Showing papers on "Silicon nitride published in 1969"

Charge Transport and Storage in Metal‐Nitride‐Oxide‐Silicon (MNOS) Structures

Abstract: A simple physical model that predicts charge accumulation at the dielectric interface of metal‐nitride‐oxide‐silicon (MNOS) structures is proposed and verified experimentally. The model is based on the presence of steady‐state current flow in the dielectric structure. Interface‐charge accumulation is shown to be determined by the requirement for continuity of current through the structure under steady‐state conditions. Continuity of current is established by accumulation of either positive or negative charge for a given polarity of charging voltage, depending on the relative current‐field characteristics of the silicon nitride and silicon dioxide layers. Due to the exponential nature of the current‐field characteristics, the time required to reach steady state is a strong function of the applied charging voltage. This leads to the observed charge storage property of MNOS devices. The hysteresis characteristic observed in MNOS structures is shown to be time‐dependent with a tendency to merge into a single‐...

Diffusion of Nickel in Amorphous Silicon Dioxide and Silicon Nitride Films

Abstract: Nickel‐59 radiotracer has been used to determine nickel diffusion coefficients in amorphous silicon dioxide and silicon nitride films between 1100° and 1490°K. Nickel distribution has been found to be Fickian with the calculated diffusivities obeying Arrhenius equation. Long diffusion times have been found to produce anomalous diffusivities in silicon nitride.

Process for forming a film on the surface of a substrate by a gas phase

Abstract: A process for forming a film on the surface of a substrate by a gas phase method in the presence of a catalyst used in the solid state electronics at a predetermined distance from the surface of the substrate on which the film is to be formed and a process for forming a silicon oxide or silicon nitride in the presence of a catalyst selected from the group comprising platinum and the like.

Charge storage model for variable threshold fet memory element

Abstract: A simple two‐layer model is presented for charge storage in a MI2I1S device in which the times for charging and discharging are expressed in closed‐form expressions depending on the conduction properties, the thicknesses, and the dielectric constants of the two layers. Data were taken using silicon oxide for I1 and silicon nitride for I2 which are in good agreement with the model. The model is quite general and should be valid for other insulators and other conduction mechanisms.

Oxidation Kinetics of Powdered Silicon Nitride

Abstract: The oxidation kinetics of powdered silicon nitride were studied in dry oxygen and dry air at 1 atm pressure between 1065° and 1340°C. An automatic recording electrobalance was used to measure the weight gain as a function of time. Parabolic oxidation kinetics were observed with an activation energy of 61 kcal/mol in dry oxygen and 68 kcal/mol in dry air. The oxidation rate in dry oxygen was approximately twice that in air. The solid oxidation product was tridymite above 1125°C and amorphous silica at 1067°C.

Some Properties of Vapor Deposited Silicon Nitride Films Obtained by the Reaction of SiBr4 and NH 3

Abstract: Silicon nitride films, easily etchable in buffered HF (75 Aa/min) and usable as gallium diffusion masks, are deposited at 800°C by the and reaction (ratio ) in a forming gas atmosphere. The chemical composition of the films, deposited between 500° and 800°C, as measured by chemical and electron microprobe analysis, is nearer to than to . The 800°C films are impervious to moisture. The room temperature stress in the films deposited on silicon is very high and cannot be lowered by decreasing the temperature of deposition or the ratio. The intrinsic stress of the films is highly tensile and is much higher than that in vapor deposited films: germanium wafers tend to warp with formation of slip lines. Films of composition containing—NH groups are obtained at 800°C when the ratio of .

