PURPOSE: To manufacture a quantum fine wire of high carrier mobility which can control the wire width accurately at atomic level.

CONSTITUTION: A quantum well 2 is formed by alternating semiconductor layers of high lattice constant and semiconductor layers of smaller lattice constant A, B and etched obliquely in the top face to expose a slope cross section, and two kinds of semiconductor layers C, G different in band gap with lattice constant smaller than that of the semiconductor layer A of high lattice constant are grown on the slope cross section. These semiconductor layers C, G undergo different stresses by the semiconductor layers A, B and deform the band structure. A part of the semiconductor layer G which has a small band gap turns into a quantum fine wire D in an extension of the semiconductor layer A which has an over lattice constant.