摘要:

We present results of the fabrication and investigation of totally spatially localized crystalline structures. Low temperature photoluminescence exhibits structure that is best explained by a bottleneck for hole energy loss. This bottleneck is believed to be a direct consequence of the modification of the band structure by the fabrication‐imposed potential and is believed to be the first evidence for total spatial quantization in a fabricated heterojunction system.

ISSN:1071-1023    

DOI:10.1116/1.583331

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

AlF3evaporated thin films of 20–80 nm thickness have been used as self‐developing positive resists and also as negative resists forming metallic Al structures. The exposure mechanism of AlF3resist has been investigated, and nanometer scale features have been fabricated in both cases at exposure doses of about 20 C/cm2and 2 C/cm2at 100 keV, respectively. Using reactive ion etching, AlF3resist patterns have been transferred into Si3N4, resulting in feature sizes as small as 20 nm.

ISSN:1071-1023    

DOI:10.1116/1.583332

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Two new types of Si metal‐oxide‐semiconductor field‐effect transistor (MOSFET) devices have been fabricated and tested which involve a dual gate structure, the lower one being a W grating of 0.2 μm period, 0.1 μm linewidth. These devices, the lateral surface superlattice and the quasi‐one‐dimensional device, explore the regime where quantum mechanical effects become important. Fabrication techniques are described and projections made with regard to lithographic techniques for future electronic systems based on sub‐100 nm linewidth devices. X‐ray lithography at λ∼1 nm can provide linewidth control ≲10 nm and high pixel‐transfer rate. The mask‐to‐substrate gap is constrained by diffraction. However, with a resist of sufficiently high contrast (and low sensitivity to avoid edge raggedness) linewidths of 50 nm should be feasible in high volume production at mask–substrate gaps of a few μm.

ISSN:1071-1023    

DOI:10.1116/1.583333

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

A new class of microstructures, such as the opposed gate–source transistor, requires the careful alignment of submicron features on two opposite surfaces of a substrate. Concepts for self‐aligned methods for accomplishing dual‐surface lithography have been explored for the first time. Self‐alignment is based on the integration of the exposure mask into the microstructure and subsequent exposure through the substrate. Electrons, ions, and x rays have been explored for exposing lines as narrow as 200 nm. Both theoretical Monte Carlo results and experimental data on fabricated structures are given. Self‐aligned dual‐surface lines with a width of 200 nm have been demonstrated across a 3‐μm‐thick silicon membrane. Ion, electron, and x‐ray exposure through the substrate limits the thickness of the membrane to about 100 nm, 1 μm, and 10 μm, respectively for reasonable particle energies and submicron resolution.

ISSN:1071-1023    

DOI:10.1116/1.583334

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

The base region ofNPNtransistors was fabricated using a 0.2 μm beam diameter (maskless) of 75 keV B focused ion beam (FIB), and on the same wafer a broad beam (with mask) of 75 keV B ions with conventional ion implantation. Transistor properties were compared using electrical characteristics, microbeam Rutherford backscattering spectroscopy (RBS), and scanning Auger microscopy (SAM). No significant differences were found between the transistors fabricated with FIB and with conventional ion implantation. Lateral doping profiles were implanted using the FIB system. Bipolar transistors with lateral active base profiles implanted with FIB were shown to have normal device characteristics. While the main intent was to assess the feasibility of fabricating the devices, the expected relationships between lateral profile and base resistance and current gain were observed. The results indicate that FIB can be used to study the impact of lateral profiles on device performance.

ISSN:1071-1023    

DOI:10.1116/1.583335

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

The fabrication of multiterminal silicon MOSFET’s containing channel segments as narrow as 30 nm is described. These can be used for a variety of fundamental studies of quantum transport. In particular, in 100‐nm channels, spatially localized voltage measurements can be made probing the scattering effects of a single electron trap.

ISSN:1071-1023    

DOI:10.1116/1.583337

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Clear evidence of Aharonov–Bohm oscillations with respect to the flux quantum Φ0=h/ehas been observed in the magnetoresistance of single, submicron diameter, normal metal rings. The rings were fabricated using contamination nanolithography in a personal computer controlled, high resolution, scanning transmission electron microscope. The magnetoresistance oscillations developed belowT≂1 K, and, surprisingly, persisted without attenuation for more than 1000 periods.

ISSN:1071-1023    

DOI:10.1116/1.583338

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Molecular parameters and lithographic performances evaluated with a 20 kV electron beam of a newly developed negative resist, chloromethylated poly‐2‐isopropenylnaphthalene (CM‐IPN), are presented. IPN polymers with narrow molecular weight distribution (MWD) were obtained by anionic polymerization. Subsequent chloromethylation can enhance sensitivity with slight broadening of MWD. Observed contrast (γ) values of ∼2 are almost independent of sensitivity. The reactivity evaluated asMw ⋅ D0(Mw, molecular weight;D0, gelation dose) is about 0.18. Linewidth patterns of 0.1 μm or less with an aspect ratio of 5 can be delineated. High dry‐etching durability and excellent thermal stability owing to aromatic rings and the high glass transition temperature (230 °C) are also confirmed.

ISSN:1071-1023    

DOI:10.1116/1.583339

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Polyimide is characterized as a negative electron resist with an average contrast of 2.1. Crossovers in which continuous metallic lines are deposited over polyimide bridges (patterned by e‐beam lithography) have been fabricated. The leakage current through the polymer is negligible for potentials as high as 70 V applied between the crossovers and underlying contacts. A process for fabricating metal on polymer (MOP) ion implantation masks, using only organic solvents, is described. These masks are shown to be more reliable than those fabricated using oxygen plasma etching, as they are easier to remove completely after ion implantation.

ISSN:1071-1023    

DOI:10.1116/1.583340

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Optical resists have been optimized for e‐beam direct writing in order to enhance process compatibility. Drawbacks of optical positive resist (such as AZ‐2400) for e‐beam application are the following: (1) It is readily converted to a negative image when exposed to the high doses required for fiducial mask detection (multiple scans over a localized region), and (2) this negatively converted region is difficult to remove. The ratioDgi/Dpis proposed as a measure of rating positive resists for ease of conversion. As this ratio becomes larger, the likelihood of forming a negative image in the resist becomes smaller. The values for AZ‐2400 and RE‐5000p were 15 and 40, respectively. Conversion mechanisms were examined and two important factors were found: (1) The sensitizer contribution to negative image conversion was small, and (2) methylene group density in novolak was a dominant factor. Considering the above factors, a new positive novolak e‐beam resist PER‐1 has been developed with aDgi/Dpratio of 285. Quarter‐micron patterns are easily delineated in PER‐1 with a variable‐shaped e‐beam system.

ISSN:1071-1023    

DOI:10.1116/1.583341

出版商:American Vacuum Society    

年代:1986

数据来源: AIP