Showing papers on "Chemical vapor deposition published in 1973"

Chemical Vapor Deposition of Thin‐Film Platinum

Abstract: Chemical vapor deposition of platinum for microelectronic applications has been studied with the aim of avoiding the radiation damage to dielectrics caused by sputter or e‐gun deposition. Two known CVD methods—the pyrolysis of Pt acetylacetonate and the reduction of —were tried and judged unsatisfactory for either purity or adherence. A novel method of Pt deposition using the trifluorophosphine complex is reported. The process is simple and reliable, and produces adherent bright films of crystals on a variety of substrates at 200°–300°C in 1 atm hydrogen. The Pt contains small amounts of residual phosphorus, mostly concentrated at the surface. Resistivity of 750Aa films is 1.8 times that of bulk Pt. MOS capacitors with CVD Pt field plates on both and alone have shown good stability under bias‐temperature aging. CVD Pt and Si interdiffuse readily to form ohmic or Schottky diode contacts.

Growth of boron‐doped diamond seed crystals by vapor deposition

Abstract: p‐type semiconducting diamond was grown by vapor deposition from a 0.83% diborane in methane gas mixture at 1050°C and 0.2 Torr on 0 to 1‐μ nominal size natural type‐I diamond powder. Total mass increases of about 9% were achieved which correspond to average linear growth rates of less than 10−3 μ/day. Evidence showing the growth was boron‐doped diamond included chemical etching, x‐ray and electron diffraction, density measurements, Seebeck and resistivity measurements, chemical analysis, optical measurements, induced electron emission spectroscopy, and scanning electron microscopy. The crystalline quality of the new diamond has not been established; it may be highly defective. A distinct change in color of the diamond seed crystals from an off‐white or gray for virgin crystals to light blue after growth was observed. The results are further confirmation that diamond may be grown at low pressures where it is thermodynamically metastable with respect to graphite. It is also further evidence that boron is t...

Chemical vapor deposition of luminescent films

Abstract: Method for depositing a luminescent film comprising vaporizing into a nonreactive carrier gas at least one betadiketonate of yttrium, lanthanum, gadolinium, and lutetium, and at least one beta-diketonate of a lanthanide that is an activator for the luminescent film; and then contacting the vapor-laden carrier gas with a heated substrate. The beta-diketonates are thermally decomposed to form oxides which deposit on the substrate. The method is continued until the desired film thickness is deposited. There may be one or more reactant gases present for preventing the deposition of carbon and/or for producing a luminescent sulfide. The carrier gas may contain a vanadium-containing beta-diketonate for producing a luminescent vanadate. The luminescent film may be annealed at temperatures above 500 DEG C to enhance the luminescence of the film.

Epitaxial growth of 6H SiC in the temperature range 1320–1390°C

Abstract: High‐quality epitaxial layers of 6H SiC have been grown on 6H SiC substrates with the growth direction perpendicular to the crystal c axis. The growth was by chemical vapor deposition from methyltrichlorosilane (CH3SiCl3) in hydrogen. Epitaxial layers up to 80 μm thick were grown at rates of 0.4 μm/min. Attempts at growth on the (0001) plane of 6H SiC substrates under similar conditions resulted in polycrystalline cubic SiC layers. Optical and x‐ray diffraction techniques were used to characterize the grown layers.

Chemical vapor deposition of luminescent films

Abstract: Method for depositing a luminescent film upon a substrate comprising vaporizing into a nonreactive carrier gas (1) at least one member of a first group consisting of hydrides and alkyls of M 1 , wherein M 1 is at least one of silicon, germanium, boron, phosphorus, and aluminum, (2) at least one volatile M 2 -containing organo-metallic compound of a second group, wherein M 2 is at least one of zinc, cadmium, magnesium, calcium, beryllium, strontium, or barium, and (3) at least one volatile M 3 -containing organo-metallic compound of a third group, wherein M 3 is at least one activator for said luminescent film. The vapor-laden carrier gas and the oxidizing gas are contacted with the substrate which is at temperatures in the range of about 300° to 700°C. The reaction is continued unitl the desired thickness of luminescent film is achieved.

