Abstract: Material reactions as a result of thermal treatment were studied on thin‐film Al/silicide/Si systems with CoSi2, PtxNi1−xSi, and MoSi2 for the silicide. Auger electron spectroscopy and Rutherford backscattering analysis showed the transport of Si and the metal released from the silicide into the Al and transport of Al into the silicide. X‐ray diffraction showed the formation of Co2Al9 at 400 °C, PtAl2, NiAl3, and PtNiAl2 at 275 °C, of which the latter disappeared above 450 °C, and MoAl12 at 535 °C, as well as free Si. The Co2Al9 formation followed a linear time dependence with an activation energy of 2.3 eV. The MoAl12 formation followed a parabolic time dependence with an activation energy of 3.6 eV. A thin tungsten layer between Al and the silicide proved to be effective as a diffusion barrier below 500 °C, at which temperature WAl12 was formed. The microstructure was studied by scanning and transmission electron microscopy, electron microprobe analysis, and scanning Auger electron spectroscopy. The reaction resulted in the formation of Si islands with a size up to about 10 μm, containing Al‐rich inclusions, and the intermetallic compound with Si inclusions in between the islands.

Abstract: Contact reactions in the temperature range 250–650 °C between (100) Si and Pd‐W binary alloy films of composition Pd80W20 and Pd30W70 have been studied by a combination of ion backscattering, x‐ray diffraction, and current‐voltage measurement of Schottky barrier height. For the Pd‐rich alloy, the reaction around 400 °C produced the silicide Pd2Si by depleting Pd from the alloy and resulted in the formation of a two‐layer structure, W/Pd2Si/Si. We have found that the W layer has served effectively as a diffusion barrier for the subsequently deposited Al, indicating that a rectifying contact and its diffusion barrier can be fabricated simultaneously. At higher reaction temperatures, the W layer transforms to WSi2 with some mixture of Pd2Si. The alloying of Pd with W has been found to increase the formation temperature of Pd2Si but decrease that of WSi2. In the Pd80W20 reaction, Pd2Si forms around 400 °C and WSi2 around 500 °C. In the Pd30W70 reaction, Pd2Si forms around 500 °C and WSi2 around 650 °C.

Abstract: Thin film structures comprising a layer of aluminum and a material having a tendency to interact with aluminum are separated by an intermediate layer of aluminum having a high aluminum oxide content. The intermediate layer prevents said interaction by acting as a diffusion barrier. Preferred embodiments are directed to silicon semiconductor metallization structures, including Schottky barrier contacts, which comprise a bottom layer of tantalum, or other transition metal, or a metal silicide in contact with a silicon substrate, an intermediate layer of aluminum having a high aluminum oxide content and a top layer of aluminum. The intermediate layer functions as a diffusion barrier between aluminum and the metal, metal silicide or silicon. The preferred embodiments of the invention also includes the process for forming such structures preferably comprising: depositing pure tantalum under high vacuum in evaporation apparatus, substituting aluminum for tantalum in the evaporation apparatus and bleeding-in water, air or oxygen to form the aluminum oxide-rich intermediate aluminum layer and then returning to the high vacuum to deposit pure aluminum. The invention is also applicable to FET or CCD structures where a diffusion barrier for aluminum is required.

Abstract: An electrochemical measuring electrode has an ion-selective membrane and direct potential take off via an electron conductor. A diffusion barrier layer is provided between the membrane and the electron conductor for the purpose of reducing or eliminating the sensitivity to faults which can be caused by the presence of gases in a medium which is to be analyzed and into which the sensor is introduced. The diffusion barrier preferably comprises an ion-conducting solid-state body having a high diffusion resistance to oxygen.

Abstract: A new method for producing a self-aligned SBD guard ring, which uses a minimum of the device area, has been developed. The guard ring was achieved by a boron diffusion around a diffusion barrier such as molybdenum, through an undercut region at the diode periphery formed by the differential etching of a dual insulator (silicon nitride over thermal oxide).

Abstract: A compound material for temperatures up to about 1250° C. or 1350° C., respectively, and a method for producing the same, are disclosed, including a pair of joined layers one of which is a corrosion- and high-temperature-resistant alloy, the other layer consisting of a refractory material with high strength at high temperatures. The layer having the weaker mechanical strength at high temperatures is thinner than the other layer, the ratio of layer thickness preferably being between 1:5 and 1:2. A further alloy layer may be provided on the opposite side of the refractory layer, thereby to define a three-layer laminate. A thin layer of diffusion barrier material, such as platinum or palladium, may be provided between the refractory and alloy layers. The method for producing the laminate includes the step of detonating an explosive layer to exposively clad the alloy layer on to the refractory layer.

Abstract: The process comprises the following steps: (1) forming a glass sheet 34 which defines a substrate layer for the solar cell; (2) forming a diffusion barrier layer 36 on at least one surface of the substrate; (3) forming a first electrically-conductive layer 40 on the diffusion barrier, the first electrically conductive layer being a first electrode in the solar cell; (4) depositing small-grain polycrystalline silicon in a thin film 44, i.e. 10-100 micrometers, on the first electrode layer; (5) recrystallizing the deposited polycrystalline silicon until it reforms into large-grain polycrystalline or single-crystal silicon; (6) forming a PN junction 63 in the recrystallized silicon layer; and (7) forming a second electrically-conductive layer 62 on the recrystallized silicon layer, the second electrically-conductive layer being a second electrode in the solar cell. The solar cell produced by this process may be fabricated in large surface area configurations.

Abstract: Low-cost polycrystalline silicon solar cells supported on substrates are prepared by depositing successive layers of polycrystalline silicon containing appropriate dopants over supporting substrates of a member selected from the group consisting of metallurgical-grade polycrystalline silicon, graphite and steel coated with a diffusion barrier of silica, borosilicate, phosphosilicate, or mixtures thereof such that p-n junction devices are formed which effectively convert solar energy to electrical energy. To improve the conversion efficiency of the polycrystalline silicon solar cells, the crystallite size in the silicon is substantially increased by melting and solidifying a base layer of polycrystalline silicon before depositing the layers which form the p-n junction.

Abstract: In the centrifugal casting of bimetallic tube blanks by successive casting of a base layer with flux and a cladding layer, a layer of Ni, in amt. 2-3% (by wt. of the base layer), is cast on the surface of the base layer when it has cooled to about 100-200 degrees C below its solidus temp. and then the cladding layer is cast onto the Ni layer, the Ni content of the cladding metal being 11-18% of that in the cladding layer after casting. From the start of casting the Ni, the rotational speed of the mould is controlled to be 30-40% of its starting speed. The method allows tubes of length to-dia. ratio >8-10 to be cast in different steel types, and gives a base layer/cladding weld joint of improved notch ductility without post-treatment. This improvement is due to the presence of Ni which acts as a diffusion barrier for C.