摘要:

Image‐projection ion‐beam lithography is an attractive alternative for submicron patterning because it may provide high throughput; it uses demagnification to gain advantages in reticle fabrication, inspection, and lifetime; and it enjoys the precise deposition characteristics of ions which cause essentially no collateral damage. This lithographic option involves extracting low‐mass ions (e.g., He+) from a plasma source, transmitting the ions at low voltage through a stencil reticle, and then accelerating and focusing the ions electrostatically onto a resist‐coated wafer. While the advantages of this technology have been demonstrated experimentally by the work of IMS (Austria), many difficulties still impede extension of the technology to the high‐volume production of microelectronic devices. We report a computational study of a lithography system designed to address problem areas in field size, telecentricity, and chromatic and geometric aberration. We present a novel ion‐column‐design approach and conceptual ion‐source and column designs which address these issues. We find that image‐projection ion‐beam technology should in principle meet high‐volume‐production requirements. The technical success of our present relatively compact‐column design requires that a glow‐discharge‐based ion source (or equivalent cold source) be developed and that moderate further improvement in geometric aberration levels be obtained. Our system requires that image predistortion be employed during reticle fabrication to overcome distortion due to residual image nonlinearity and space‐charge forces. This constitutes a software data preparation step, as do correcting for distortions in electron lithography columns and performing proximity‐effect corrections. Areas needing further fundamental work are identified.

ISSN:1071-1023    

DOI:10.1116/1.584594

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

In the coming years, excimer lasers will play two important roles in microelectronic fabrication: as new light sources for submicron photolithography, and for direct surface patterning by ablation or etching. Using this latter application, results are presented for 248 nm excimer laser formation of micron‐sized patterns in several materials by image projection. Photoablation was used to produce patterning in polyimide and a fluorocarbon polymer, while micropatterning by photoetching is demonstrated in copper and silicon using chlorine vapor. The results are discussed both in terms of the optical characteristics of the projection apparatus, and from the point of material response.

ISSN:1071-1023    

DOI:10.1116/1.584595

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

The applications of a contrast enhancement material, which is composed of 5‐diazo‐meldrum’s acid as a photobleachable reagent, poly(styrene‐co‐maleic acid half‐isopropylate) as a matrix resin, and diethylene glycol dimethyl ether as a solvent, to a photobleachable deep UV resist are presented. The contrast enhancement material with high‐contrast capability was very effective on such a resist, and high‐aspect‐ratio patterns of the resist were successfully obtained. The material characterizations of the contrast enhancement material have been also demonstrated using positive resist optical lithography model (PROLITH).

ISSN:1071-1023    

DOI:10.1116/1.584596

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

A new and simple high‐aspect‐ratio, single‐layer resist process for the manufacture of very large scale integration (VLSI) devices is described. Before the exposure step in the conventional process, an alkaline surface treatment is added to the positive photoresist. This treatment inhibits the dissolution of the unexposed resist layer during development, which leads to a high‐aspect‐ratio resist pattern. Excellent submicron resist patterns are obtained with a large focus latitude using this simple method.

ISSN:1071-1023    

DOI:10.1116/1.584597

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

A new technique has been developed for the growth of epitaxial silicon layers thin enough to be used as active regions of highly scaled transistors. The method, referred to as rapid thermal vapor phase epitaxy, is an extension of standard dichlorosilane vapor phase epitaxy (VPE) to an appropriate time/temperature regime. To do this unique wafer heating and cooling arrangements have been developed and combined with a high‐vacuum/low‐temperature growth environment. The films grown with this technique are selective without the addition of HCl for thicknesses below 1500 Å. X‐ray and electron channeling results indicate that they are single crystal.

ISSN:1071-1023    

DOI:10.1116/1.584554

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

The interaction of oxygen with a Si(100)–As surface has been studied by a homemade combined surface analysis spectrometry with a molecular beam epitaxy system. This paper confirms that an As layer is a good passivation film for the Si surface and describes a study concerning all processes of oxygen adsorption on a Si(100)–As surface for the first time. It is shown that the oxygen coverage at saturation is 0.5 monolayer, i.e., adsorption sites are reduced by one‐half with the existence of an As layer and the initial sticking coefficientSSi–Asoon the Si(100)–As surface was found to be 5.6×10−3, which is ten times less than that for a clean Si(100) surface. The passivating effect of the As on the Si surface is interpreted with the existence of lone‐pair states instead of dangling‐bond states.

ISSN:1071-1023    

DOI:10.1116/1.584555

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

Electronic properties of Si and Mg implants in undoped semi‐insulating GaAs are studied. The activation of the implants is achieved by rapid thermal annealing. The effects of implantation dose and anneal temperature on the measured electrical activity are investigated. In spite of similar depth distributions and implantation damage characteristics, a marked difference between the activations of the Si and the Mg ions is observed for the dose range considered (3×1012–1×1014cm−2). Lattice strain measurements performed by x‐ray rocking curves indicate that the residual implantation damage after annealing is not largely responsible for this difference. The difference is mostly electronic in character, as also suggested by photoluminescence measurements. At high annealing temperatures, changes in the compensating properties of undoped semi‐insulating GaAs are suspected, and are found to play an important role in the activation of implanted ions, affecting then‐ andp‐type dopants conversely.

ISSN:1071-1023    

DOI:10.1116/1.584556

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

The effective density of interface states that exist at the metal–semiconductor Schottky barrier formed between W–Ti and silicon implanted (n‐type) GaAs has been characterized using forward‐biased capacitance–voltage (C–V) measurements. The Schottky diodes were fabricated by sputtering from a tungsten titanium target under different nitrogen gas ambients of 0%, 6%, and 12%. The nitrogen incorporation and interface stability were verified by secondary ion mass spectroscopy (SIMS) and Rutherford backscattering (RBS). The results of this study clearly show that the lowest effective density of interface states was obtained for the highest nitrogen ambient of 12% at a deposition rate of 10 nm/min.

ISSN:1071-1023    

DOI:10.1116/1.584557

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

GaAs layers grown by molecular‐beam epitaxy (MBE) have been postgrowth hydrogenated by implanting low‐energy hydrogen ions with a Kaufman source. Changes in the concentration of deep and shallow levels have been studied by DLTS andC–Vmeasurements, respectively, for different hydrogen doses. A close match is obtained between the present results and those obtained for GaAs grown by the same MBE machine in hydrogen backpressure. Therefore, it is concluded that MBE growth with hydrogen results in hydrogen incorporation in the layers, and hence, in the passivation of shallow and deep levels.

ISSN:1071-1023    

DOI:10.1116/1.584558

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

Room‐temperature photoreflectance (PR) measurements have been used to investigate the optical transition energies in InxGa1−xAs/GaAs strained layer superlattice structures grown by molecular‐beam epitaxy (MBE). Sharp PR features indicating excellent optical quality of these MBE grown structures were observed. The transition energies were calculated and PR spectra fitted to the theoretical line shape expression. By observing the variation of Cl‐Lbl (where Cl is the first conduction subband in InGaAs layers and Lbl is the first light‐hole subband in the GaAs layers) type II superlattice transition, which cannot be observed with photoluminescence even at low temperatures, a conduction‐band discontinuity of 70% was obtained. Further, an important outcome of this study is the observation of strong PR features from the spatially indirect Cl‐Lbl transition which indicates that the modulation of band to band transitions can be a dominant PR line shape determining mechanism.

ISSN:1071-1023    

DOI:10.1116/1.584559

出版商:American Vacuum Society    

年代:1989

数据来源: AIP