Showing papers on "Etching (microfabrication) published in 1971"

Characterization of Silicon Nitride Films

Abstract: Various "silicon nitride" films have been prepared from , N2, , and in an rf‐promoted glow discharge reaction. These films are described primarily through the use of infrared absorption. Aided by ultraviolet absorption, the inclusion of excess silicon or of oxygen in the films is readily followed. Changes in index of refraction, etch rates in HF acid, and electrical conductivity of the films are correlated with the optical absorption study. Comparisons of these films with those formed by pyrolysis or by reactive sputtering are made. Some reproducible physical properties of an amorphous film are stated.

Preferential Etching and Etched Profile of GaAs

Abstract: The system has been found to give good results for preferential etching of . The etch rates for the low‐index planes of in this system have been investigated as a function of Br2 concentrations in .The order of the etch rate at 1% Br2 by weight has been found to be planes have been only slightl yetched. The A{111} planes have played an important role for the etched profiles produced by this etching system. A V‐shaped groove, a reverse mesa‐shaped structure, and a triangular prism‐shaped "bridge" have been formed by channels being etched on the {100} planes. The sizes of the V‐shaped groove and the "bridge" have been controlled by the width of the opening in the oxide mask. A channel etched groove in the B{111} planes has also exhibited crystal habit. Interesting etched profiles which are applicable for the design and fabrication of device structures are described.

Josephson Tunneling Barriers by rf Sputter Etching in an Oxygen Plasma

Abstract: A new technique for fabricating Josephson tunneling barriers has been developed. Oxide tunnel barriers with estimated thicknesses from 20 to 50 A have been formed on lead films with indium underlayers and on niobium films. The technique includes an rf sputter etching step in argon for cleaning followed by an rf sputter etching step in oxygen. During the latter, an oxide film is grown having a steady‐state thickness which is attributed to a balance between sputtering and oxidation rates. Different oxide thickness may be obtained by varying process parameters such as oxygen pressure and rf power.

Selective Etching of Gallium Arsenide Crystals in H 2 SO 4 ‐ H 2 O 2 ‐ H 2 O System

Abstract: Selective etching of in the system was studied as a pretreatment to selective deposition. Flat‐bottomed holes were obtained in low solutions, whereas nonplanar holes were obtained in high solutions. Differences between both cases are considered from the etching behaviors under nonselective conditions. Using low solutions, selective etching was conducted on substrates with different crystallographic orientations. Asymmetrical holes were observed in all cases except for holes on the {001} substrate with rectangular windows held parallel to the 〈001〉 direction. The possibility of the revealed planes being the wall in the hole is discussed.

A High‐Yield Photolithographic Technique for Surface Wave Devices

Abstract: In the fabrication of surface wave devices, standard photoresist‐chemical etching techniques often provide a very low yield even at moderate resolutions, frequently cause a degradation of the substrate finish, and in many cases are incompatible with substrates of interest. A photolithographic technique is described in which metalizing is done after a photoresist image is produced on the substrate, thereby circumventing most of the problems inherent in chemical etching. It is shown by means of electron micrographs of photoresist profiles that intimate mask‐substrate contact is essential. Devices with line widths of 1 µm can be produced with high yield.

Conversion of silicon nitride into silicon dioxide through the influence of oxygen

Abstract: When thin films of silicon nitride are annealed in the presence of oxygen, thin films of silicon dioxide are formed on the nitride layers while silicon nitride is consumed. The thickness of the oxide layers which are built up by reaction with dry oxygen, wet oxygen and by a mixture of oxygen and nitrogen in the presence of phosphorus pentoxide, are given as a function of time and temperature. The results are compared with the thermal oxidation of silicon.

Method of making semiconductor devices with selective doping and selective oxidation

Abstract: A method of manufacturing a semiconductor device having an inset oxide pattern obtained by local oxidation, which pattern is bounded only partly by a doped surface zone. According to the invention a first mask is provided on the semiconductor surface after which etching is carried out so that a freely projecting edge of said mask is formed by underetching. During the local doping of the etched surface the masking provided by said edge is used directly or indirectly after which the oxide pattern is provided.

Methods for making transistor structures

Abstract: A high frequency field effect transistor is made by first epitaxially growing semiconductor channel and drain layers over a source layer. An oxide layer is formed on the upper drain layer which acts as a mask during etching of the epitaxial layers. Anisotropic etching of the semiconductor forms a mesa configuration of the channel and drain layers which is overlapped by the upper oxide layer. Metal is then evaporated onto the mesa from a point opposite the oxide layer. The overhanging oxide layer masks part of the mesa, particularly the drain layer, to define precisely the area covered by the evaporated gate contact, as required for high frequency operation. Other embodiments are also described.

