PURPOSE: To obtain a P-type II-VI compound semiconductor thin-film crystal being excellent in crystallizability and having a high carrier concentration first by irradiating a substrate with a group II element and trace group V impurity element so that they are combined with each other, and thereafter by irradiating the substrate with a group VI element.

CONSTITUTION: A group II element Zn and group VI element Se are selected as the constituting elements of a III-VI compound semiconductor thin-film crystal and a group V element N, as P-type impurity element. Zn and Se are contained in the molecular beam sources 5a and 5b of a molecular beam crystal-growing apparatus 10, respectively. When these molecular beam sources 5a, 5b are heated by a heater, vapor is generated and radiated as molecular beam. Also, a gas cylinder 8 filled with gaseous nitrogen N2 is connected with a radical beam source 7. When the gaseous nitrogen N2 is excited by high frequency, etc., the molecular beam is radiated as radical beam. A ZnSe thin-film crystal layer is formed on a semi-insulating GaAs substrate 4 raised in temperature by the irradiation of the molecular beam and radical beam.