PURPOSE: To restrain aluminum migration and thus obtain a Schottky junction which makes low-resistant the connection among a gate electrode, memory, and a wiring by a method wherein a device is composed by successively laminating an aluminum layer, layer of a metal except aluminum, and an aluminum layer on a compound semiconductor layer.

CONSTITUTION: The gate electrode is formed by successively laminating the Al layer 21, the hetero metal 22 such as Ti or Ni, and the Al layer 23 on a GaAs substrate 1. The Al layer 21 forms a Schottky junction between the GaAs substrate 1. Next, a Ti layer 24, a Pt layer 25, and an Au layer 26 are successively laminated as the wiring to connect the gate electrode to a bonding pad. Since the surface of the hetero metallic layer 22 is thus covered with the Al layer 23, an insulator layer is not formed, and the Al layer 23 is joined to the Ti layer in low resistance. The migration of the Al layers 21 and 23 is restrained because of providing the hetero metallic layer 22 and the Ti layer 24, resulting in no generation of problems such as disconnection.