Electrochemically Thinned N/N+ Epitaxial Silicon—Method and Applications

Abstract: The method of thinning n/n+ epitaxial silicon wafers by selective anodic dissolution of the substrate in aqueous is described. Some of the properties of the system are discussed and applications are presented. It appears the technique is best suited for use where the material has not had extensive prior processing, especially n+ diffusions, and/or where the epitaxial layer is of high resistivity. The most promising areas of application appear to be: (a) fabrication of thin films for experimental purposes, (b) thinning of simple diode arrays, and (c) solid dielectric isolated IC fabrication. Considerable impediments to use of the process are the necessity of having epitaxial layers of unusual perfection and the fact that local anodic etching occurs at sites of high carrier generation.

Method of making a heat pipe

Abstract: A heat-transfer device or heat pipe having an integral screenwick structure which provides relatively great contact area between the internal working fluid and the heat input. The screen wick is fabricated by a plurality of photographic etching and plating steps.

Silicon nitride-silicon oxide etchant

Abstract: This invention discloses a chemical to etchant and a process for chemically etching silicon nitride-silicon oxide composite structure which may be used, for example in microelectronic devices. The etching process or system utilizes a mixture of phosphoric acid and a fluoborate anion containing compound such as fluoboric acid. The etch rate of the silicon nitride relative to the etch rate of the silicon oxide can be controlled to the desired etch rate by varying the temperature of the etchant and/or adjusting the ratio mixture of the phosphoric acid and the fluoboric acid.

Epitaxial Growth of α-SiC from the Vapor Phase

Abstract: Epitaxial layers of α-SiC are grown on the (0001) and the (000) faces of α-SiC substrates front the silane-propane-hydrogen system. The structure, morphology and growth rate of the layers are studied as a function of the partial pressures of the reactants and the substrate temperature. It appears that the growth process is controlled by the combined effects of propane diffusion and the rate of thermal etching of SiC. The best layers in terms of surface smoothness and crystalline perfection are obtained under low reactant partial pressures (slow growth rate conditions) at temperatures in the vicinity of 1550°C. The epitaxial layers are structurally characterized with X-ray diffraction techniques, electron scanning microscopy, and chemical etching. As grown layers exhibited n-type conduction. p-type boron doped layers are grown by using borane gas in the reactant system. Light emitting p-n junctions are prepared and electrically characterized.

Compound semiconductor device having undercut oriented groove

Abstract: A compound semiconductor device is provided with at least one inwardly splayed groove by a method of etching which takes into account the crystal orientation of the semiconductor material.

Sputter-etching technique for recording holograms or other fine-detail relief patterns in hard durable materials

Abstract: SPUTTER ETCHING HAS BEEN FOUND TO BE CAPABLE OF TRANSFERRING HOLOGRAMS RECORDED ON A PHOTOSENSITIVE SURFACE LAYER COVERING AN UNDERLYING SUBSTRATE MATERIAL FROM THE LAYER TO THE SUBSTRATE MATERIAL ITSELF. THE TRANSFERRED HOLOGRAM IS IN THE FORM OF A RELIEF PATTERN. THIS TECHNIQUE PROVIDES BOTH HIGH FIDELITY AND HIGH RESOLUTION CAPABILITIES IN BOTH THE DEPTH DIMENSION AND IN THE SURFACE DIMENSIONS OF THE TRANSFERRED RELIEF-PATTERN HOLOGRAM, WHICH ARE IN THE ORDER OF ONE MICRON OR LESS, AND IS APPLICABLE TO OTHER FINE-DETAIL RELIEF PATTERNS.

Method of etching copper and alloys thereof

Abstract: A method of etching copper, or its alloys, with an acidic aqueous etching solution containing peroxysulfate and containing an additive which is an azole of the following structures: WHEREIN X, X'' and X'''' which may be the same or different represent any one of hydrogen, amino group, aminoalkyl group having one to three carbon atoms, and alkyl group having one to three carbon atoms; and, if required, one or more halides as a secondary component. The use of such etching solution results in an accelerated etching rate.

Selective plasma etching of organic materials employing photolithographic techniques

Abstract: A method is disclosed for selective plasma etching an organic material. Etching is achieved by means of a low temperature plasma which reacts with the organic material through an apertured mask overlaying said material. The invention has particular application to electronic circuit fabrication. A large magnitude, alternating electric field is applied to a reaction chamber for generating an intense low temperature plasma in the region of the organic material. A preferred organic material is a polymer of fluorinated ethylene propylene and a suitable mask is a photoresist composition.

