Hughes Aircraft Company

Hughes Aircraft

John W Peters

Jacques F Linder

Robert Y Scapple

Edward M Yee

Ronald T Smith

Mao-Jin J Chern

James T Hall

Thomas C Hall

Frank L Gebhart

The specification discloses a low-temperature process for depositing a layer of a conductive oxide of a chosen metal, such as tin oxide, on the surface of a substrate while simultaneously avoiding damage to the substrate. The process comprises exposing the substrate to a selected vapor phase reactant containing the chosen metal, such as tetramethyl tin, in the presence of neutral, charge-free oxygen atoms formed in a manner which avoids the generation of charged particles and high energy radiation that would damage the substrate. The oxygen atoms react with the vapor phase reactant to form the conductive oxide, which deposits as a layer on the surface of the substrate. In a preferred process embodiment, the neutral oxygen atoms are photochemically generated. This process is especially useful for depositing a layer of a transparent conductive oxide on the surface of a radiation-hardened device while maintaining the radiation-hardness of the device.

Process for depositing a conductive oxide layer

An improved process for depositing an oxide layer on a substrate by exposing the substrate to a selected vapor phase reactant and an oxygen-containing precursor comprising nitrous oxide mixed with molecular oxygen in a predetermined ratio, in the presence of radiation of a selected wavelength. The radiation causes the direct dissociation of the oxygen-containing precursor to form neutral oxygen atoms that react with the vapor phase reactant and form the oxide, which deposits as a layer on the substrate. The rate of reaction to form and deposit the oxide layer is enhanced by the mixing of molecular oxygen with nitrous oxide in the precursor.

Photochemical vapor deposition process for depositing oxide layers

The specification discloses a low temperature process for depositing an epitaxial layer of a selected oxide or a selected sulfide material on a chosen substrate. The substrate is exposed to a chosen vapor phase reactant in the presence of neutral, charge-free oxygen atoms or sulfur atoms to produce a reaction between the atomic species and the vapor phase reactant to form the desired oxide or sulfide and induce the crystalline growth thereof as an epitaxial layer on the surface of the substrate. The atomic oxygen or the atomic sulfur is formed at a low temperature by the photochemical dissociation of a selected oxygen-containing precursor or a selected sulfur-containing precursor, respectively.

Low temperature process for depositing epitaxial layers

An apparatus for photochemical vapor deposition includes an outer reactor shell and a concentric inner shell which define a photochemical reaction zone. A radiation source is centrally located within the transparent inner shell, which isolates the radiation source from the vapor phase reactants present in the reaction zone. A rotating gas manifold is located within the reaction zone to uniformly distribute the vapor phase reactants within the reaction zone. Protective liquid is continually applied to the outer surface of the inner shell and spread into a thin film by wiper blades, to prevent deposition of reaction products onto the outer wall of the inner shell. The central location of the radiation source, along with the protective liquid film, make optimum usage of the reaction-inducing radiation generated by the radiation source. In addition, the rotating gas manifold promotes uniform deposition of layers of selected materials on substrates placed within the reaction zone.

Barrel reactor and method for photochemical vapor deposition

Method for photochemical vapor deposition

A process for depositing on the surface of a substrate a layer of a chosen material having continuous gradations in refractive index in a predetermined periodic pattern. The substrate is exposed to two vapor phase reactants which react upon radiation-inducement to produce the chosen material, and the relative proportion of the reactants is varied in a predetermined and continuous sequence to produce continuous gradations in the stoichiometric composition and refractive index of the deposited layer as a function of thickness. Additionally, predetermined changes in refractive index and/or thickness across the horizontal surface of the substrate may be produced in combination with the change in refractive index as a function of thickness. Diffraction optical elements formed by such a process include various optical filters and reflective optical coatings.

Process for forming a graded index optical material and structures

An improved silicon oxynitride material which is homogeneously chemically bonded and contains minimal free amorphous silicon has improved electrical insulating properties, hardness, scratch resistance, and adhesion. This material is formed on the surface of a selected substrates by a photochemical vapor deposition reaction. First a vapor mixture is formed comprising: ammonia and silane reactants in the ratio of 80:1 or higher; mercury vapors as a sensitizer for the desired photochemical reaction; and a predetermined amount of oxygen. This vapor mixture is introduced into a photochemical vapor deposition chamber containing the selected substrate, and radiation of a predetermined wavelength is simultaneously introduced into the deposition chamber. The selected radiation induces a photochemical reaction between the silane, ammonia, and oxygen to form silicon oxynitride which deposits on the substrate surface. The oxygen reacts with any excess silane to chemically bond and homogeneously incorporate the silicon from the excess silane into the silicon oxynitride material. Thus, the formation of free amorphous silicon from the silane and the heterogeneous incorporation thereof into the silicon oxynitride material are prevented.

