Abstract: A protective diffusion barrier for metalized mirror structures is provided by a layer or coating of silicon nitride which is a very dense, transparent, dielectric material that is impervious to water, alkali, and other impurities and corrosive substances that typically attack the metal layers of mirrors and cause degradation of the mirrors' reflectivity. The silicon nitride layer can be deposited on the substrate before metal deposition to stabilize the metal/substrate interface, and it can be deposited over the metal to encapsulate it and protect the metal from corrosion or other degradation. Mirrors coated with silicon nitride according to this invention can also be used as front surface mirrors.

Abstract: In an ultrahigh vacuum (UHV) environment, thin poly crystalline Ni films have been deposited on a Zr (112) single-crystal surface. In contrast to the case of poly crystalline Ni and Zr films, formation of amorphous Ni—Zr is not observed upon annealing at 300 °C for 11.5 h. The possible presence of an oxide or an amorphous phase diffusion barrier is ruled out and therefore the lack of a reaction must be due to a reaction barrier at the single-crystal Zr/ Ni interface. Either ion mixing of the interface with 400 keV, 5 × 1015 Xe+ /cm2, or deposition of a poly crystalline Zr layer in between the Zr single crystal and the Ni overlayer can overcome this reaction barrier. These results indicate that grain boundaries in polycrystalline Zr play an important role in amorphous Ni—Zr formation by a solid-state reaction.

Abstract: A local interconnect system for VLSI integrated circuits During self-aligned silicidation of exposed moat and gate regions in a nitrogen atmosphere, a conductive titanium nitride layer is formed overall A second titanium layer is then deposited overall and again reacted, to thicken the nitride layer without increasing the thickness of the silicide layers This conductive layer is patterned and etched to provide local interconnects with a sheet resistance of the order to ten ohms per square, and also etch stops Moreover, this local interconnect level permits contacts to be misaligned with the moat boundary, since the titanium nitride local interconnect layer can be overlapped from the moat up on to the field oxide to provide a bottom contact and diffusion barrier for a contact hole which is subsequently etched through the interlevel oxide This local interconnect capability fulfills all of the functions which a buried contact capability fulfill, and fulfills other functions as well

Abstract: Properties of silicon oxynitride films on substrates formed by plasma‐enhanced chemical vapor deposition (PECVD) employed as diffusion barriers have been reported. The relation between the refractive index and the composition of films, the thermal stability and the barrier ability to Zn impurity diffusion have been discussed; and we propose an optimum range of the refractive index of the PECVD films for excellent diffusion barriers and a suitable structure for selective diffusion barriers.

Abstract: Copper-tin intermetallic compounds readily form when tin-bearing solder connections are made to copper surfaces. These compounds continue to grow during the life of solder connections and represent potentially weak interfaces. An investigation was undertaken to determine if a diffusion barrier between the solder and copper would inhibit Cu-Sn intermetallic compound formation and thereby extend joint life. Hybrid integrated circuit solder connections formed between external clip-on terminals and Ti-Pd-Cu-Ni-Au (TPCNA) thin-film terminations were investigated. The terminals had 60wt%Sn-40wt%Pb solder clad on the circuit-gripping surfaces of phosphor-bronze clips. The diffusion barrier consisted of an electroplated Ni layer on the phosphorbronze underneath the solder. The mechanical strength of solder connections formed using terminals with and without a Ni barrier were compared by measuring joint strength both initially and after temperature cycling and accelerated temperature aging. Joint metallographic cross sections and fracture interfaces after pull testing were analyzed to determine how effectively the Ni layer isolated Sn in the solder from Cu in the phosphor-bronze. SEM analysis confirmed that 1-um-thick Ni provides an effective diffusion barrier. Consequently, strength of 60n40Pb solder connections formed between phosphor-bronze clip-on terminals and TPCNA thin-film terminations were markedly increased, particularly at elevated temperatures up to 150°C.