Some Properties of Silicon Nitride Films Produced by Radio Frequency Glow Discharge Reaction of Silane and Nitrogen

Abstract: Silicon nitride films are deposited on silicon wafer at low temperature by radio frequency glow discharge reaction of silane and nitrogen. The main peak position of infrared transmission spectra, the growth rate and the etch rate of the nitride films change respectively from 870 to 820 cm-1, from 0.8 to 6.5A/sec and from 150 to 5A/sec in 15% HF etchant with changing silane concentration from 0.1 to 2.5 mol %. The etch rate is larger than that of the thermally grown silicon nitride. The dielectric constant of nitride films changes from 8 to 5 with changing substrate temperature from 500 to 25°C. The nitride film deposited at as high temperature as 500°C shows a large hysteresis of C–V curve. The silicon nitride film deposited at the substrate temperature of 300°C and at the silane concentration of 0.5 mol % is stable against B–T treatment as well as thermally grown silicon nitride films. The value of flat-band surface charge ranges from 7 to 14×10''/cm2, the value is relatively small in comparison with that of thermally grown nitride.

Switching and storage characteristics of MIS memory transistors

Abstract: Transistors with memory hawe been constructed in the form of MIS field-effect transistors in which the gate insulator consists of a double layer. Closest to the silicon is a silicon dioxide layer, no more than 15A thick. The importance of this layer will be discussed. It is covered by another layer, which may be silicon nitride, 200-800A thick. Aluminum oxide and silicon dioxide have also been tried as the second layer. At the interface between these two insulator layers, and at an energy level inside the silicon forbidden band, are traps with a density as high as 2×1014cm-2in the form of disorder states. These traps are donor type and may each give off an electron when the silicon is biased positively for a short time with respect to the insulator, turning the transistor ON. When the polarity is reversed the electrons are recaptured by the traps, neutralizing them and turning the transistor OFF. The charge transport is by tunneling.

Method for fabricating a semiconductor component for a semiconductor circuit

Abstract: A SILICON SUBSTRATE OF ONE CONDUCTIVITY TYPE COVERED WITH A SILICON NITRIDE MASKING LAYER HAVING AN APERTURE IS VAPOR-ETCHED TO HAVE A HOLLOW PART THEREIN AND THEN HEAT TREATED IN A MIXTURE GAS OF HCL, SICL4, H2 AND ONE ACTIVE IMPURITY WITH A SECOND CONDUCTIVITY TYPE OPPOSITE TO THAT OF THE SUBSTRATE, SO THAT A SILICON EPITAXIAL LAYER OF THE SECOND CONDUCTIVITY TYPE IS EPITAXIALLY GROWN ONLY ON THE SURFACE OF THE HOLLOW PART IN SUCH A MANNER TO REFILL THE HOLLOW PART, THEREBY MAKING THE SILICON EPITAXIAL LAYER OPERABLY AS A RESISTANCE ELEMENT IN THE SUBSTRATE WITH A PN JUNCTION FORMED THEREIN ACCORDING TO THIS METHOD.

PHASE STABILITY OF SILICON CARBIDE IN THE TERNARY SYSTEM Si-C-N

Abstract: After introductory remarks on advanced techniques for producing silicon carbide of high density and strength the phase stability of silicon carbide against nitrogen is discussed Thermodynamic calculations are in agreement with experimental results The stability of silicon nitride in contact with carbon is strongly pressure dependent In the temperature range between 2200°C and 2500°C nitrogen induces transformation of α-SiC into β-SiC Under suitable conditions the conversion can be forced repeatedly into both directions

Characterization, Control, and Use of Dielectric Charge Effects in Silicon Technology

Abstract: The charge behavior of dielectric films on silicon is particularly important in device and integrated circuit technology because of surface effects. Models for ionic migration, fixed-interface charge, and injection trapping are reviewed for insulators used in silicon technology: thermally-grown silicon dioxide and chemical vapor-deposited silicon dioxide and silicon nitride. The distinctive characteristics of insulator charge related to these mechanisms are applied in the case of reactively sputtered SiO2 and Ta2O5. Ion migration and injection-trapping behavior are found under certain conditions of preparation for both materials. A degree of interface charge control is indicated in the study of sputtered silicon dioxide. More work is needed to establish the future utility of these materials.