Silicon oxynitride material and photochemical process for forming same

The specification discloses a low-temperature process for depositing a layer of a sulfide of a chosen element, such as zinc sulfide, on the surface of a substrate while simultaneously avoiding damage to the substrate. The process comprises exposing the substrate to a selected vapor phase reactant containing the chosen metal, such as dimethyl zinc, in the presence of neutral, charge-free sulfur atoms formed in a manner which avoids the generation of charged particles and high energy radiation that would damage the substrate. The sulfur atoms react with the vapor phase reactant to form the sulfide thereof, such as zinc sulfide, which deposits as a layer on the surface of the substrate. In a preferred process embodiment, the neutral sulfur atoms are generated by photochemical dissociation. In addition, there is disclosed a process for forming a native sulfide layer on the surface of a chosen substrate by exposing the substrate to neutral, charge-free sulfur atoms.

Process for forming sulfide layers

The specification discloses a low-temperature, charge-free process for forming a layer of a native oxide on the surface of a substrate of a chosen semiconductor material. The substrate is exposed to neutral, charge-free oxygen atoms that are the primary oxidizing species and are formed in a manner which eliminates the generation of charged particles or high energy radiation. These oxygen atoms then react with the surface of the substrate to form the native oxide thereof. The use of neutral oxygen atoms avoids damage to the substrate due to exposure to charged particles or high energy radiation, both in the manner in which the oxidizing species is formed and in the manner in which the native oxide layer is grown. In a preferred embodiment, the neutral oxygen atoms are formed by exposing a chosen oxygen-containing precursor to radiation of a selected wavelength to cause the direct dissociation of the precursor to generate oxygen solely in atomic form.

Low-temperature charge-free process for forming native oxide layers

Process for forming sulfide layers by photochemical vapor deposition

The specification discloses a low temperature process for forming an effective insulating layer of a selected oxide on the surface of a chosen conductive substrate. The oxide so formed has low pinhole density, good surface morphology, and good step coverage. In addition, the disclosed process simultaneously minimizes the deformation or restructuring of the surface of a temperature-sensitive conductive substrate, which would produce unwanted hillocks or spikes that degrade the insulating properties of the oxide. In accordance with the disclosed process, the substrate is exposed to a chosen vapor phase reactant in the presence of neutral, charge-free atomic oxygen to produce a reaction between the atomic oxygen and the vapor phase reactant to form the selected oxide, which deposits on the surface of the conductive substrate. Improved multilayer structures comprising multiple layers of conductive material separated by an oxide dielectric layer are formed by the disclosed process.

Low temperature process for depositing an oxide dielectric layer on a

The specification discloses a low temperature process for depositing oxide layers on a substrate by photochemical vapor deposition, by exposing the substrate to a selected vapor phase reactant in the presence of photochemically generated neutral (un-ionized) oxygen atoms. The oxygen atoms react with the vapor phase reactant to form the desired oxide, which deposits as a layer on the substrate. The use of photochemically generated neutral oxygen atoms avoids damage to the substrate due to charge bombardment or radiation bombardment of the substrate. The deposited oxide layer may optionally incorporate a selected dopant material in order to modify the physical, electrical, or optical characteristics of the oxide layer.

Low temperature process for depositing oxide layers by photochemical

The specification discloses a mobile transparent window apparatus and method for use in a photochemical vapor deposition system having a reaction chamber with a quartz window integral with the top surface thereof, which prevents undesirable deposits on the quartz window and thereby enhances the efficiency and rate of the deposition process. The apparatus comprises: (a) a film of a predetermined material that is drawn across the internal face of the quartz window within the reaction chamber, the predetermined material being characterized by being transparent to a selected wavelength of radiation, being stable at the elevated temperature required for the photochemical vapor deposition, and possessing sufficient mechanical strength to be moved across the quartz window; and (b) means for moving the film across the internal face of the quartz window.

Mobile transparent window apparatus and method for photochemical vapor

Low temperature photonitride (LTPN) films of excellent quality have been prepared at temperatures ranging from 300.degree. C. downward to 100.degree. C. by a photochemical vapor deposition process, wherein a mixture of silane, ammonia, and hydrazine is caused to react to form Si.sub.3 N.sub.4 films at the substrate interface. These films are suitable for the preparation of silicon nitride passivation layers on solid-state devices, such as metal-oxide semiconductors (MOS) and charge coupled devices to impart enhanced reliability.

Growing community of inventors

Malibu, CA, United States of America

John W Peters