Abstract: A method of fabricating a composite semiconductor component comprising: (i) providing a bowed substrate comprising a wafer of synthetic diamond material having a thickness td, the bowed substrate being bowed by an amount B and comprising a convex face and a concave face; (ii) growing a layer of compound semiconductor material on the convex face of the bowed substrate via a chemical vapour deposition technique at a growth temperature T to form a bowed composite semiconductor component comprising the layer of compound semiconductor material of thickness tsc on the convex face of the bowed substrate, the compound semiconductor material having a higher average thermal expansion coefficient than the synthetic diamond material between the growth temperature T and room temperature providing a thermal expansion mismatch ?Tec; and (iii) cooling the bowed composite semiconductor component, wherein the layer of compound semiconductor material contracts more than the wafer of synthetic diamond material during cooling due

Abstract: A method of fabricating a composite semiconductor component comprising: (i) providing a bowed substrate comprising a wafer of synthetic diamond material having a thickness td, the bowed substrate being bowed by an amount B and comprising a convex face and a concave face; (ii) growing a layer of compound semiconductor material on the convex face of the bowed substrate via a chemical vapour deposition technique at a growth temperature T to form a bowed composite semiconductor component comprising the layer of compound semiconductor material of thickness tsc on the convex face of the bowed substrate, the compound semiconductor material having a higher average thermal expansion coefficient than the synthetic diamond material between the growth temperature T and room temperature providing a thermal expansion mismatch ?Tec; and (iii) cooling the bowed composite semiconductor component, wherein the layer of compound semiconductor material contracts more than the wafer of synthetic diamond material during cooling due

Abstract: A joint part (1) has a porous portion (2) that is defined by a multiplicity of solid regions where material is present and a remaining multiplicity of pore regions where material is absent, the locations of at least most of the multiplicity of solid regions being defined by one or more mathematical functions. The nature of the porous portion can be varied systematically by changing one or more constants in the mathematical functions and the part is made by a process of solid freeform fabrication.

Abstract: A method of manufacturing a composite substrate for a semiconductor device, the method comprising: selecting a substrate wafer comprising: a first layer of single crystal material suitable for epitaxial growth of a compound semiconductor thereon and having a thickness of 100 ?m or less;a second layer having a thickness of no less than 0.5 ?m and formed of a material having a lower thermal expansion coefficient than the first layer of single crystal material and/or is formed of a material which has a higher fracture strength than that of the first layer of single crystal material; and a third layer forming a handling wafer on which the first and second layers are disposed, wherein the substrate wafer has an aspect ratio, defined by a ratio of thickness to width, of no less than 0.

Abstract: A joint part (1) has a porous portion (2) that is defined by a multiplicity of solid regions where material is present and a remaining multiplicity of pore regions where material is absent, the locations of at least most of the multiplicity of solid regions being defined by one or more mathematical functions. The nature of the porous portion can be varied systematically by changing one or more constants in the mathematical functions and the part is made by a process of solid freeform fabrication.