An electronic device includes a substrate; a single-crystalline first buffer layer, disposed on the substrate, containing a semiconductor represented by the formula Al.sub.xGa.sub.1-xN; a non-single-crystalline second buffer layer, disposed on the first buffer layer, containing a semiconductor represented by the formula Al.sub.yGa.sub.1-yN; and an undoped base layer, disposed on the second buffer layer, containing GaN, wherein 0<.times..ltoreq.1 and 0.ltoreq.y.ltoreq.1. The first buffer layer is formed at a temperature of 1000.degree. C. to 1200.degree. C. The second buffer layer is formed at a temperature of 350.degree. C. to 800.degree. C. The substrate contains SiC. The second buffer layer has a thickness of 5 to 20 nm.