Vaporizing Material at a Uniform Rate

Abstract

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.

1 - 13 . (canceled) 
     
     
         14 . An apparatus for providing uniform vaporization of a material comprising:
 a) a chamber;   b) a heating element within the chamber for providing vaporization energy;   c) a constant current source for providing a substantially constant heating flux to the heating element as vaporization energy thereby;   d) a feed apparatus for feeding a column of vaporizable material, at a substantially continuous rate, toward the heating element; and   e) a cold sink proximate the column of vaporizable material for dissipating heat absorbed by a portion of the column spaced apart form the heating element.   
     
     
         15 . The apparatus of  claim 14  wherein the heating, element is a flash vaporization heating element. 
     
     
         16 . The apparatus of  claim 14  wherein the heating element comprises a screen.