Abstract: A low temperature method of fabricating conductive (3.5 Ω/ sq.) p+/n junction diodes possessing excellent I-V characteristics with reverse-bias leakage less than -3 nA.cm-2at -5 V is described. Single crystal n-type 〈100〉 Si is implanted with 60 keV11B + through 0.028-µm thick sputtered Ti film. Rapid thermal annealing (RTA) in an N 2 ambient simultaneously forms a 0.36-µm deep p+/n junction and a 0.063-µm thick bilayer of TiN and TiSi 2 with a resistivity of 22 µΩ.cm. The electrical properties of these diodes are not degraded by annealing for 30 min at 500°C, suggesting that the outer layer of TiN is an effective diffusion barrier between TiSi 2 and Al.

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. Normally this conductive layer is stripped to avoid shorting out devices. However, the present invention patterns this conductive layer, thereby providing a local interconnect with the sheet resistance of the order of one ohm per square. 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 level fulfills all of the functions which a buried contact layer could fulfill, and fulfills other functions as well.

Abstract: The diffusion of Al in polycrystalline ion‐implanted α‐Ti has been studied in the temperature range 600–850 °C using ion‐beam techniques. Diffusion couples were created by ion implantation. The time‐dependent concentration profiles were monitored by the use of the nuclear resonance broadening technique through the 27Al(p,γ) 28Si reaction. The effect of the implantation energy and implanted dose on the diffusivity of Al has been investigated. The value of 1.62±0.11 eV for the activation energy and (7.4±9.8)×10−7 cm2/s for the frequency factor was obtained. The present result is discussed in the framework of the Ti diffusion barrier used in semiconductors.

Abstract: TiN films are prepared by N+2 implantation onto evaporated Ti films. By properly selecting the Ti thickness, implantation energy and annealing process, a TiSi2/TiN structure can be formed. In particular, in this work a postimplant rapid isothermal annealing is carried out at 800 °C for 30 s by using an electron beam. The effectiveness of these TiN films as a diffusion barrier is then evaluated when put in contact with a thick Al overlayer. Both the TiN/Al and TiSi2/TiN/Al contact structures are tested, after thermal treatments up to 600 °C, on shallow junction diodes and four terminal resistor test patterns for contact resistance measurements. The electrical performances of the TiSi2/TiN/Al contact system are found to be good, although the degradation resistance is slightly worse than the one observed on similar structures annealed in a vacuum furnace after the nitrogen implantation.

Abstract: Self‐supporting films of amorphous Cu20Ta80 alloys have a crystallization temperature as high as 800 °C, yet they fail as diffusion barriers in aluminum‐silicon contacts at much lower temperature because of compound formation. On Si(100) the a‐Cu20Ta80 films react above the temperature at which TaSi2 forms (650 °C). In contact with aluminum, Al3Ta starts to form at 500 °C, which is also the failure temperature of a‐Cu20T80 as diffusion barrier between Al and Si(100). The reaction characteristics of the barrier constituents with the surrounding elements as well as the crystallization temperature determine the thermal stability of amorphous alloy diffusion barriers.

Abstract: We have used a reactively sputtered TiN diffusion barrier to prevent interpenetration of a (Ni)GeAuPt ohmic contact layer and Ti/Pt/Au overlay on GaAs devices baked at 250-300°C in air. Planar GaAs MESFET's and TLM patterns were fabricated and iteratively tested and baked. Devices without TiN showed severe degradation in morphology and dc and RF performance. Devices with TiN remained essentially unchanged.

Abstract: Titanium carbonitride has been discovered to be an effective diffusion barrier material for use in metallization structure for MOS integrated-circuit devices. A layer of the material (24) deposited under aluminum (22) prevents deleterious aluminum-silicon or aluminum-silicide interactions.

Abstract: A new MOS technology with the following advantages has been investigated: TiSi 2 is formed by being self-aligned to source and drain regions by silicidation; and TiN is formed by self-aligned to contact regions by direct nitridation. TiSi 2 was prepared by two-step annealing to only form silicide on the diffused layers. TiN was formed by direct nitridation of TiSi 2 in N 2 at a temperature higher than 900 °C. The TiN formed using this method was found to be an effective diffusion barrier between Al and Si for annealing at up to 500 °C for 1 hour. PSG-cap annealing provided excellent p-n junction characteristics with a silicide layer of 4 Ω/□ even after annealing at 950 °C for 30 min. Characteristics of devices fabricated by this new technology were demonstrated.

