At&t Bell Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

John M Gibson

Steven D Berger

Raymond T Tung

John Milo Poate

Anthony F Levi

Dale C Jacobson

John C Hensel

Fabrication of devices of micron and submicron minimum feature size is accomplished by lithographic processing involving a back focal plane filter. A particularly important fabrication approach depends upon mask patterns which produce images based on discrimination as between scattered and unscattered radiation by accelerated electrons. Use of such masks is of value as applied to scanning systems providing for dynamic correction of aberrations by physical movement of or field shaping of the objective lens to maintain the optical axis coincident with the scanning information-scanning beam.

Device manufacture involving lithographic processing

Fabrication of devices of micron and submicron minimum feature size is accomplished by lithographic processing involving a back focal plane filter. A particularly important fabrication approach depends upon mask patterns which produce images based on discrimination as between scattered and unscattered radiation by accelerated electrons.

Surfer doll

Fabrication of devices of micron and submicron minimum feature size is accomplished by lithographic processing involving a back focal plane filter. A particularly important fabrication approach depends upon mask patterns which produce images based on descrimination as between scattered and unscattered radiation.

A method for producing, without etching, a perforated layer of epitaxial metal silicide, especially CoSi.sub.2, on a single crystal Si substrate, with epitaxial Si overlying the silicide layer. The layer thickness, and the number and size of the openings in the layer are such as to make the structure suitable as an electronic device, in particular, as a permeable base transistor. The number and/or size of the openings is a function of processing parameters such as the substrate orientation, the annealing temperature of the film, or the Co/Si ratio of the deposited material. A device comprising a perforated silicide layer is also disclosed.

Semiconductor device comprising a perforated metal silicide layer

A method for forming heterostructures comprising multiconstituent epitaxial material, on a substrate comprises formation of a layer of 'precursor' material on the substrate, and momentarily melting the precursor material by pulsed irradiation. The precursor material has the same major chemical constituents as the multiconstituent material to be formed, albeit not necessarily in the same proportions. In at least some systems (e.g., nickel or cobalt silicides on Si), solid state annealing of the re-solidified material often improves substantially the quality of the epitaxial material formed, resulting in substantially defect-free, substantially monocrystalline, material. An exemplary application of the inventive method is the formation of single crystal epitaxial NiSi.sub.2 on Si(100).

Formation of heterostructures by pulsed melting of precursor material

The method for growing heteroepitaxial multiconstituent material on a substrate comprises deposition of a thin disordered layer of a 'template-forming' material, i.e., material containing at least one constituent of the multiconstituent material to be grown, and differing in chemical composition from at least the substrate material, on the substrate surface at a relatively low deposition temperature, raising the substrate temperature to an intermediate transformation temperature, thereby causing the template-forming material to undergo a reaction that results in formation of 'template' material, typically material having substantially the same composition as the multiconstituent material to be grown. Onto the thus formed template layer is then deposited the material for the epitaxial multiconstituent layer. This general process is exemplified by the growth of NiSi.sub.2 on a Si substrate, by first depositing at room temperature about 18.ANG. of Ni (the template-forming material), onto an atomically clean and undamaged Si(111) surface, heating the substrate to about 500.degree. C. for about 4 minutes (thereby reacting the Ni with Si from the substrate to form template material), followed by deposition, onto the now template-covered substrate, of about 250.ANG. of Ni at a rate of about 2.ANG./sec, with the (template-covered) substrate maintained at about 775.degree. C. The inventive method has wide applicability, and permits, inter alia, growth of essentially perfect epitaxial CoSi.sub.2 or NiSi.sub.2 on Si(100). Material grown by the method can be in form of an essentially continuous layer or a patterned layer, and can serve as the substrate for the growth thereon of further epitaxial material of different chemical composition.

Growing community of inventors

Upper Montclair, NJ, United States of America

John M Gibson