Encoding of read only memory by laser vaporization

Abstract: A beam-lead silicon integrated circuit read-only memory is made in a conventional manner by forming an array of transistors on a silicon substrate, except that the gold portion of one conductive lead to each memory cell is severed, as by gold etching. Conductive connection to each memory cell is, however, maintained by the platinum-titanium intermediate layer that underlays the gold conductor. The array is permanently encoded by selectively vaporizing, with a laser beam, the exposed platinum layer of certain memory cells. This technique permits laser encoding of a beam-lead silicon integrated circuit with a sufficiently low power beam as not to endanger the silicon substrate.

The Fe−3Si steel etching technique for local strain measurement

Abstract: The Fe−3Si steel etching technique for measuring localized plastic deformation is described. The technique is well suited for revealing plastic strain in the vicinity of notches, cracks and other stress concentrations, both on the micro- and macroscale. The method is capable of yielding quantitative information about the strain distribution on the surface and in the interior of test specimens whose plastic-flow properties model the behavior of engineering alloys, in general, and low- and medium-strength steels, in particular. Methods of melting and fabricating the steel for this purpose, specimen preparation, and metallographic procedures are explained. Mechanical properties of the steel and its special etching response are described. In addition, results of some plastic-zone determinations are presented to illustrate the technique's capabilities, and other applications are mentioned.

Method for manufacturing a semiconductor photosensitive device

Abstract: A method for manufacturing thin semiconductor photosensitive devices having a flat surface comprising the steps depositing a high resistivity silicon epitaxial growth layer on a low resistivity silicon substrate, forming a plurality of PN junctions in the growth layer and etching the substrate to remove the central portion thereof so as to expose the corresponding flat surface portion of the growth layer with an etchant of HF, HNO3 and CH3COOH which selectively etches the low resistivity silicon without etching the high resistivity silicon.

Aluminum etching solution

Abstract: An etching bath, useful in the fabrication of hybrid thin film and silicon monolithic semiconductor devices, for removing aluminum film which is unprotected by an overlying photoresist. The bath includes the conventional combination of phosphoric, nitric, and acetic acids, to which is added about 2 1/4 grams of sucrose per 100 ml of etch solution. Addition of the sucrose substantially reduces undercutting and improves resistance to over-etching.

Detection of Fast Neutrons by Etch-Pit Method of Nuclear Track Registration in Plastics

Abstract: Plastics, such as polycarbonate, cellulose nitrate and cellulose acetate were irradiated with fast neutrons (2.5, 14 MeV) and a count was made of the number of etch-pits on the surfaces of the irradiated material after etching with suitable chemical reagents. The experiments proved that the number of etch-pits increases with the etching time, and that at least during the early period of etching, a close correlation seems to exist between ΔP the increment in the number of etch-pits per unit area and Δl the increment of thickness of layer removed for a common increment of etching time Δt. In other words, an approximate relation ΔP/Δl=ρ was observed to hold during this early etching period, ρ being a constant that seems to correspond to the number of etchable damages produced by fast neutron irradiation per unit volume. The value of ρ was found to correspond roughly to the estimated number of recoil carbon and oxygen atoms in a unit volume in the case of polycarbonate which consists of carbon, oxygen and hyd...

Method of continuously etching a silicon substrate

Abstract: A silicon substrate is continuously etched by exposing the top surface of the silicon substrate in a closed chamber at a low temperature to a chemical vapor environment of nitric oxide, hydrogen fluoride, water and oxygen. This invention relates in general to the art of treating a silicon substrate and in particular, to a method of continuously etching a silicon substrate to any desired depth.

Manufacture of semiconductor devices

Abstract: A method of manufacturing a semiconductor device comprising the steps of providing a plate-shaped semiconductor body, removing by spark erosion a first portion of the semiconductor body, and then using a selective etching process to remove only a second portion of the semiconductor body.

Method for fabricating semiconductor devices

Abstract: A plurality of individual semiconductor devices are simultaneously produced by thinning a doped semiconductor wafer to a desired uniform thickness, thermocompression bonding the thinned semiconductor wafer to a metal support plate, etching the wafer into many tiny discrete members, and punching out small individual sections of the support plate, each section forming a heat sink and having one of the bonded semiconductor members thereon Alternately, the semiconductor wafer may be thinned after the bonding step has been effected, although prior thinning is preferred