Vaporizing material at a uniform rate

摘要

A method of vaporizing material at a uniform rate for forming a layer on a substrate includes feeding a column of vaporizable material from a temperature controlled region maintained below the vaporizable material's effective vaporization temperature to a source of vaporization energy, wherein the volume of the column can vary during vaporization; and providing a source of vaporization energy delivering a constant heat flux to the surface of the column so that a uniform volume per unit time of the vaporizable material is vaporized to form the layer on the substrate, irrespective of the feeding rate.