Method for producing semiconductive single crystal

Claim 1

A method for growing a ZnSe thin film on a ZnSe single crystal substrate, comprising the steps of: (a) placing a portion of a ZnSe polycrystal in a sealed reactor tube containing at least one gas selected form the group consisting of an inert gas, nitrogen and H 2 Se at a pressure of 0.1 Torr. to 100 Torr., (b) moving the reactor tube containing the ZnSe polycrystal through (i) a low temperature first zone maintained at a temperature from room temperature to 100° C., (ii) a temperature-raising second zone having a temperature gradient from 50° C./cm to 200° C./cm, (iii) a high temperature third zone maintained at a temperature from 700° C. to 900° C., wherein the temperature of the temperature raising second zone does not exceed the temperature of the high temperature third zone, (iv) a temperature-lowering fourth zone having a temperature gradient from -31 200° C./cm to -50° C./cm and (v) a low temperature fifth zone at a temperature from room temperature to 100° C. in this order at a rate of 0.05 mm/day to 5 mm/day while maintaining the solid state of the ZnSe crystal wherein ZnSe polycrystal is converted to ZnSe single crystal, (c) cutting the ZnSe single crystal to form a ZnSe single crystal substrate, (d) heating the ZnSe single crystal substrate in a hydrogen atmosphere under a pressure from 0.1 Torr. to 10 Torr. at a temperature from 250° C. to 450° C. while introducing a gaseous organozinc compound and H 2 Se gas in such amounts that a molar ration of Se/Zn is from 10 to 100 to grow the ZnSe thin film on the surface of the ZnSe single crystal substrate.

Claim 2

A method for growing a ZnSe thin film on a ZnSe single crystal substrate, comprising the steps of: (a) placing a portion of a ZnSe polycrystal in a sealed reactor tube containing at least one gas selected form the group consisting of an inert gas, nitrogen and H 2 Se at a pressure of 0.1 Torr. to 100 Torr., (b) moving the reactor tube containing the ZnSe polycrystal through (i) a low temperature first zone maintained at a temperature from room temperature to 100° C., (ii) a temperature-raising second zone having a temperature gradient from 50° C./cm to 200° C./cm, (iii) a high temperature third zone maintained at a temperature from 700° C. to 900° C., wherein the temperature of the temperature raising second zone does not exceed the temperature of the high temperature third zone, (iv) a temperature-lowering fourth zone having a temperature gradient from -31 200° C./cm to -50° C./cm and (v) a low temperature fifth zone at a temperature from room temperature to 100° C. in this order at a rate of 0.05 mm/day to 5 mm/day while maintaining the solid state of the ZnSe crystal wherein ZnSe polycrystal is converted to ZnSe single crystal, (c) cutting the ZnSe single crystal to form a ZnSe single crystal substrate, (d) heating the ZnSe single crystal substrate in a hydrogen atmosphere under a pressure from 0.1 Torr. to 10 Torr. at a temperature from 250° C. to 450° C. while introducing a gaseous organozinc compound and H 2 Se gas in such amounts that a molar ration of Se/Zn is from 10 to 100 to grow the ZnSe thin film on the surface of the ZnSe single crystal substrate.