SEMICONDUCTOR ELEMENT, ELECTRIC APPARATUS, BIDIRECTIONAL FIELD EFFECT TRANSISTOR, AND MOUNTING STRUCTURAL BODY

摘要

Provided is a small-loss semiconductor element using polarization super junction, said semiconductor element being capable of easily breaking a tradeoff relationship between withstand voltage increase and speed increase, eliminating current collapse, while increasing a withstand voltage, and being capable of performing high-speed operations. This semiconductor element has a polarization super-junction region, and a p electrode contact region. The polarization super-junction region has: an undoped GaN layer (11); an undoped AlxGa1-xN layer (12) having a thickness of 25-47 nm, 0.17≤x≤0.35; an undoped GaN layer (13); and a p-type GaN layer (14). When conversion thickness (tR) is defined as tR=u+v(1+w×10-18), where, a thickness of the undoped GaN layer (13) is represented by u [nm], a thickness of the p-type GaN layer (14) is represented by v [nm], and Mg concentration is represented by w [cm-3], the following formula is satisfied: tR≥0.864/(x-0.134)+46.0 [nm]. The p electrode contact region has: a p-type GaN contact layer that is provided in contact with the p-type GaN layer (14); and a p electrode in ohmic contact with the p-type GaN contact layer.