Abstract: A heterojunction bipolar transistor includes a substrate, a semiconductor unit, an electrode unit and a dielectric layer. The semiconductor unit includes a collector layer, a base layer and an emitter layer sequentially formed on the substrate in such order. The electrode unit includes a collector electrode, a base electrode, and an emitter electrode respectively disposed on the collector layer, the base layer and the emitter layer. The dielectric layer covers and cooperates with the emitter layer to define an opening extending therethrough and terminating at the base layer to expose a contact region. The base electrode is disposed on the contact region, extends through the opening, and partially covers the dielectric layer.

Abstract: A semiconductor device includes a substrate, at least one heterojunction bipolar transistor including a semiconductor unit and an electrode unit, an insulation unit, and a heat dissipation unit. The insulation unit covers the substrate and the heterojunction bipolar transistor such that a collector electrode, a base electrode and an emitter electrode of the electrode unit are electrically isolated from one another. The insulation unit is formed with an opening to expose an electrode wire of the emitter electrode. The heat dissipation unit covers the electrode wire and is made of an electrically conductive and heat dissipating material, and has a thickness that is not less than 3 ?m.

Abstract: A heterojunction bipolar transistor includes a substrate, a semiconductor unit, an electrode unit and a dielectric layer. The semiconductor unit includes a collector layer, a base layer and an emitter layer sequentially formed on the substrate in such order. The electrode unit includes a collector electrode, a base electrode, and an emitter electrode respectively disposed on the collector layer, the base layer and the emitter layer. The dielectric layer covers and cooperates with the emitter layer to define an opening extending therethrough and terminating at the base layer to expose a contact region. The base electrode is disposed on the contact region, extends through the opening, and partially covers the dielectric layer.