Chemical Vapor Deposition of Electronic Materials

Abstract: Chemical vapor deposition (CVD), as the name implies, involves the formation of a deposit on a substrate caused by the reaction of chemicals transported to the substrate in the vapor phase. It is a very old technique which dates at least as far back as the chemical transport studies of Bunsen (1) and Sainte-Claire Deville (2) in the mid-nineteenth century, and which achieved commercial significance as long ago as 1880 when it was used for coating filaments in the incandescent lamp industry (3). Over the course of approximately 100 years it has developed into a very important method for material synthesis and today has application to a broad spectrum of compounds ranging from relatively easily prepared amorphous and polycrystalline deposits used as protective coatings to highly sophisticated epitaxial single crystalline films used in semiconductor devices. The growing importance of CVD is derived from the inherent versatility of this synthesis method which permits the preparation of virtually any material in essentially any geometry. In addition, CVD has a number of unique advantages, in comparison with most synthesis techniques, which include the ability to synthesize materials at relatively low temperatures and to directly synthesize compounds represented by any region of a phase diagram. This latter ability is very important for the preparation of compounds having incongruent melting points and for the synthesis of solid solutions or alloys. The ability to prepare materials at low temperatures is beneficial for achieving high purity since contamination resulting from diffusion processes and unwanted reactions can be minimized. Also, homogeneity and stoichiometry can be more easily controlled in compounds which have high equilibrium dissociation pressures near their melting temperatures, and the integrity of substrate materials can be more easily assured. An additional advantage of CVD is that it readily accommodates the

The epitaxial growth of ZnO on sapphire and MgAl spinel using the vapor phase reaction of Zn and H2O

Abstract: The gas phase reaction of Zn and H2O in a He carrier gas has been used as the basis for the chemical vapor deposition of ZnO on sapphire and MgAl spinel. Deposit characteristics were studied as a function of reactor linear gas stream velocity, Zn/H2O vapor phase ratio, temperature and substrate preparation. It was round that the substrate support can influence the surface morphology significantly and that in situ pretreatment can affect epitaxial relationships between deposit and substrate. Transparent, visually smooth deposits of (11–24) ZnO can be obtained on chemically polished (0001) sapphire at 815°C using average linear gas stream velocities, ν, of 6-12 cm/sec referenced to room temperature in conjunction with a Zn/H2O reactor input-pressure ratio of 0.02–0.09 (using Zn reactor pressures of 1.2–5.0 × 10−3 atm) . The substrates are given an H2O in situ pretreatment at 900°C prior to deposition at ν = 3 cm/sec with the partial pressure of H2O in He = 5.7 × 10 atm.

Ohmic contacts to silicon

Abstract: Ohmic contact to relatively high resistivity n-type silicon is made by forming a thin layer of platinum on the silicon surface by means of chemical vapor deposition (CVD) using a phosphorus compound of platinum. The structure then is sintered by heating at about 700* C. for from five to ten minutes thereupon forming a good ohmic contact of the platinum silicide type without the necessity of the separate impurity diffusion treatment usually required to increase the surface impurity concentration.

Method for making III{14 V compound semiconductor devices

Abstract: On a surface of a III-V compound semiconductor substrate an Si3N4 layer is first deposited by a chemical vapor deposition method at a temperature between 600 DEG and 800 DEG C with a relatively low flow rate of SiH4 and NH3, so as to have a growth rate of the Si3N4 layer less than about 100 A/min. Then a phosphosilicate glass layer is deposited on the Si3N4 layer also by a chemical vapor deposition method. A double layer of Si3N4 and phosphosilicate glass thus formed serves as protective layer and/or mask for the selective diffusion, whereby such double layer avoids a warping of the substrate.

Bonding of sapphire to sapphire by eutectic mixture of aluminum oxide and zirconium oxide

Abstract: Bonding of an element comprising sapphire, ruby or blue sapphire to another element of such material with a eutectic mixture of aluminum oxide and zirconium oxide. The bonding mixture may be applied in the form of a distilled water slurry or by electron beam vapor deposition. In one embodiment the eutectic is formed in situ by applying a layer of zirconium oxide and then heating the assembly to a temperature above the eutectic temperature and below the melting point of the material from which the elements are formed. The formation of a sapphire rubidium maser cell utilizing eutectic bonding is shown.

