Bell Telephone Laboratories

At&t Bell Laboratories

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

Legrand G Van Uitert

Shobha Singh

George J Zydzik

Irfan Camlibel

Leo F Johnson

Bertram Schwartz

Aland K Chin

John R Zuber

Stuart H Wemple

Howard Joseph Guggenheim

Hans J Stocker

William Henry Grodkiewicz

William A Bonner

Gou-Chung Chi

Mauro Di Domenico, Jr

William H Grodkiewicz

David T Ekholm

Shobha Sing

Semiconductor devices are described which are made by a process involving the use of certain types of glass layers. These glass layers have high silica content, small amounts of boron oxide and optionally small amounts of aluminum oxide. The glass layers are put down by e-beam deposition procedure using a glass target made from restructured glass. Commercial availability of such glass makes the procedure very convenient. Such glass layers are advantageously used as barrier layers in annealing procedures used when semiconductors are doped (e.g., ion implantation in semiconductors) and as encapsulating layers in finished devices.

Devices and device fabrication with borosilicate glass

A fabrication technique is described for making various devices in which a type of glass is used as a surface protection layer. The glass layers are put down by particle bombardment (generally sputtering or e-beam bombardment) of a phosphorus-containing silicate glass target. Devices with such layers are also described. Such glass layers are highly advantageous as encapsulating material, diffusion barrier layers, etc., particularly for optical type devices and certain semiconductor devices. Particularly important is the preparation procedure for the glass target used in the bombardment process. The glass layers are moisture stable, act as excellent barriers against diffusion, and are usable up to quite high temperatures without cracking or peeling. The glass layers also provide long-term protection against atmosphere components including water vapor, oxygen, atmosphere pollution contaminants, etc.

Fabrication of devices using phosphorus glasses

Proposed is a method of fabricating III-V and II-VI compound semiconductors and a resulting product where there is formed on the surface a coating which can function as a diffusion mask and/or a passivation layer. The coating is a silicon layer deposited by a method which does not damage the semiconductor surface.

Coating of III-V and II-VI compound semiconductors

A process is described for doping compound semiconductors using a metal fluoride (e.g., ZnF.sub.2) as the source of dopant. The anhydrous metal fluoride is put down on the surface of the compound semiconductor, capped with a suitable encapsulant and heat treated to promote the diffusion. The heat treatment can be carried out in air without danger of surface damage to the compound semiconductor. Also, the diffusion is better controlled as to depth of diffusion and boundary delineation.

Diffusion procedure for semiconductor compound

A process is described for fabricating various optical devices including photodiodes in which a protective dielectric layer is put down on the surface of the device prior to heating to temperatures over about 250-300 degrees C. Such devices have excellent performance characteristics including low dark current and low noise figures.

Preparation of photodiodes

Optical communications networks may be implemented by means of a patterned layer of an optically transparent material on a substrate. Where an optical path terminates, e.g., at an on-off switch, it is desirable to optically terminate a waveguide so as to minimize spurious signals due to reflection. The invention provides for optical termination of a waveguide by essentially complete absorption of light. Absorption is effected in a portion of the waveguide which comprises light absorbing centers such as, e.g., carbon or metal particles, anions, cations, or molecules which absorb light at desired wavelengths. Absorbing centers may be comprised in a central portion of a waveguide or, more conveniently, in a portion adjacent to a central portion. In the interest of minimizing reflections, interaction between light and absorbing centers increases gradually in a direction of light propagation as may be due to gradually increasing concentration of absorbing centers or to taper in a waveguide cladding portion, core portion, or absorbing portion.

Optical waveguide termination

Magnetic garnet compositions grown from a novel flux comprising a mixture of Li.sub.2 MoO.sub.4 and R.sub.2 (MoO.sub.4).sub.3 wherein R represents yttrium or a rare earth element having an atomic number from 62 to 71 have appropriate magnetic properties for use in bubble domain devices. Items produced are uniform in composition and may be of submicron thickness.

Technique for the growth of magnetic garnet compositions

Electrically activated components such as switches, modulators, attenuators, and mode selectors are disclosed which can be used in networks of waveguides in optical communications systems. Disclosed components comprise an electrochromic medium in combination with a suitable ion source and means for producing a variable electric field across the medium. A change of color in the medium in response to variation of the electric field strength is instrumental in influencing direction and intensity of light propagating in a network.

Electrochromic optical device

Electrically activated optical switches, couplers, and modulators are disclosed which can be incorporated in waveguide networks in optical communications systems. Disclosed devices comprise an electroplating medium in combination with a suitable source of an electric field whose strength can be varied to cause transition of the electroplating medium between plated and unplated states. Changes of reflectivity and refractive index are the bases of switching and coupling applications, respectively.

Electro-optical device based on electroplating action

ZnCl.sub.2 optical fibers are advantageously used for transmission of radiation in the infrared portion of the spectrum. Losses as low as 10.sup.-3 dB/km may be obtained when radiation of wavelength between 3.0 and 4.5 microns is transmitted in such fibers. Fabrication techniques allow for the formation of graded fibers to further improve transmission characteristics.

Zinc chloride optical fibers for transmission in the infrared

Certain structures are described for solid state electrical switches which employ electrochromic material. These structures involve use of a common base contact for both switching and readout circuits. The structures are particularly easy to fabricate using integrated circuit techniques and exhibit reduced electrical shorts due to reduced migration of metallic ions.

Structure for solid state switch

A solid state electrical switch is described which exhibits high off/on resistance ratios and low insertion loss. An additional advantage is that removal of the switching energy does not alter the status (off or on) of the switch. The active solid state material in the switch is an electrochromic material (e.g., tungsten trioxide) which undergoes a transformation from insulator to metallic conductor on injection of certain ions.

Solid state electrical switch employing electrochromic material

Devices of the nature of magnetic bubble devices, but in which 'bits' take the form of light spots, are described. A prototypical device takes the form of an electroluminescent, photoconducting film straddled by orthogonal arrays of insulated strip electrodes forming closely spaced intercept positions so arranged that during operation such intercepts are sequentially biased. A light spot once nucleated--e.g., through a combination of electroinduced and photoinduced luminescence, is stepped by applying bias below nucleation threshold. Devices may serve a variety of memory and/or logic functions.

Electroluminescent optical devices

A process is described for producing devices with gold films on surfaces composed of certain inorganic fluoride compounds. An adhesion compound such as lead fluoride, cadmium fluoride or tin fluoride or mixtures of these compounds is interspersed between inorganic fluoride surface and gold film. This process is particularly attractive for the fabrication of electrochromic display devices and solid-state switches. This procedure insures good adhesion of gold film to inorganic fluoride and insures high reliability in the manufacture of such devices. In addition, electrodes made in accordance with the invention have highly desirable electrical characteristics including ohmic resistance characteristics and low electrode resistances.

Growing community of inventors

Morris Township, NJ, United States of America

Legrand G Van Uitert