Abstract: Diffusion barrier properties of selective chemical vapor deposited (CVD) tungsten to silicon and aluminum interdiffusion have been investigated using secondary ion mass spectroscopy, x‐ray diffraction analysis, and scanning electron microscopy. Samples of titanium layered pure aluminum on selective CVD tungsten on cleaned silicon wafers were prepared and sintered between 450 and 520 °C. The Ti layered aluminum was used to increase the capacity for silicon to facilitate the outdiffusion from the substrate. Magnetron sputter deposited Ti:W samples were also included in the analysis for comparison purposes. The experimental results indicated that 73 nm of selective tungsten with sheet resistance of 1.5 Ω/⧠ was sufficient as a diffusion barrier for both aluminum and silicon at 450 °C for 30 min, but failed at 520 °C for 30 min. 33 nm thick selective tungsten with 7 Ω/⧠ sheet resistance failed to prevent interdiffusion of aluminum and silicon even at 450 °C for 30 min. 100 nm of Ti:W remained an excellent diff...

Abstract: To securely attach a narrow line width electrodeposited layer of gold to an underlying semiconductor structure a thin multiphase adhesion film of nitrogen-modified titanium is formed between a titanium nitride diffusion barrier layer and an overlying gold seed layer. This additional layer nitrogen-modified titanium layer provides a titanium base to ensure adhesion of the gold, yet contains sufficient nitrogen interstitially dispersed in the thin titanium film to prevent formation of unetchable gold-titanium compounds.

Abstract: A method for the prevention of dopant diffusion from the back side (24) of a doped semiconductor substrate (20) during epitaxial layer (38) growth. The entire surface of the substrate (20) is first covered with a cleanly etchable material (26). Around the entire first layer (26) is formed a second dopant diffusion barrier layer (32). The front sides (28) and (34) of the layers (26) and (32) are then selectively etched away to expose the front side (22) of the substrate (20) upon which the epitaxial layer (38) will be grown without contamination of dopant diffusion from the sealed back side of the substrate (20).

Abstract: Ni 2 P is a metallic conductor with a bulk resistivity of 32 µΩ . cm. Films of Ni 2 P can be sputter-deposited in both the amorphous and crystalline forms by varying the sputtering parameters. The amorphous to crystalline transition has been found to take place at about 250 °C and sufficient grain growth to exhibit X-ray reflections takes place by 400 °C. In both forms, films of Ni 2 P have been found to form ohmic contacts to n-InP (Sn doped 2 × 1018cm-3) p-InGaAs (Zn-doped 8 × 1018cm-3) with sufficiently low sheet resistivity and specific contact resistance to be useful as a metallization layer in most devices. It was also found that up to 400 °C, amorphous (as sputtered) films of Ni 2 P function as efficient diffusion barriers between an outer Au layer and the III-V substrate. It is possible, therefore, for amorphous (as sputtered) films of Ni 2 P to function simultaneously both as a metallization layer and diffusion barrier.

Abstract: Titanium nitride is of interest for IC fabrication because of its excellent performance as a metallic diffusion barrier. TiN films have been deposited in a batch sputtering system equipped with dc magnetron cathodes, rf substrate bias, and independently controlled Ar and N2 sources. A threshold value of N2 flow exists, above which nitridation of the Ti target face is believed to occur. Operation above this threshold results in lower deposition rate and higher cathode voltage. It is demonstrated that high quality films can be deposited at N2 flows below the target nitridation threshold, resulting in an approximate threefold improvement in deposition rate. As‐deposited films on (100) silicon have resistivities of 50–60 μΩ cm and moderate compressive stress. rf substrate bias is required to achieve these resistivities; excess bias increases compressive stress. RBS profiles of deposited films show low levels of oxygen contamination and nominally stoichiometric films over a considerable range of deposition con...

Abstract: An integrated semiconductor circuit consisting of a silicon substrate having an impurity doped circuit therein, and a layer of silicon dioxide formed on the substrate and having a contact hole therein overlying the circuit. An outer contact interconnect level composed of aluminum or an aluminum alloy provides electrical contact to the circuit. A tantalum disilicide diffusion barrier layer is disposed between the circuit and the interconnect level, with a layer of substantially pure tantalum both above and below the tantalum disilicide diffusion barrier layer.