Abstract: PURPOSE: To obtain an electrode having excellent heat resistance, by repeatedly depositing laminated layers of diffusion barrier layers and soft metal layers, whose thicknesses are controlled so as not to yield cracks, on an ohmic connecting layer on a compound semiconductor substrate. CONSTITUTION: Mo 32 is evaporated on a P-type GaAs substrate 31. The Mo 32 also serves the role of a barrier for preventing external diffusion of Ga and As from an ohmic electrode and the substrate. Then, soft metal Au 33 is evaporated in a vacuum. An Mo diffusion preventing film 34, an Au film 35, an Mo diffusion preventing film 36 and an Au film 37 are evaporated in a vacuum. Thus an ohmic electrode is completed. In this way, the diffusion preventing Mo film is divided into a plurality of layers. The thickness of each layer is controlled so that cracks are not yielded in heat treatment during alloy processing and element processes. Then, the electrode having an excellent barrier effect and heat resistance is obtained. COPYRIGHT: (C)1986,JPO&Japio

Abstract: A process for making complementary transistor devices in an epitaxial layer of a first conductivity type having a deep vertical isolation sidewall between the N and P channel transistors by providing a backfilled cavity 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 in contact with the epitaxial layer and overcoated with an isolation and diffusion barrier layer, the second silicate layer doped to a conductivity opposite to that of the first layer and isolated therefrom by said isolation and diffusion barrier material. The cavity is backfilled with semiconductor material of a conductivity type opposite to that of the epitaxial layer and during this backfilling operation the dopants in the first and second layer outdiffuse into the epitaxial layer and into the backfill material respectfully to prevent the creations of parasitic channels.

Abstract: We have examined the thermal stability of Al–Si/TiSi2/Si Schottky diodes both with and without a sputter‐deposited W–Ti (10 wt. %) diffusion barrier after furnace annealing up to 550 °C, 30 min. The diodes having the diffusion barrier exhibit stable Schottky barrier heights up to 550 °C, 30 min. In contrast, after 450 °C, 30 min annealing, diodes which do not have a diffusion barrier exhibit Schottky barrier heights typical of Al/n‐Si. Metallurgical interactions have been investigated by He backscattering spectroscopy which shows a stable W–Ti/TiSi2 interface up to 550 °C, 30 min annealing in samples having the diffusion barrier. The samples without a diffusion barrier show evidence of Al–Ti interdiffusion after 450 °C, 30 min annealing. Residual gas incorporation in the barrier layers was investigated by Ar ion sputter‐depth profiling Auger electron spectroscopy. Sheet resistance measurements and x‐ray diffraction analysis were used to investigate intermetallic phase formation. Selective wet etching comb...

Abstract: A metallization scheme to form reproducible and stable ohmic contacts to GaAs is described. The approach is based on the configuration: GaAs/X/Y/Z; where X is a thin metal film (e.g. Pt, Ti, Pd, Ru), Y is an electrically conducting diffusion barrier layer (TiN, W, or W(0.7)N(0.3), and Z is a thick metal layer (e.g. Ag) typically required for bonding or soldering purposes. The value and reproducibility of the contact resistance in these metallization systems results from the uniform steady-state solid-phase reaction of the metal X with GaAs. The stability of the contacts is achieved by the diffusion barrier layer Y, which not only confines the reaction of X with GaAs, but also prevents the top metal layer Z from interfering with this reaction. Applications of such contacts in fabricating stable solar cells are also discussed.

Abstract: A new self-aligned procedure has been developed to connect polysilicon links on chip by using a CW argon laser. A silicon nitride mask serves as a diffusion barrier over part of the link during doping of the polysilicon, and later as an antireflection coating to couple the maximum amount of light into the undoped region during laser scanning. The laser melts this region only and dopant atoms rapidly diffuse in from the neighboring parts of the link. For the optimum mask length, 100 percent of the links were open circuits ( >15 MΩ) before irradiation, while the sheet resistivity was reduced to 12 Ω after processing.

