Coaxial Hollow Cathode Plasma Assisted Directed Vapor Deposition and Related Method Thereof

Abstract

A plasma generation process that is more optimized for vapor deposition processes in general, and particularly for directed vapor deposition processing. The features of such an approach enables a robust and reliable coaxial plasma capability in which the plasma jet is coaxial with the vapor plume, rather than the orthogonal configuration creating the previous disadvantages. In this way, the previous deformation of the vapor gas jet by the work gas stream of the hollow cathode pipe can be avoided and the carrier gas consumption needed for shaping the vapor plume can be significantly decreased.

1 - 37 . (canceled) 
     
     
         38 . A method for depositing at least one evaporant onto at least one substrate, said method comprising:
 providing at least one substrate,   providing at least one evaporant source,   impinging said at least one evaporant source with an energetic beam to generate a vapor plume,   generating a plasma and discharging a current that is aligned with said vapor plume,   emitting at least one plasma forming gas in a direction that is at least substantially aligned with said vapor plume,   electrostatically attracting said discharge current towards at least one anode, and   interacting said plasma with said substrate.   
     
     
         39 . The method of  claim 38 , wherein said discharge current is emitted by at least one hollow cathode operating in a high-current, low-voltage arc mode, forming a low-voltage electron beam. 
     
     
         40 . The method of  claim 38 , wherein said at least one evaporant source is a solid. 
     
     
         41 . The method of  claim 38 , wherein said discharge current is changed to modulate or control the plasma density. 
     
     
         42 . The method of  claim 39 , wherein said at least one hollow cathode emits said plasma-forming gas such as to generate a plasma jet streaming off of the hollow cathode's orifice. 
     
     
         43 . The method of  claim 42 , wherein the axis and/or momentum of said plasma jet and of said low-voltage electron beam is at least substantially aligned with that of the said hollow cathode. 
     
     
         44 . The method of  claim 42 , wherein said plasma jet at least partially entrains said vapor plume and at least partially assists in transporting said vapor plume to said substrate. 
     
     
         45 . The method of  claim 42 , wherein said plasma jet at least partially shapes said vapor plume. 
     
     
         46 . The method of  claim 44 , wherein at least some of the vapor plume is ionized by said plasma jet and by said low-voltage electron beam. 
     
     
         47 . The method of  claim 38 , further comprising providing a heat source for initiating said plasma emission. 
     
     
         48 . The method of  claim 47 , wherein said heat source comprises a heat source based on Ohmic heating of a current conductor, a heat source based on an auxiliary gas discharge, or a kicker circuit to ignite the hollow cathode emission via a high-voltage impulse. 
     
     
         49 . The method of  claim 38 , further comprising providing at least one cooling device for cooling said at least one evaporant source. 
     
     
         50 . The method of  claim 49 , wherein said cooling source comprises a crucible. 
     
     
         51 . The method of  claim 44 , wherein said at least one of said hollow cathodes are realized in an annular configuration comprising two coaxial cylinders of slightly different diameters thus forming an annular slot which facilitates the hollow cathode effect. 
     
     
         52 . The method of  claim 44 , wherein said two or more hollow cathodes are positioned in an annular configuration around said at least one evaporant source with the evaporant source at least substantially coaxially integrated inside said annular configuration. 
     
     
         53 . The method of  claim 52 , wherein relative intensity of the plasma jets generated by said at least one hollow cathodes may be controlled for directional sweeping either of said plasma or vapor plume, or both, from side to side. 
     
     
         54 . The method of  claim 53 , wherein said directional sweeping is accomplished by controlling the pressure or gas flow rate individually in each hollow cathode. 
     
     
         55 . The method of  claim 53 , wherein said directional sweeping is accomplished by controlling the direction of emission. 
     
     
         56 . The method of  claim 38 , wherein said energetic beam is produced by an electron beam gun, or laser. 
     
     
         57 . The method of  claim 56 , wherein said energetic beam source further comprises means to alter the beam impingement points among said one or more evaporant sources. 
     
     
         58 . The method of  claim 38 , further comprising providing a bias voltage applied to said substrate for accelerating ions toward said substrate. 
     
     
         59 . The method of  claim 58 , wherein said bias voltage is a DC, AC, or pulsed voltage. 
     
     
         60 . The method of  claim 42 , further comprising means for the inlet of at least one secondary gas forming at least one jet positioned at least substantially coaxially with said at lets one evaporant source and said at least one hollow cathode. 
     
     
         61 . The method of  claim 60 , wherein said at least one secondary gas at least partially assist in shaping and transporting said vapor plume to said substrate. 
     
     
         62 . The method of  claim 60 , wherein said secondary gas jets introduce reactant gases for creating compounds with the vapor plume. 
     
     
         63 . The method of  claim 38 , wherein said hollow cathode discharges current to an annular anode. 
     
     
         64 . The method of  claim 63 , wherein said anode is configured in an elevated position above said hollow cathode source. 
     
     
         65 . The method of  claim 38 , further comprising positioning said anode above said substrate. 
     
     
         66 . The method of  claim 38 , further comprising positioning said anode between said substrate and said hollow cathode. 
     
     
         67 . The method of  claim 38 , wherein said anode further comprises means for creating a magnetic field and for guiding a magnetic flux such that the magnetic field lines in front of the annular anode are substantially parallel to its surface and radially directed thus forming a closed electrons drift track in circumferential direction which is substantially parallel to the anode's surface. 
     
     
         68 . The method of  claim 67 , wherein said magnetic field arrangement facilitates an axial potential gradient for accelerating positive ions toward said substrate. 
     
     
         69 . The method of  claim 38 , further comprising positioning said anode at least substantially coaxially and in the same plane as the at least one hollow cathode. 
     
     
         70 . The method of  claim 69 , further comprising bisecting said anode radially to form anode segments. 
     
     
         71 . The method of  claim 70 , further comprising bisecting said anode into the same number of segments as the number of hollow cathodes and the hollow cathode emissions burn diametrically across the vapor plume between each one of the at least one hollow cathodes and corresponding anode segment situated at the opposite position. 
     
     
         72 . The method of  claim 38 , further comprising positioning a solenoid at least partially proximal to said hollow cathode. 
     
     
         73 . The method of  claim 72 , wherein said solenoid is capable of at least partially bending said energetic beam. 
     
     
         74 . The method of  claim 72 , wherein said solenoid is positioned an energized such as to magnetically enhance the at least one hollow cathode's efficiency. 
     
     
         75 . The method of  claim 72 , wherein said solenoid at least partially increases plasma density and facilitates an axial potential gradient for accelerating positive ions toward said substrate. 
     
     
         76 - 77 . (canceled) 
     
     
         78 . The method of  claim 38 , wherein said alignment of said discharging current with said vapor plume is at least substantially coaxial. 
     
     
         79 . The method of  claim 38 , wherein said substantial alignment of the emission direction of said plasma forming gas with said vapor plume is at least substantially coaxial. 
     
     
         80 . The method of  claim 44 , wherein said at least one hollow cathodes comprises at least one of the following: pipe, conduit, tube, channel, hose, stem, duct, port, groove, passage, tunnel, and port. 
     
     
         81 . The method of  claim 52 , wherein said annular configuration provides an array. 
     
     
         82 . The method of  claim 57 , wherein said altering means comprises at least one deflection coil.