Process and apparatus for applying charged particles to a substrate, process for forming a layer on a substrate, products made therefrom

• US 6,544,599 B1
• Filed: 07/31/1996
• Issued: 04/08/2003
• Est. Priority Date: 07/31/1996
• Status: Expired due to Term

• Current Assignee: The Board of Trustees of the University of Arkansas (University of Arkansas System)
• Original Assignee: The Board of Trustees of the University of Arkansas (University of Arkansas System)
• Inventors: Malshe, Ajay P., Naseem, Hameed A., Brown, William D., Beera, Rajan A.
• Primary Examiner(s): PARKER, FREDERICK JOHN
• Application Number:
  US08/688,957
• Time in Patent Office: 2,442 Days
• Field of Search: 427/457, 427/474, 427/475, 427/476, 427/477, 427/479, 427/480, 427/483, 427/62, 427/383.1, 427/397.7, 427/249.12, 427/249.14, 427/249.15, 427/249.17
• US Class Current: 427/475
• CPC Class Codes: C23C 16/02 Pretreatment of the material to be coated C23C16/04 takes precedence
• CPC Class Codes: C23C 16/0254 Physical treatment to alter the texture of the surface, e.g. scratching or polishing
• CPC Class Codes: C23C 16/274 using microwave discharges
• CPC Class Codes: C23C 4/12 characterised by the method of spraying
• CPC Class Codes: C23C 4/123 Spraying molten metal

Abstract

Method and apparatus for seeding silicon substrates with diamond particles by electrostatic seeding. Method further includes either application of heat to form the particles into a layer, or chemical vapor deposition of diamond layer onto the particles. Disclosed products include silicon substrate having electrostatically affixed diamond particles, silicon substrate having particles at a density of at least 10¹² particles per cm², and silicon substrate having polycrystalline layer having nucleation density of at least 10¹² particles per cm².

Claims

1. A method for deposition of particles onto a substrate, the method comprising:

(a) providing dry particles with electrostatic charges to form dry charged particles;

(b) providing the substrate with an electrostatic potential suitable to electrostatically attract the dry charged particles;

(c) contacting the dry charged particles with the substrate to form a particle coated substrate;

(d) growing a polycrystalline layer on the particle coated substrate;

wherein the particles comprise at least one selected from the group consisting of cubic boron nitride, tungsten carbide, silicon carbide, aluminum oxide, silicon nitride, yttrium-based superconductors, thallium-based superconductors, and combinations thereof, and wherein the substrate comprises at least one selected from the group consisting of silica, silicon, alumina, molybdenum, steel, silicon carbide, tungsten carbide, tungsten, silicon nitride, nickel, yttrium-based superconductors, thallium-based superconductors and combinations thereof; and

(e) forming a crystalline layer onto the particles, wherein the crystalline layer comprises at least one selected from the group consisting of cubic boron nitride, tungsten carbide, silicon carbide, aluminum oxide, silicon nitride, and combinations thereof.

2. The method of claim 1, further comprising (f) heating the particle coated substrate to adhere the particles of the particle coated substrate to the substrate.

3. The method of claim 1, wherein the particle coated substrate comprises at least about 10¹⁰ particles per cm².

4. A method for deposition of particles onto a substrate, the method comprising:

(a) dispersing particles into a liquid to create a dispersion;

(b) aerosolizing the dispersion of the particles;

(c) drying the particles to form dry particles capable of becoming electrostatically charged;

(d) electrostatically charging the dry particles of the dispersion with electrostatic charges of one polarity to form dry charged particles;

(e) providing the substrate with electrostatic charge suitable to electrostatically attract the dry charged particles;

(f) contacting the dry charged particles with the substrate to form a particle coated substrate;

(g) growing a polycrystalline layer on the particle coated substrate;

wherein the dry particles comprise at least one selected from the group consisting of cubic boron nitride, tungsten carbide, silicon carbide, aluminum oxide, silicon nitride, yttrium-based superconductors, thallium-based superconductors, and combinations thereof, and wherein the substrate comprises at least one selected from the group consisting of silica, silicon, alumina, molybdenum, steel, silicon carbide, tungsten carbide, tungsten, silicon nitride, nickel, yttrium-based superconductors, thallium-based superconductors and combinations thereof; and

(h) forming a crystalline layer onto the particles, wherein the crystalline layer comprises at least one selected from the group consisting of cubic boron nitride, tungsten carbide, silicon carbide, aluminum oxide, silicon nitride, and combinations thereof.

5. The method of claim 4, further comprising (i) heating the particle coated substrate to adhere the particles of the particle coated substrate to the substrate.