Method for isolating semiconductor devices from a wafer of semiconducting material

Abstract: AN ARRAY OF DEVICES IS FIRST FORMED IN A SILICON WAFER. A PROTECTIVE LAYER OF SILICON NITRIDE IS DEPOSITED ON THE SURFACE OF THE WAFER, AND A GLASS HANDLE BODY HAVING A THERMAL EXPANSION COEFFICIENT CLOSELY MATCHING THAT OF SILICON IS SEALED TO THE SILICON NITRIDE LAYER. THAT PORTION OF THE WAFER BETWEEN ADJACENT DEVICES IS ETCHED AWAY, AND A BODY OF A SOFTENED GLASS WHICH HAS A LIKE EXPANSION COEFFICIENT, BUT IS LESS REFRACTORY THAN THE GLASS HANDLE BODY, IS HOT-PRESSED INTO THE ARRAY OF ISOLATED DEVICES. THE HANDLE BODY IS THEN REMOVED BY ETCHING. D R A W I N G

Evaporation and thermodynamic properties of silicon nitride

Abstract: 1. We have studied evaporation of silicon nitride by the Langmuir and Knudsen methods in the range 1688–1773°K. It has been established that during evaporation this compound dissociates into silicon (solid or liquid, depending on the temperature) and nitrogen. 2. The rate of evaporation of Si3N4 depends on the area of the effusion orifice. 3. We have determined the equilibrium pressures of nitrogen above silicon nitride in the investigated range of temperatures, the evaporation coefficient of this compound, and its standard heat of formation from the elements by the second and third laws of thermodynamics.

Thin film dielectric materials for microelectronics

Abstract: Important applications of dielectric films used in modern integrated circuit technology include dielectric insulation, surface passivation, diffusion masking, radiation resistance, and hermetic seal These many functional applications pose stringent requirements on the various properties of the insulating films and the methods used for their preparation To date silicon dioxide (SiO 2 ) has been used almost exclusively because of 1) its ease of preparation, 2) its well-understood properties, and 3) its generally good compatibility and satisfactory interface with silicon There are, however, drawbacks to the use of SiO 2 and other materials have been sought for better performance, greater versatility, higher reliability, and lower cost These include binary metal oxides and silicon nitride The state of the art of thin film dielectric materials for microelectronics is reviewed in this paper The role of thin film dielectrics for devices is presented, and new and known materials are discussed for potential applications

Solid electrolytic capacitors having an additional insulated layer formed on the dielectric layer

Abstract: To improve the voltage breakdown and leakage current of solid electrolytic capacitors, the dielectric layer is reenforced by an additional layer of silicon nitride, silicon dioxide or increasing the thickness of the original dielectric layer.

Silicon nitride as a mask in phosphorus diffusion

Abstract: By means of tracer and activation experiments it is shown that during phosphorus diffusion in silicon nitride diffusion profiles are produced, which are very similar to the profiles in silicon dioxide processed in the same experiment. When oxygen was used as part of the carrier gas as is customary in semiconductor technology, a glass was produced in both cases which consisted of SiO2 and P2O5 and whose identity was proved by i.r. absorption and determination of the refractive index. When the medium does not contain oxygen, part of the nitride is transformed to silicon phosphide which is incorporated in the glass or escapes at higher temperatures. When oxygen is present, the silicon phosphide occurs briefly in an intermediate reaction. In this way the normal, slow oxidation of the nitride is accelerated and phosphorus pentoxide acts as a catalyst. The analogous formation of glass from oxide and nitride is the reason why silicon nitride exhibits a similar masking effect as silicon dioxide in phosphorus diffusion, even though it masks better than silicon dioxide against the diffusion of a number of other elements.

Pyrolytic deposition of silicon nitride films

Abstract: Silicon nitride films are prepared on graphite and other suitable substrates by the vapor phase pyrolysis of a silicon halide-ammonia adduct and preferably a silicon tetrafluorideammonia adduct (SiF4.2NH3).

