As for diamond heat sinks, the properties of Au eutectic alloys used for bonding a semiconductor chip to a diamond are investigated, and then, film-soldering method is studied in which a semiconductor chip is soldered to a metallized diamond substrate evenly under small load with low melting alloyed film.
As soldering materials, Au-Sb, Au-Sn and Au-In alloys are selected and their properties, viz. thermal conductivity, electric resistance, hardness and tensile strength, are investigated. In all alloys, their eutectic alloys have similar properties, and in Au-Sb alloy, which has no alloy phase in hypo-eutectic region, it can improve its properties when its composition becomes Au-rich from the eutectic composition.
In soldering experiments, Au-Sb alloy is mainly used and GaAs chips and Pyrex glass, as model specimens, are soldered in an atmosphere of H₂ gas. The effects of temperature, time, load, film thickness, film structure, and film composition on the soldering strength are investigated, resulting that the conditions for assuring the appropriate soldering are defined. From the XMA analysis of alloyed film's composition, together with above results, it is found that the rate of soldering reaction is controlled by the interdiffusion of Sb into Au solid phase.
In comparison with above results, similar investigation is carried out using Au-Sn alloy.

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The influence of electric field on the build-up process of tungsten field emitter was studied to explain the unexpected value of field correction energy ΔQ_F.
Some results as follows were found : (i) In case of relatively small tip radius r below 3000A ΔQ_F increases with the field F at same tip radius, while at larger radius above 3500A the available range of F for the measurement becomes narrower and then ΔQ_F nearly constant. (ii) At same F/F₀, ΔQ_F increased with the tip radius, where F₀ is the minimum filed to produce build-up and is inversely proportional to √r. It, therefore, must be noted that the apparent value of ΔQ_F may vary with F as well as F/F₀ considerably. (iii) Two build-up stages were observed in the build-up procedure. The initial build-up in the neighborhood of the {320} and {341} areas exhibits larger activation energy, and different field dependency from those of the complete build-up.

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