摘要:

We analyze the importance of self-heating effects in a new cold cathode emitter which consists of a thin region of cadmium sulfide (CdS) sandwiched between a heavily doped indium phosphide (InP) substrate and a low work function lanthanum sulfide (LaS) semimetallic thin film. We identify the mechanisms leading to power dissipation in a cathode with an emission window of rectangular geometry, including the effects of inelastic scattering in the CdS and LaS layers. The latter are modeled using a temperature dependent mean-free path approach. The analysis includes the effects of current crowding in the emission window due to the finite resistivity of the LaS layer. We determine the cathode parameters which minimize current crowding and self-heating effects in the cathode. We also calculate the relative contribution of the ballistic and inelastic portions of the electron current emitted into vacuum.

ISSN:1071-1023    

DOI:10.1116/1.590446

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.590447

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

A sample of low-temperature epitaxial Si grown with five B delta-doped layers 5.4 nm apart has been profiled using secondary ion mass spectrometry under a variety ofO2bombardment conditions. Energies from 400 eV to 1.5 keV were used with angles of incidence from 0° to 70°. Analyses were performed using oxygen flooding of the sample surface during analysis, as well as without using oxygen flooding. The apparent spacing between the B delta layers was used to determine the magnitude and extent of increased sputtering rate at the beginning of an analysis. Changes in depth resolution due to sputter-induced surface roughening are reflected in variations in the apparent width of the B delta layers. It was found that sputtering with 500 eVO2at an angle of 50° while flooding with oxygen produced no measurable change in sputtering rate and resulted in no unexpected shift towards the surface of the B delta layers. These analysis conditions also resulted in a depth resolution which was as good as that obtained using 400 eVO2bombardment at 0° incidence without oxygen flooding. The 0° method of analysis, however, resulted in a 1.1 nm shift of the topmost B delta layer toward the surface, and the 0° method had a sputtering rate only 1/5 that of the 50° method of analysis.

ISSN:1071-1023    

DOI:10.1116/1.590370

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

We report a new Ni/Pt/Au trilayer metallization scheme for the formation of ohmic contact top-GaN.Metal thin films with a thickness of 20 nm for Ni, 30 nm for Pt, and 80 nm for Au were deposited on thep-GaNlayer(Na=9.4×1016 cm−3)by electron beam evaporation. The samples, annealed at 500 °C for 30 s in a rapid thermal anneal system, showed a high quality ohmic contact with a low specific contact resistance of2.1×10−2 Ω cm2.Auger electron spectroscopy analysis of the contact layers suggests that Pt plays an important role in the formation of ohmic contact, indicating that a Ni/Pt/Au trilayer can be used and that it is a promising material system for ohmic contact top-GaN.

ISSN:1071-1023    

DOI:10.1116/1.590448

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

A comparative electron spin resonance (ESR) study was performed on thermal (111)Si/SiO2and (100)Si/SiO2of the vacuum postoxidation-induced interface degradation in terms of interfacial trivalent Si dangling bond creation (ESR-activePb,Pb0,andPb1defects). In (111)Si/SiO2,the degradation mechanism was isolated as pronounced permanentPb(∘Si≡Si3)creation from ∼640 °C onward in densitiesNcmonotonically increasing with anneal temperature; at ∼1100 °C, about1.1×1013Pbs cm−2are created in addition to the as-oxidized state valueNo∼4.9×1012 cm−2.The (100)Si/SiO2interface is found to be much less vulnerable. Only electrically harmlessPb1’s are additionally created, the density reachingNc(Pb1)∼4.4×1012 cm−2at ∼1100 °C. By contrast, the density of the electrically adversePb0trap tends to decrease. Together with the recently established electrical irrelevance ofPb1,the results add to provide a fundamental reason for the preference of the (100) Si face in devicing.

ISSN:1071-1023    

DOI:10.1116/1.590449

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

A custom designed sample handling system which allows the integration of a commercially available scanning tunneling microscope (STM) facility with a commercially available molecular beam epitaxy (MBE) facility is described. No customization of either the STM imaging stage or the MBE is required to implement this design.