Method of controllably oxidizing a silicon wafer

Abstract: The present invention relates to a method of growing an optimumthickness silicon dioxide layer for a nonvolatile metal-silicon nitride-silicon oxide-silicon field effect memory transistor near atmospheric pressure in a controllable manner. A silicon wafer, having source and drain regions therein, is placed within an epitaxial reactor through which an inert gas is then made to flow at a rate of 30 liters/minute. The silicon wafer is heated to 1,000* centigrade, and a 1.2-liter flow of oxygen is introduced into said epitaxial reactor for 15 minutes. The flow of oxygen gas is dispersed throughout the flow of the inert gas. The silicon crystal is slowly oxidized to form a 52.5-angstrom thick silicon dioxide layer thereon. When the selected time of oxidation has passed, the small flow of the oxygen into the epitaxial reactor is stopped. The total oxygen-inert flowing gas pressure in the epitaxial reactor is slightly above atmospheric pressure. A precise regulation of the thickness of a silicon dioxide layer grown on a silicon crystal is achieved by regulating the flow rate of oxygen relative to the flow rate of inert gas and regulating the oxidation temperature. The method of the present invention allows one to produce a 52.5-angstrom thick silicon dioxide layer on a silicon crystal. The 52.5-angstrom thick silicon dioxide layer is then covered with a 1,000-angstrom thick silicon nitride layer by chemical decomposition in the epitaxial reactor. A metal electrode in the silicon nitride layer and metal electrodes on the uncovered source and drain regions complete an MNOS field effect memory transistor which has very good switching characteristics.

The influence of impurities on the growth of silicon carbide crystals grown by gas-phase reactions

Abstract: The influence of impurities on the growth of silicon carbide crystals in chemical reactions was investigated An enhancement of filamentary growth and a stabilisation of the 2H and 4H structure by impurities was established Elongated, highly perfect crystals of several polytypes were obtained by directed vapour-liquid-solid growth The growth of filamentary silicon nitride crystals in the system SiO 2 -C-H 2 -N 2 was investigated and elongated highly perfect crystals of this material were obtained

Method of transferring a desired pattern in silicon to a substrate layer

Abstract: Methods for producing a desired pattern of retained and removed portions in a substrate layer of a material selected from the group consisting of silicon nitride, an oxide of silicon, and an oxynitride of silicon are disclosed. One method includes providing a transfer layer of silicon over the substrate layer, producing a pattern of removed and retained regions in the transfer layer and then etching the portions of the substrate layer exposed by the removed portions in the transfer layer with an etchant which etches the substrate layer without substantially etching the transfer layer to produce a pattern in the substrate layer substantially corresponding to that in the transfer layer. Other materials useful for transfer layers such as molybdenum, tungsten, nickel, chromium, and magnesium are also disclosed. Typical etchants for the various materials are also disclosed.

Distribution of sodium in silicon nitride

Abstract: The paper describes radiochemical examinations of the diffusion behaviour and content of sodium in single layer silicon nitride films and double layer silicon dioxide-silicon nitride films on silicon. The most significant result is that the sodium is gettered and enriched in the nitride in double layer films.

Effects of silicon nitride growth temperature on charge storage in the mnos structure

Abstract: Experimental results of the effects on charge storage in the MNOS structure by varying the growth temperature of the silicon nitride are presented. The range of growth temperature examined is 650–1100°C. The initial charge stored is positive at the lower temperatures, negative at the higher temperatures. The maximum positive charge that can be stored varies continuously with growth temperature. The ability to retain the stored charge when the charging voltage is removed decreases monotonically with increasing growth temperature.

Semiconductor element having surface coating and method of making the same

Abstract: A semiconductor element having a surface coating consisting of, for example, a silicon nitride film and a silicon oxide film covering different surface portions of a semiconductor substrate of, for example, silicon so that such surface coating can be utilized for selective diffusion of impurities such as gallium and antimony. In a semiconductor device thus formed, the surface coating acts as a satisfactory surface protective film against external atmosphere, and the backward characteristics of the PN junction can be improved because the end edge of the PN junction terminating at the substrate surface is covered with the silicon nitride film.

Heat seal of a glass member to another member

Abstract: The metal or semiconductor member is provided with a coating of silicon nitride and heat sealed to a glass member. The silicon nitride coating is readily wet by hot glass to form a rugged, vacuumtight seal.