A transistor having an electron quantum-wave interference layer with plural periods of a pair of a first layer W and a second layer B in a p-layer of a pn junction structure. The second layer B has wider band gap than the first layer W. Each thicknesses of the first layer W and the second layer B is determined by multiplying by an odd number one fourth of quantum-wave wavelength of carriers in each of the first layer W and the second layer B, the carriers existing around the lowest energy level of the second layer B. The quantum-wave interference layer functions as an electron reflecting layer, and enables to lower a dynamic resistance of the transistor notably. An amplification factor of a bipolar transistor of an npn junction structure, having the electron reflecting layer is improved compared with a transistor without an electrode reflecting layer. Similarly, a transistor having a hole reflecting layer, which has a larger amplification factor, can be obtained. Forming a hole reflecting layer can be applied to a field effect transistor such as a MESFET.