MOCVD method and apparatus

A method for making a semiconductor device comprising the steps of:

• forming a substrate of a monocrystalline semiconductor compound selected from the group consisting of group III-V compounds and group II-VI compounds;
• heating the substrate;
• epitaxially growing a layer on a first surface of the substrate comprising the step of exposing the heated substrate to a gas comprising a metalorganic compound and a second compound;
• said metalorganic compound comprising an organic component and a metal selected from the group consisting of groups III and II of the periodic table;
• the second compound comprising an element selected from the group consisting of groups V and VI of the periodic table;
• said exposure causing a reaction of the metalorganic compound and the second compound which results in the epitaxial growth on a surface of the substrate of a semiconductor compound comprising a metal which originally constituted part of the metalorganic compound and an element which originally constituted part of the second compound, characterized by the steps of:
• providing an injection plate that is substantially parallel to the first surface of the substrate;
• the injection plate having first and second parallel surfaces and an outer periphery, the second surface facing the first surface of the substrate;
• providing in the injection plate at least one slot communicating with the first and second surfaces, the slot having a non-uniform width which is narrower at a region relatively near the center of the plate than at a region relatively near the periphery of the injection plate;
• rotating the substrate during deposition;
• and directing the gas to flow over the first surface of the injection plate in a substantially radially inward direction from a peripheral part of the injection plate toward the center of the injection plate, whereby at least part of the gas is transmitted through said slot before reaching the first surface of the substrate.