Abstract: An investigation of the thermal stability and Schottky behavior of Ti‐W thin film contacts to n‐Si in the presence of an Al overlayer is reported. Rutherford backscattering spectroscopy, glancing‐incidence x‐ray diffraction, and current‐voltage measurements were used to characterize the multilayer contact structures. The low Schottky barrier height, 0.51 eV, of the Al/Ti80W20/n‐Si structure was repeatedly measured after 30‐min anneals up to 500 °C. This stability was improved to 600 °C when a diffusion barrier layer of Ti30W70 alloy was included. The detection and significance of Al penetration in low Schottky barrier height contacts to Si have been discussed.

Abstract: An integrated circuit device including a link point for electrically connecting a plurality of metal layers, comprising a first metal layer, a link insulating layer and a second metal layer. Diffusion barrier may be employed between the link insulator layer and each of the first metal layer and the second metal layer. The metal layers are connected by exposing the link point to a low-power laser for a relatively long pulse width.

Abstract: PURPOSE: To produce a terminal for connectors having excellent corrosion resistance and reliability by providing an Ni plating layer and Sn-Ni alloy plating layer successively over the entire surface of a copper alloy base material and further, providing a gold plating layer on at least the surface to serve as a contact. CONSTITUTION: The Ni plating layer 3 is provided as a diffusion barrier of copper over the entire surface of the base body 2 consisting of a copper alloy and the Sn-Ni alloy plating layer 4 as the diffusion barrier for copper and for impartation of corrosion resistance is provided over the entire surface of the Ni plating layer 3. The thickness of the Ni plating layer 3 and the Sn-Ni alloy layer 4 is 1W4μ in total and the thickness of the Sn-Ni alloy layer 4 is 0.1W0.5μ. The content of Sn in the Sn-Ni alloy layer 4 is preferably 50W80wt%. The gold plating layer 5 is provided at about 0.1W1μ film thickness on the surface of the Sn-Ni layer 4, at least on the surface of the contact part 6. The terminal 1 for connectors is thereby formed with the high economic efficiency. COPYRIGHT: (C)1988,JPO&Japio

Abstract: The present invention provides an intermetallic compound-based, composite superconductor suitable for use in superconducting coils for a high magnetic field, where the superconductive part is formed by thermal diffusion reaction, and which has such a structure that a metal layer of high melting point and high resistance is provided at the outermost periphery of a strand comprising a plurality of filaments containing a superconductive compound formed by diffusion reaction with the surrounding matrix, a stabilizer surrounding the matrix, and a diffusion barrier provided between the stabilizer and the matrix for preventing diffusion of superconductive compound-forming element in the matrix from diffusion into the stabilizer during the diffusion reaction, and the coupling current induced between the intermetallic compound-based superconductive wire members can be reduced by the provision of the metal layer of high melting point and high resistance. Furthermore, the superconductive parts can be formed by heat treatment, and the AC loss can be reduced thereby.

Abstract: A diffusion triple with copper and nickel sandwiching a thin diffusion barrier layer of silver was annealed for various times at 760 °C. Silver exhibits a limited solubility (0.135 atom fraction) for copper and a slight (0.01) solubility for nickel at 760 °C. The Ag barrier was breached by successive processes of Cu interdiffusion, interface instability of the Ag-Ni interface, and growth of Cu-Ni protrusions from the Ag-Ni interface to ultimately bridge the Ag barrier. The kinetics of widening of the Ag barrier were determined and interpreted in terms of the diffusion concentration profiles and the plastic deformation of the Ag barrier by the Cu-Ni protrusions.

Abstract: The stability of the reactively sputtered titanium carbide film sandwiched between cobalt disilicide and aluminum has been studied using Rutherford backscattering, Auger electron spectroscopy, x‐ray diffraction, Nomarski optical and transmission electron microscopy. The titanium carbide film is an excellent diffusion barrier through heat treatments at temperatures up to 450 °C for an anneal time of 30 min. The barrier breaks down at 500 °C. Co2Al9 and Ti7Al5Si12 compounds were formed when annealed at 550 °C.