Abstract: The early stages of corrosion of AISI 314, HK 40, and Alloy 800H have been studied in a strongly carburizing (aC=08), weakly oxidizing\((P_{O_2 } = 10^{ - 30} bar)\) atmosphere at 1098 K Samples with electropolished and cold-worked surfaces were exposed for up to 400 min at temperature, in a conventional corrosion rig or in a reaction vessel which was installed within an X-ray photoelectron spectrometer The latter facility allowed the effects of the specimen heating rate and the rat of gas flow to be investigated Examination of the corrosion products was accomplished with the aid of XPS, SEM, TEM, and conventional metallography Initially, surface layers comprised of α-Cr2O3, (Mn, Cr)3O4, and SiO2 formed, with layer structure, microstructure, and composition being functions of alloy composition and surface condition Only on the cold-worked surfaces did a well-developed duplex oxide, consisting of an outer, Cr-rich oxide layer and an inner, SiO2 layer, form In good agreement with the predicted value of 19 wt%, between 14 and 2 wt% Si in the alloy was required to form a complete SiO2 layer After an incubation period, α-Cr2O3 became unstable and transformed to M7C3; the carbides then grew by diffusion of metal from the alloy substrate The presence of manganese, as (Mn, Cr)3O4, in the surface oxide influenced the mode of carbide growth, whereas the rate of carbide growth was severely suppressed by a continuous SiO2 layer which acted as a diffusion barrier both to metal and to carbon It is argued that the SiO2 layer is most effective in reducing carburization when it is free from or contains very few structural defects

Abstract: In order to prevent diffusion of silicon into aluminium metallisation (7) from an underlaying silicon region (2) a titanium nitride diffusion barrier layer (6) is provided, in a self-aligned manner, at a window (3) in an oxide layer (1) over the silicon. The process involves depositing titanium (4) over the oxide (1) and in the window (3), annealing to cause titanium disilicide (5) to be formed in the window, removing unreacted titanium (4) and annealing in nitrogen to convert the titanium disilicide (5) to titanium nitride (6). Metallisation (7) of pure aluminium is subsequently applied and patterned as appropriate.

Abstract: A method of coating a metal substrate with a ternary or greater alloy of aredetermined composition is disclosed. Initially, a first and second metals are electrodeposited on the substrate using an aqueous electrolyte. At least one metal powder is simultaneously mixed in the electrolyte as the first and second metals are electrodeposited so that a portion of the metal powder is occluded in the electrodeposited metal coating. The rate of occlusion of the metal powder is controlled by the volume percent of the metal powder in the electrolyte. Finally, the metal coating and substrate are heat treated to diffuse the occluded metal powder in the coating and to form the desired alloy coating. A plurality of metal powders can be mixed in the electrolyte according to the present method. In addition, a diffusion barrier coating can be initially provided on the metal substrate. The method is particularly useful with iron-based metals such as stainless steel. The rate of occlusion of the metal powder is additionally controlled for iron-based metals using an iron-nickel plating solution by controlling the presence of reducible ferrous ions. The microstructure of the electrodeposited coating also affects the occlusion rate. The rate of occlusion was also increased by varying the current density.

Abstract: 1. Radiation-emitting semiconductor diode having a small-area contact, suitable for the connection of a glass fibre (41) as light guide, having a substrate body (10) and a semiconductor layer structure (11) and, situated on the surface of the layer structure, contact consisting of several metal layers, of which one layer (15) is made of gold and another layer (14) is made of a metal that acts as diffusion barrier for gold, and the region of the layer structure which is made of semiconductor material and which lies outside the junction of the small-area contact being made highly resistive by means of implantation, characterized in that the layer (14) provided as diffusion barrier for the gold of the contact (115) extends as large-area surface protection layer over the region (31) of the layer structure (11) made highly resistive.

Abstract: A method of preventing the diffusion of an element out of the material of an optical waveguide substrate during thermal diffusion of a deposited pattern of dopant material into the substrate comprising the step of providing the substrate with a diffusion barrier layer after deposition of the dopant material pattern but prior to the thermal diffusion.

Abstract: 600‐keV Bi was implanted into an Al/Ti bilayer structure. There is good agreement between the Bi depth profile measured by Rutherford backscattering and corresponding theoretical prediction (Monte Carlo code trim). After annealing at low temperatures, the pronounced structure of Bi concentration at the Al/Ti interface vanishes, and the buildup of a surface precipitation is observed. At 500 °C annealing, strong Bi diffusion sets in, associated with the intermixing of the substrate components. A thin oxide layer present at the surface acts as a diffusion barrier for Bi, resulting in Bi segregation at the oxide/alloy interface.

Abstract: An aluminum-stabilized superconducting wire comprises an aluminum member, a copper member, and a first diffusion barrier layer formed between the aluminum member and the copper member. The copper member contains a plurality of bundles each having a multiplicity of fine filaments of Nb3Sn embedded in a copper alloy and a second diffusion barrier layer surrounding the copper alloy. Preferably, the ratio m in the cross-sectional areas between the first diffusion barrier layer and the aluminum member is selected to meet the condition of 0.03