A method for forming a trench diode for a power semiconductor device includes forming a first trench having a first opening and a second trench having a second opening in a substrate material, the second opening of the second trench being wider than the first opening of the first trench. An insulating layer is formed over surfaces of the first and second trenches. A first semiconductor material is provided within the first and second trenches, the first semiconductor material filling the first trench at least until the first opening is entirely plugged and partially filling the second trench so that a portion of the second opening remains open, the first semiconductor material having a first conductivity type. A second semiconductor material is provided within the second trench and over the first semiconductor material, the second semiconductor material having a second conductivity type that is different from the first conductivity type.