Abstract: Schottky‐barrier diodes have been fabricated by evaporation of Pt on Si substrates followed by annealing at 500 °C to yield PtSi. Then V and Al were evaporated. The amount of oxygen intentionally incorporated in the V film during deposition was varied and the resulting effect on the diffusion barrier action of the vanadium film has been studied by I‐V and C‐V measurements of the diodes and by backscattering spectrometry of simultaneously prepared test samples. It is found that for V films with low oxygen concentrations annealing in the range 400–600 °C leads to the formation of VAl3 and subsequent barrier height change. For vanadium films containing 50‐at. % oxygen there is no observable reaction between V and Al and the barrier height is preserved for annealing between 400 and 600 °C.

Abstract: In making bipolar transistors, an interfacial oxide layer (5) is formed over ther monocrystalline region (1), and polysilicon (6) is formed both thereon as an extrinsic emitter region. After doping the polysilicon a monocrystalline emitter region (4) is produced in the base region by diffusion from the extrinsic polysilicon emitter region. The oxide layer (5) acts as a diffusion barrier to ensure that excessive dopant does not reach the monocrystalline region. After the above operation, a thermal treatment is effected at a higher temperature, e.g. 1100° C., for a few seconds, which breaks down the interfacial oxide layer referred to above. This temporary use of the interfacial oxide layer leads to better and more consistant transistor characteristics.

Abstract: Process for reducing the water vapour diffusion in a plastics composite insulator consisting of several layers by incorporation of at least one mica-containing layer as diffusion barrier in the form of a surface or intermediate layer on at least one plastics body, constituting the composite insulator.

Abstract: The stability of Schottky barrier gates in GaAs MESFETS has been investigated to allow device processing at elevated temperatures. The incorporation of a Pt diffusion barrier into the TiAu structure gives stability of electrical characteristics up to 350°C and a Ti-W-Au contact is stable up to 400°C. To achieve higher temperature stability for use in a self aligned gate (SAG) technology, a more stable Schottky barrier material such as a TiW (30 at % Ti) alloy has been used. This has been found to be unreliable above 750°C and it has been found necessary to use a tungsten silicide contact W1.6Si (37 at % Si) to achieve reproducible Schottky contacts at the temperature used for ion implantation activation (800°C). SAGFETs have been fabricated using W1.6Si and initial results indicate good yields (91%), high gm (190 mS/mm) and good uniformity (standard deviation = 6.8% for 293 devices).

Abstract: Titanium nitride (TiN) films are prepared by implanting 40 keV N ions in silicon wafers coated with 60 and 80 nm thick titanium layers. These films are of interest as diffusion barriers in metal-lization schemes for very large scale integrated devices. After the implant, the specimens are annealed in vacuum either at 700 or 800°C, giving rise to the formation of a TiSi2 film at the TiN/Si interface in the 80 nm thick nitride layer. No such silicide film grows in the case of the 60 nm thick nitride layer. This phenomenon is related to the different concentrations of nitrogen at the TiN/Si interface in the two cases. Measurements of the nitrogen profile by electron energy loss spectroscopy (EELS), performed in a dedicated STEM on cross-sectioned specimens, shows that in the thicker films, where the TiSi2 formation occurs, the nitrogen concentration at the TiN/Si interface is lower than about 35 at%; this is, in turn, reported to be the threshold concen-tration for the formation of the stable f.c.c. phase of titanium nitride. The thinner nitride films are subsequently coated with an aluminium overlayer, about 1 μm thick, and then annealed in N2 at 600°C for 30 min; this treatment is known from previous works to result in the degradation of the diffusion barrier. The corresponding morphology of this Al/TiN/Si structure and the nitrogen profile are presented.

