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Films of catenated phosphorus materials, their preparation and use, and semiconductor and other devices employing them
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Inventors: Michel, Christian G.; Schachter, Rozalie; Kuck, Mark A.; Baumann, John A.; Raccah, Paul M.;
Assignee: Stauffer Chemical Company (Westport, CT)
Primary Examiner: Gibson; Sharon A.
Assistant Examiner:
Attorney, Agent or Firm: Davis, IV; F. Eugene
High phosphorus polyphosphides, namely MP.sub.x, where M is an alkali metal (Li, Na, K, Rb, and Cs) or metals mimicking the bonding behavior of an alkali metal, and x=7 to 15 or very much greater than 15 (new forms of phosphorus) are useful semiconductors in their crystalline, polycrystalline and amorphous forms (boules and films). MP.sub.15 appears to have the best properties and KP.sub.15 is the easier to synthesize. P may include other pnictides as well as other trivalent atomic species. Resistance lowering may be accomplished by doping with Ni, Fe, Cr, and other metals having occupied d or f outer electronic levels; or by incorporation of As and other pnictides. Top contacts forming junction devices doped with Ni and employing Ni as a back contact comprise Cu, Al, Mg, Ni, Au, Ag, and Ti. Photovoltaic, photoresistive, and photoluminescent devices are also disclosed. All semiconductor applications appear feasible. These semiconductors belong to the class of polymer forming, trivalent atomic species forming homatomic, covalent bonds having a coordination number slightly less than 3. The predominant local order appears to be all parallel pentagonal tubes in all forms, including amorphous, except for the monoclinic and twisted fiber allotropes of phosphorus. Large crystal monoclinic phosphorus (a birefringent material) in two habits, a twisted fiber phosphorus allotrope and a star shaped fibrous high phosphorus material are also disclosed. Single and multiple source vapor transport, condensed phase, melt quench, flash evaporation, chemical vapor deposition, and molecular flow deposition may be employed in synthesizing these materials. Vapor transport may be employed to purify phosphorus. The materials may be employed as protective coatings, optical coatings, fire retardants, fillers and reinforcing fillers for plastics and glasses, antireflection coatings for infrared optics, infrared transmitting windows, and optical rotators. |
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DETAILED DESCRIPTION We claim: 1.
A solid film of MP.
sub.
x deposited on a substrate where M is one or more metals and P is one or more pnictides.
2.
The film defined in claim 1 wherein M is one or more alkali metals.
3.
The film defined in claims 1 or 2 wherein x is 15.
4.
The film defined in claims 1 or 2 wherein M is potassium.
5.
The film defined in claim 1 wherein said film is polycrystalline.
6.
The film defined in claim 1 wherein said film is amorphous.
7.
The film defined in claim 6 wherein said film is free from grain boundaries.
Description:
TECHNICAL FIELD This invention relates to films of catenated phosphorus materials, their preparation and use, and to semiconductor and other devices employing them.
These materials include high phosphorus polyphosphides (i.
e.
, phosphides where the polymeric nature is maintained), alkali metal polyphosphides, monoclinic phosphorus and new forms of phosphorus.
Vapor transport is employed in making the crystalline, polycrystalline and amorphous phosphorus and polyphosphide materials in bulk, thick and thin films.
Flash evaporation and chemical vapor deposition are used to make thin films.
A condensed phase technique is utilized in producing crytalline and polycrystalline polyphosphides.
Diffusion doping is employed to raise the conductivity of these materials.
Rectifying junctions are formed on the materials by appropriate metal contacts.
The film materials may be used as optical coatings.
Powdered crystals and amorphous materials may be used as fire retardant fillers.
The crystalline materials, especially the fiberous forms, may be employed as the high tensile components of reinforced plastics.
BACKGROUND ART During the past several decades, the use of semiconductors has become ever increasingly widespread and important.
Silicon based semiconductors, for example, have generally been successful in providing a variety of useful devices, such as p-n junction rectifiers (diodes), transistors, silicon control rectifiers (SCR's), photovoltaic cells, light sensitive diodes, and the like
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