ISSN:1071-1023    

DOI:10.1116/1.590496

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

The “Atom Technology” project started in fiscal 1992 as one of MITI’s 10 year projects, aims at systematically establishing technology for handling individual atoms and molecules on a solid surface or in a three-dimensional space, as a generic technology for various fields of industry. This project, closely adjacent to science, emphasizes the following three key focuses: atom manipulation, nanoscale self-organization, and critical-state phase control, with two basic approaches ofin situdynamical observation (experimental) as well asab initiocalculation (theoretical). In this article, several topics were picked up from recent activities at the Joint Research Center for Atom Technology (JRCAT) for Phase I of the initial 6 years (1992–1997) and some technical details were described: (1) ultrathinSiO2on Si(001) surfaces; layer-by-layer oxidation, its kinetics, scanning reflection electron microscopy observation, and scanning tunneling microscopy observation of leakage sites; (2) growth and transport of structure-controlledSinHx+clusters for deposition using a novel ion trap; and (3) colossal magnetoresistance and related phenomena in perovskite-type manganese oxides. Research plans for phase II (1998–2001) of the project will be also touched upon.

ISSN:1071-1023    

DOI:10.1116/1.590450

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Biological cells are strongly influenced by the topography of the surface on which they live, both in cell culture and in an animal. They are guided along micron sized grooves and change their shape becoming more elongated. On the other hand, cells do not adhere to surfaces that are covered in small nanometrically sized pillars. These effects can be used for cellular engineering purposes to determine the behavior of cells and in particular to make prostheses for medical purposes. The differences in micro and nanofabrication techniques necessary to adapt normal semiconductor technology for these purposes are discussed. Patterning of plastics using mechanical methods (embossing and molding) is shown to have excellent resolution, can be used on biodegradable material and a large enough area of patterned material can be produced at a reasonable cost. An application of this technology to the repair of broken tendons is discussed in some detail. It is shown that a biodegradable membrane patterned by embossing with a fused silica master can be used to effect tendon repair. Not only does the tendon reheal, but the synovial channel that should surround the tendon and provide lubrication to the tendon, is reformed correctly.

ISSN:1071-1023    

DOI:10.1116/1.590451

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

X-ray lithography (XRL) is a very promising technique with the potential to be available for integrated circuit manufacturing as early as the 130 nm generation. As a result of many years of development, the technology is relatively mature. Synchrotron sources have demonstrated performance and reliability; preproduction aligners are available from multiple vendors; significant improvements are being made in mask fabrication; and high resolution imaging has been demonstrated at 100 nm and below. Established vendors already have experience with almost all of the tools that are needed, although improved performance is required for most in order to satisfy the error budgets at 130 nm and below. Significant development activities are continuing in both the United States and Japan, and numerous complex integrated circuits have been fabricated using XRL for one or more critical levels. Nonetheless, there are challenges still to be met. Among the most important are the development and commercial availability of an improvede-beam mask writer; the ability to fabricate defect-free masks satisfying the image placement and critical dimension control requirements with good yields; the stability of the masks in usage (including the issue of possible radiation damage); the ability to correct for magnification errors; and the ability to satisfy the industry’s desire for a technology extendible to 70 nm ground rules. These issues are primarily manufacturing issues, as opposed to issues related to demonstrating proof-of-concept or feasibility, although demonstrating extendibility is still needed before the industry can commit to using XRL at 70 nm ground rules. Because of the existing XRL facilities and experience, effective work to address these and other issues can be accomplished in a timely manner.

ISSN:1071-1023    

DOI:10.1116/1.590452

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

An extreme ultraviolet (EUV) lithography tool using 13.4 nm radiation is being developed by a consortium of integrated circuit (IC) manufacturers to support 100 nm imaging for integrated circuit production. The 4×, 0.1 NA alpha tool has a>1 μm depth of focus, all reflective optics, a xenon laser plasma source, and robust reflective masks. The technology is expected to support feature scaling down to 30 nm.

ISSN:1071-1023    

DOI:10.1116/1.590453

出版商:American Vacuum Society    

年代:1998

数据来源: AIP