Abstract: A process for making complementary transistor devices - (11, 12) in an epitaxial layer (14) of a first conductivity type having a deep vertical isolation sidewall (21) between the N and P channel transistors by providing a backfilled cavity - (26) in the epitaxial layer, the sidewalls of the cavity being coated with layers of material, the first layer being a silicate doped with the same conductivity type as the epitaxial layer (14) and in contact with the epitaxial layer. The first layer is overcoated with an isolation and diffusion barrier layer (21). A second silicate layer is provided which is doped to a conductivity opposite to that of the first layer and isolated therefrom by said isolation and diffusion barrier material (21). The cavity (26) is backfilled with semiconductor material of a conductivity type opposite to that of the epitaxial layer (14) and during this backfilling operation the dopants in the first and second layer outdiffuse into the epitaxial layer and into the backfill material, respectively, to prevent the creation of oarasitic channels.

Abstract: A device comprises a UV radiation source and a reflector. The reflector preferably consists of two parabolic or elliptical half- shells. One or more coatings for the reflection of UV radiation and, underneath, a coating for absorbing the longer-wavelength part of the spectrum of the UV radiation source are provided on the reflector surface. A diffusion barrier layer is arranged between these coatings. The reflection layer consists of alternately low-refracting dielectric layers of SiO2 and high-refracting layers of HfO2, the diffusion barrier layer consists of a dielectric layer of SiO2 having a physical thickness of at least 0.5 mu and the absorption layer consists of a black anodically oxidised layer, black chromium- or nickel-plating, anodisation or bronzing of a polished copper coating or nickel coating of the reflector body consisting of aluminium alloy.

Abstract: Klystrons manufactured at the Stanford Linear Accelerator Center are typically baked at temperatures of 550 °C for times as long as 200 h. During these long bakeouts the copper‐gasketed type 304 stainless steel flange joints (seven in all) diffusion bond so intimately that the flanges can be separated only with a jacking fixture, and copper is left on the sealing surfaces. Removal of this copper necessitates the use of abrasive materials, which can result in contamination of the klystron body and compromise its reuse. We report on the use of 50 and 150 A TiN thin films as a diffusion barrier between the Cu gasket and the stainless‐steel flange.

Abstract: Die Erfindung betrifft eine integrierte Halbleiterschaltung mit einer aus Aluminium oder einer Aluminiumlegierung bestehenden Kontaktleiterbahnebene und einer als Diffusionsbarriere wirkenden Tantalsilizid-Zwischenschicht (4). The invention relates to a semiconductor integrated circuit including a group consisting of aluminum or an aluminum alloy contact conductor path plane and acting as a diffusion barrier tantalum oxide intermediate layer (4). Diese Zwischenschicht (4) zwischen der auseren Kontaktleiterbahnebene (3) und den diffundierten Bereichen (2) im Siliziumsubstrat (1), die einen uber der Stochiometrie der Verbindung liegenden Tantalgehalt aufweist, wird beidseitig von je einer reinen Tantalschicht (5, 6) erganzt. This intermediate layer (4) between the outer contact conductor path plane (3) and the diffused regions (2) in the silicon substrate (1) having a tantalum content lying above the stoichiometry of the compound is on both sides by a pure tantalum layer (5, 6) supplemented. Dabei liegt die Schichtdicke der ersten Tantalschicht (5) im Bereich kleiner 5 nm und die Schichtdicke der Tantalsilizidschicht kleiner 200 nm. Die erfindungsgemase Schichtenkombination Tantal/Tantalsilizid/Tantal (5, 4, 6) wirkt gleichzeitig als Diffusionsbarriere und hochstabiles Kontaktmaterial. The layer thickness of the first tantalum layer (5) in the range less than 5 nm and the layer thickness of the tantalum silicide layer of less than 200 nm. The layer combination of tantalum according to the invention / tantalum silicide / tantalum (5, 4, 6) simultaneously acts as a diffusion barrier and highly stable contact material. Durch diese Metallisierung (4, 5, 6) wird die Lebensdauer der elektrischen Leiterbahnen unter Temperatur-und Strombelastung sowie die Zuverlassigkeit der Kontakte bei VLSI-Bauelementen wesentlich verbessert. By this metallization (4, 5, 6), the life of the electrical conductor tracks under temperature and current load, and the reliability of the contacts in VLSI devices substantially improved.