surface and accumulates on the SiO2sidewall during contact hole etching.

ISSN:0734-211X    

DOI:10.1116/1.588103

出版商:American Vacuum Society    

年代:1995

数据来源: AIP