Heat dissipation component for semiconductor element

A heat dissipation component for a semiconductor element, the heat dissipation component comprising:

• a composite part containing 50-80 vol % diamond powder with the remainder being composed of metal including aluminum, the diamond powder being a diamond powder in which a first peak of a volume distribution of particle diameter is at 5-25 μm and in which a second peak is at 55-195 μm, wherein a ratio between an area of a volume distribution at particle diameters of 1-35 μm and an area of a volume distribution at particle diameters of 45-205 μm is 1:9 to 4:6;
• surface layers on both principal surfaces of the composite part, each of the surface layers containing 80 vol % or more metal including aluminum and having a film thickness of 0.03-0.2 mm;
• and
• a surface metal layer provided on at least one of the surface layers;
• wherein the surface metal layer consists of (1) a crystalline Ni plate layer and (2) an Au plate layer, the crystalline Ni plate layer has a film thickness of 0.5-6.5 μm, and the Au plate layer has a film thickness of 0.05 μm or larger.