Abstract: A semiconductor device includes a substrate, an insulating layer provided over the substrate, a collection of metal particles exposed on the surface of the insulating layer, and a diamond layer provided on the surface of the insulating layer on which the metal particles are exposed. By controlling the surface density and particle size of the metal particles on the surface of the insulating layer, the surface density of diamond nuclei that are formed on the surface is controlled. Diamond grains are formed by crystal growth using the diamond nuclei as starting material, thereby forming a diamond layer. The control of the surface density of the diamond nuclei results in forming, by the crystal growth, the diamond grains with a grain size exhibiting a relatively high thermal conductivity in the crystal growth initial layer of the diamond layer and improving the thermal conductivity between the diamond layer and the substrate.

Abstract: A semiconductor device includes an underlayer made of a first nitride semiconductor, a first buffer layer made of a second nitride semiconductor, provided on the underlayer, and subjected to compressive stress from the underlayer in an in-plane direction which is perpendicular to a thickness direction of the underlayer, a second buffer layer made of a third nitride semiconductor, provided on the first buffer layer, and subjected to compressive stress from the first buffer layer in the in-plane direction, a channel layer made of a fourth nitride semiconductor, provided on the second buffer layer, and subjected to compressive stress from the second buffer layer in the in-plane direction, and a barrier layer made of a fifth nitride semiconductor, and provided above the channel layer.

Abstract: A semiconductor device includes a source electrode and a drain electrode located over a surface of a semiconductor layer including an electron transit layer and an electron supply layer. A gate electrode is located between the source electrode and the drain electrode. A first diamond layer is located between the source electrode and the drain electrode over the surface with an insulating film therebetween. A second diamond layer is located directly on the surface between the gate electrode and the drain electrode. Of heat generated by the semiconductor layer of the semiconductor device in operation, heat on the side of the electrode on which a relatively strong electric field is applied is efficiently transferred to the second diamond layer. The semiconductor device achieves an excellent heat dissipation property from the semiconductor layer and effectively suppresses overheating and a failure and degradation of the characteristics due to the overheating.

Abstract: A semiconductor device includes a source electrode and a drain electrode located over a surface of a semiconductor layer including an electron transit layer and an electron supply layer. A gate electrode is located between the source electrode and the drain electrode. A first diamond layer is located between the source electrode and the drain electrode over the surface with an insulating film therebetween. A second diamond layer is located directly on the surface between the gate electrode and the drain electrode. Of heat generated by the semiconductor layer of the semiconductor device in operation, heat on the side of the electrode on which a relatively strong electric field is applied is efficiently transferred to the second diamond layer. The semiconductor device achieves an excellent heat dissipation property from the semiconductor layer and effectively suppresses overheating and a failure and degradation of the characteristics due to the overheating.

Abstract: A semiconductor device includes an underlayer made of a first nitride semiconductor, a first buffer layer made of a second nitride semiconductor, provided on the underlayer, and subjected to compressive stress from the underlayer in an in-plane direction which is perpendicular to a thickness direction of the underlayer, a second buffer layer made of a third nitride semiconductor, provided on the first buffer layer, and subjected to compressive stress from the first buffer layer in the in-plane direction, a channel layer made of a fourth nitride semiconductor, provided on the second buffer layer, and subjected to compressive stress from the second buffer layer in the in-plane direction, and a barrier layer made of a fifth nitride semiconductor, and provided above the channel layer.

Abstract: A semiconductor device includes a source electrode and a drain electrode located over a surface of a semiconductor layer including an electron transit layer and an electron supply layer. A gate electrode is located between the source electrode and the drain electrode. A first diamond layer is located between the source electrode and the drain electrode over the surface with an insulating film therebetween. A second diamond layer is located directly on the surface between the gate electrode and the drain electrode. Of heat generated by the semiconductor layer of the semiconductor device in operation, heat on the side of the electrode on which a relatively strong electric field is applied is efficiently transferred to the second diamond layer. The semiconductor device achieves an excellent heat dissipation property from the semiconductor layer and effectively suppresses overheating and a failure and degradation of the characteristics due to the overheating.

Abstract: A semiconductor device includes a substrate, an insulating layer provided over the substrate, a collection of metal particles exposed on the surface of the insulating layer, and a diamond layer provided on the surface of the insulating layer on which the metal particles are exposed. By controlling the surface density and particle size of the metal particles on the surface of the insulating layer, the surface density of diamond nuclei that are formed on the surface is controlled. Diamond grains are formed by crystal growth using the diamond nuclei as starting material, thereby forming a diamond layer. The control of the surface density of the diamond nuclei results in forming, by the crystal growth, the diamond grains with a grain size exhibiting a relatively high thermal conductivity in the crystal growth initial layer of the diamond layer and improving the thermal conductivity between the diamond layer and the substrate.