Chemical Vapor Deposition of Epitaxial Films of Yttrium Iron Garnet and Gallium-Substituted Yttrium Iron Garnet and a Thermodynamic Analysis

Abstract: Epitaxial single-crystal films of yttrium iron garnet (YIG) and Ga: YIG (Y3Fe5-xGaxO12) were grown by chemical vapor deposition. The garnet is deposited by the reaction of gaseous metal chlorides with O2 at 1150°C and 5 torr. The chlorides are generated in-line by reacting Cl2 gas with a Y-Fe(-Ga) alloy. A computer-aided thermodynamic calculation was developed to determine which of several possible solids in a multicomponent CVD system will be deposited for a given set of growth conditions. The calculation determines an intermediate equilibrium among all gaseous species and then identifies the solid phase most favored to be deposited from the supersaturated gas phase. The results of the calculations agreed well with experiment and have been useful in finding the conditions for optimum growth of garnet. This type of calculation can be applied to other multicomponent CVD systems.

Gas analysis during the chemical vapor deposition of carbon

Abstract: From fourth international conference on chemical deposition vapor; Boston, Massachusetts, USA (7 Oct 1973). Gas chromatography was used to study gas-phase pyrolysis reactions in carbon CVD studies. Results support a carbon CVD model presented previously. (9 figures, 12 references) (DLC)

Magnetic Properties of Amorphous Metallic Alloys

Abstract: A growing number of amorphous metallic alloys have been obtained by rapid-quenching from the liquid state or by other techniques such as vapor deposition or electrolytic deposition. The purpose of this talk is to review some of the experimental work on the amorphous metallic alloys prepared by the technique of liquid quenching.1 The emphasis will be on the magnetic properties of these metastable alloys.

Method of chemical vapor deposition to provide silicon dioxide films with reduced surface state charge on semiconductor substrates

Abstract: The present invention relates to an improvement in the conventional method of forming silicon dioxide films by a chemical-vapor deposition reaction of a mixture of an oxidizing agent and SiHnCl(4-n), where n is an integer of from 0 to 4. Such conventional methods which are conducted at temperatures of at least 700 DEG C provide silicon dioxide films on silicon substrates which are substantially free of mobile ion contamination as evidenced by insignificant flat-band voltage shift when subjected to standard bias-temperature test conditions; such insignificant flat-band voltage shifts are indicative of a maximum increase of 1 x 1011 charges/cm2 in the flat-band surface charge resulting from such bias-temperature conditions.

Chemical vapor deposition of ZrC in small bore carbon-composite tubes

Abstract: Process conditions are described for the chemical vapor deposition of ZrC from ZrCl/sub 4/--CH/sub 4/--HCl--H/sub 2/--Ar vapor over the temperature range 1320 to 1775 deg K. From an analysis of the process conditions (initial composition of coating gas, axial temperature profile along the tubes, total pressure, and length of deposition time), the subsequent ZrC coat thickness profiles and thermodynamic data, an equation expressing the variation of the axial rate of ZrC deposition is derived. This expression can be used for the estimation of process conditions required to yield a specified ZrC coat profile. Variations of the chlorine and oxygen contents, lattice pararmeter, microstructure of the ZrC deposit and thermal expansion coefficient as a function of deposition temperature are described. (11 figures, 3 tables) (auth)

Circular etch pits in ion‐implanted amorphous silicon films

Abstract: Using a dilute HF solution as the etchant, we found very different etching behaviors between amorphous silicon films prepared by vapor deposition and by ion implantation. The latter are etched preferentially forming circular pits on the surface, but not the former. However, when the evaporated films were subjected to high dosages of ion bombardment and followed by etching, the same kind of circular pits were observed. We conclude that the bombardment of ions can cause weak spots on the amorphous Si surface which possess low resistance to the etching.