摘要:

Etching experiments have been conducted on phosphorus doped Si 〈100〉 samples in low pressure SF6/Ar microwave multipolar plasmas which have been characterized. The influence of SF6partial pressure on anisotropy has been determined. Strictly anisotropic etching of silicon was obtained under SF6pressure of about 3×10−4Torr in an SF6/Ar gas mixture, the total pressure being (3–5)×10−3Torr. An etching rate of ∼150 nm/min, without any undercutting, has been achieved under low energy ion impact. The anisotropic etching mechanisms involved in the SF6/Ar system are discussed.

ISSN:0734-211X    

DOI:10.1116/1.583437

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Optical emission intensities from CF4+O2plasmas are measured at various positions in a rf parallel plate reactor. Since the emission intensities are measured at two different positions between the anode and the cathode electrodes simultaneously, the intensity at either position can be used as a reference to check fluctuations of plasma conditions. Though the raw measured emission intensities depend strongly on the position, the emission intensities normalized to Ar emission vary less than 15%. Although the generation rates of plasma species may depend on the position, the spatial distributions of the plasma species densities are nearly uniform because of diffusion. However, effects of the generation rate and/or the gas flow must also be considered when the spatial dependencies of the plasma species are examined in detail.

ISSN:0734-211X    

DOI:10.1116/1.583354

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Masked ion beam lithography (MIBL) is capable of high resolution (<50 nm) proximity printing with short exposure times (<1 s). In this letter we demonstrate the large process latitude and precise linewidth control possible with MIBL when stencil masks are employed. Features, 0.65 μm in dimension, exposed in polymethylmethacrylate (PMMA) show negligible linewidth variation (<50 nm) for a change in dose of over an order of magnitude. This linewidth control is a result of the high contrast of stencil masks, the low divergence of the ion beam, lack of diffraction, and small proximity effect of this technology. The linewidth control of MIBL is compared to the linewidth control of optical projection lithography and x‐ray lithography.

ISSN:0734-211X    

DOI:10.1116/1.583358

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

The mechanism of overhang formation in a diazide/novolak photoresist film by the chlorobenzene soak process for lift‐off stencil fabrication is investigated by gel permeation chromatography. The experimental results show that overhang profile formation is controlled mainly by the removal of photoactive compounds (PAC’s) from a resist film. The amount of PAC loss within the modified region in a resist film must be precisely controlled to form a desired overhang profile. The amount of PAC loss depends mainly upon the molecular weight of the PAC’s and the kind of soaking solvent used.

ISSN:0734-211X    

DOI:10.1116/1.583370

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Surface morphologies of the molecular beam epitaxy (MBE)‐grown GaAs layers using background arsenic‐pressure‐control method were investigated. The growth parameters, such as substrate temperatures, growth rates, epilayer thicknesses, As/Ga ratios, doping concentrations, substrate types, etc., are related to the observed oval defect density. Protrusions and Ga‐droplet induced oval defects were formed during growth. The origin of the oval defects in our system is found to be the gallium oxide, not Ga ‘‘splitting’’ from the effusion cell. Surface preparations are also another important factor in reducing the oval defect density. Special triangular pyramidal defects with concave or acute top surfaces were found. They have the same major axis as oval defects. Also found were defects with perpendicular orientation to the oval defects. Such defects are attributed to contaminations on the surface and can be eliminated.

ISSN:0734-211X    

DOI:10.1116/1.583319

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

The relationship between the conduction band discontinuity (ΔEc) and the band gap difference (ΔEg) of InGaAsP/InP heterojunctions is measured for the first time using capacitance–voltage analysis. It is found that ΔEc=(0.39±0.01)ΔEgover the entire spectrum of compositions of InGaAsP lattice matched to InP. This result is to be contrasted with those obtained for the GaAs/GaAlAs material system, where 60%–70% of the band gap difference between a particular composition of GaAlAs and GaAs appears in the conduction band. The measurements discussed in this work were made using novel organic‐on‐inorganic contact barrier devices. Due to the high energy barriers between certain organic materials and InGaAsP, high resolution measurements of the carrier concentrations, layer thicknesses, conduction band discontinuities, and other relevant parameters were made possible. Constructing wafer contour maps of the fixed charge density at the heterointerface (σ) using this technique indicated no systematic dependence of ΔEcon σ for σ<5×10 cm−2, as expected.

ISSN:0734-211X    

DOI:10.1116/1.583336

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

ISSN:0734-211X    

DOI:10.1116/1.583350

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Recent proposals for neural network models indicate that an array of amplifiers coupled to a lattice of wires with resistive components at the crosspoints can perform calculations using collective properties similar to those observed in biological systems. Such a network can perform both memory and processing functions. The promise of the connection matrix processor lies in its very high density, fault tolerance, and massively parallel operation. This paper describes the operation of a neural network and exploratory fabrication techniques for its implementation.

ISSN:0734-211X    

DOI:10.1116/1.583351

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

The production of VHSIC and microwave devices has shown that submicron lithography by e‐beam, optical, or x‐ray systems is rapidly becoming feasible. There is, however, a demand developing for a nanolithography tool for producing GaAs devices and for investigating the physics of scaling of silicon semiconductor devices. We have developed an electron beam lithography system, the JBX‐5D II, which is effective in fabricating both submicron and nanometric devices. The system employs a high brightness single crystal (100) LaB6cathode and an in‐lens octupole deflector. The JBX‐5D II is fully computer controlled which permits automatic switching of the accelerating voltage between 50 and 25 kV, of writing modes between large and small currents, and of different scanning fields. The ability to switch writing modes permits rapid writing of devices with geometries as small as 10 nm with a fine beam and a coarser beam to be used on larger geometries. The present paper deals with some of the characteristics occurring after switching between writing modes. Experimental results will also be reported on voltage stability and probe currents. The mark detection technology for nanometer writing will be presented along with experimental results for an 80 Å probe size.

ISSN:0734-211X    

DOI:10.1116/1.583352

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

EBS‐5 is a vector scan electron beam lithography system for research and development which evolved from the EBS‐4 system developed by Hughes Research Laboratories in 1977–1980. The EBS‐5 system features higher throughput, improved diagnostics, and more user friendly software. The computer architecture of EBS‐5 consists of a Micro VAX computer and a distributed microprocessor control system, which achieves continuous writing speeds of 13 MHz. A deflection amplifier has been developed which achieves a rise time of 80 ns. The ratio of noise and drift currents to the signal current is lower than 1×10−5in both the deflection amplifier and the lens supplies to ensure the reproducible exposure of submicron patterns. Extensive software was developed to support the layout and fracturing of pattern data.

ISSN:0734-211X    

DOI:10.1116/1.583353

出版商:American Vacuum Society    

年代:1986

数据来源: AIP