Patent ID: 7989021
Filing Date: 2011-08-02
Classification: C23C

Abstract:
1. A method of vaporizing particulate organic material at a uniform rate for forming an organic layer on a substrate, comprising: a) providing a chamber under low pressure conditions; b) providing a heating element within the chamber that produces heat; c) feeding at least one particulate organic material into the chamber to form an annular column of vaporizable material, wherein the cross-sectional area of the annular column is constant, but the volume of the annular column varies according to changes in the feed rate; d) providing a cold sink in operative relationship with the annular column to maintain the sides and bottom portion of the annular column at a controlled temperature below the effective vaporization temperature; and e) applying a constant current to the heating element so that a heat flux is delivered to the top surface of the annular column to vaporize the material to form the organic layer on the substrate, wherein the heating element has a low thermal mass so that a uniform volume per unit time of the material is vaporized when the feed rate of the annular column varies.