# US 5,350,607 A · Ionized cluster beam deposition of sapphire > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,350,607 A - Document ID: US5350607A - Status: Granted - Kind: A - Application number: 07/955,607 - Filed: 1992-10-02 - Granted: 1994-09-27 - Earliest claimed: 1992-10-02 - Assignees: United Technologies Corporation - Inventors: Scott M. Tyson; Richard Y. Kwor; Leonard L. Levenson - Web page: https://patentgrep.com/patent/US5350607A ## CPC - C23C 14/221: {Ion beam deposition (C23C14/46, C23C14/48 take precedence)} - C23C 14/08: Oxides (C23C14/10 takes precedence) - C30B 23/02: Epitaxial-layer growth - C30B 29/20: Aluminium oxides - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR ## Abstract Sapphire, a highly stable oxide of aluminum having the chemical formula of Al.sub.2 O.sub.3, is placed in a crucible. The crucible is heated to vaporize the sapphire therein. The sapphire vapor is ejected through a nozzle in the crucible and into a region having a vacuum pressure of approximately 10.sup.-5 Torr or less. As the vapor leaves the crucible through the nozzle, atom aggregates or clusters are formed through a supercooled phenomenon due to adiabatic expansion. The vacuum region has disposed therein a substrate comprised of one of various materials, including metals, oxides or silicon. The sapphire vapor is accelerated towards the substrate where it deposits on a surface of the substrate in a uniformly distributed thin layer. ## Claims ### Claim 1 A method of depositing a layer of sapphire on a surface of a substrate, comprising the steps of: depositing sapphire in a crucible having a nozzle; positioning said crucible in a vacuum chamber having a first pressure level; positioning said substrate in said vacuum chamber; heating said crucible to a first temperature to cause said sapphire to be vaporized at a second pressure level within said crucible, said second pressure level being greater in magnitude than said first pressure level, such that said vapor is ejected through said nozzle, thereby forming clusters of sapphire by adiabatic expansion, said sapphire clusters being formed in said vacuum chamber outside of said crucible in the vicinity of said nozzle; bombarding said sapphire clusters with electrons, thereby resulting in some number of said sapphire clusters being partially ionized along with some number of sapphire clusters remaining non-ionized; and accelerating both said ionized and non-ionized sapphire clusters toward a surface of said substrate to form a deposited sapphire film thereon of a thickness. ### Claim 2 (depends on 1) The method of claim 1, wherein said first pressure level of said vacuum chamber is no greater than 1.times.10.sup.-5 Torr. ### Claim 3 (depends on 1) The method of claim 1, wherein said crucible is comprised of graphite. ### Claim 4 (depends on 1) The method of claim 1, wherein said step of heating said crucible comprises the step of emitting electrons towards said crucible so as to heat said crucible by electron impact. ### Claim 5 (depends on 1) The method of claim 1, wherein said step of heating said crucible comprises the step of resistive heating. ### Claim 6 (depends on 1) The method of claim 1, wherein said step of accelerating said sapphire clusters towards said substrate comprises the step of applying an acceleration voltage between said crucible and said substrate. ### Claim 7 (depends on 6) The method of claim 6, wherein said acceleration voltage is substantially in the range of 200 to 500 volts. ### Claim 8 (depends on 1) The method of claim 1, further comprising the step of heating said substrate to a second temperature. ### Claim 9 (depends on 8) The method of claim 8, wherein said second temperature is substantially in the range of 400 to 600 degrees centigrade. ### Claim 10 (depends on 1) The method of claim 1, further comprising the step of providing an oxygen partial pressure within said vacuum chamber in the range of 5.times.10.sup.-5 to 1.times.10.sup.-4 Torr. ### Claim 11 (depends on 1) The method of claim 1, wherein said step of bombarding said sapphire clusters with electrons comprises the step of applying an electron ionization current to an electron emitting filament. ### Claim 12 (depends on 11) The method of claim 11, wherein said electron ionization current is in the range of 200 to 300 milliamps. ### Claim 13 (depends on 1) The method of claim 1, wherein said substrate comprises aluminum. ### Claim 14 (depends on 1) The method of claim 1, wherein said substrate comprises an aluminum alloy. ### Claim 15 (depends on 1) The method of claim 1, wherein said substrate comprises an oxide. ### Claim 16 (depends on 1) The method of claim 1, wherein said substrate comprises silicon dioxide. ### Claim 17 (depends on 1) The method of claim 1, wherein said substrate comprises silicon nitride. ### Claim 18 (depends on 1) The method of claim 1, wherein said substrate comprises doped glass. ### Claim 19 (depends on 1) The method of claim 1, wherein said substrate comprises undoped glass. ### Claim 20 (depends on 1) The method of claim 1, wherein said substrate comprises silicon. ### Claim 21 (depends on 1) The method of claim 1, wherein said first temperature of said crucible is controlled by a vibration frequency of a crystal coupled to said substrate, said vibration frequency corresponding to a deposition rate of said deposited sapphire film on said substrate. ### Claim 22 A method for forming a sapphire layer superjacent a substrate, said method comprising the steps of: providing sapphire in a crucible having a nozzle; positioning said crucible and a substrate within a vacuum chamber, said vacuum chamber having a first pressure level, said substrate comprising at least one of single crystal silicon, polycrystalline silicon, amorphous silicon, aluminum, silicon dioxide, silicon nitride, doped glass, undoped glass, and an oxide; heating said crucible to a first temperature to vaporize said sapphire at a second pressure level within said crucible; regulating said heating of said crucible at said first temperature by a vibration frequency of a crystal coupled to said substrate, said vibration frequency corresponding to a deposition rate of said deposited sapphire film on said substrate, such that said second pressure level substantially exceeds said first pressure level, thereby forming clusters of sapphire and ejecting said sapphire clusters from said crucible in the direction of said substrate; ionizing a portion of said sapphire clusters by electron bombardment, thereby providing a remaining portion of non-ionized sapphire clusters; and accelerating both said ionized and said non-ionized clusters toward said substrate, thereby forming a sapphire film superjacent said substrate. ### Claim 23 (depends on 22) The method of claim 22, wherein said regulating comprises the step of: supercooling said ejected sapphire clusters by means of adiabatic expansion. ### Claim 24 (depends on 22) The method of claim 22, wherein said regulating comprises the step of: heating said substrate to a temperature substantially in the range of 400 to 600 centigrade after said sapphire clusters are ejected. ### Claim 25 (depends on 22) The method of claim 22, further comprising the step of: introducing an oxygen partial pressure within said vacuum chamber in the range of 5.times.10.sup.-5 and 10.sup.-4 Torr.