Plasma enhanced thermal evaporator

Abstract

The present invention generally provides a method for forming a photovoltaic device including evaporating a source material to form a large molecule processing gas and flowing the large molecule processing gas through a gas distribution showerhead and into a processing area of a processing chamber having a substrate therein. The method includes generating a small molecule processing gas, and reacting the small molecule processing gas with a film already deposited on a substrate surface to form a semiconductor film. Additionally, apparatuses that may use the methods are also provided to enable continuous inline CIGS type solar cell formation.

1 . A method for forming a photovoltaic device, comprising:
 evaporating a source material to form a large molecule processing gas;   flowing the large molecule processing gas through a gas distribution showerhead and into a processing area of a processing chamber having a substrate therein;   igniting a plasma from the large molecule processing gas;   generating a small molecule processing gas with the plasma; and   reacting the small molecule processing gas with a film already deposited on a substrate surface to form a semiconductor film.   
     
     
         2 . The method of  claim 1 , wherein the source material comprises selenium. 
     
     
         3 . The method of  claim 2 , wherein the large molecule processing gas of selenium comprises selenium clusters having five or more selenium atoms. 
     
     
         4 . The method of  claim 2 , wherein the small molecule processing gas of selenium comprises selenium clusters having four or less selenium atoms. 
     
     
         5 . The method of  claim 4 , wherein the film already deposited on the substrate surface comprises copper, indium, and gallium. 
     
     
         6 . The method of  claim 5 , wherein the semiconductor film has a structure represented by the formula CuIn x Ga (1-x) Se 2  where 0≦x≦1. 
     
     
         7 . The method of  claim 1 , wherein the power level is 100 W/in 2  or less. 
     
     
         8 . A method for forming a photovoltaic device, comprising:
 evaporating a source material to form a large molecule processing gas;   flowing the large molecule processing gas through a gas distribution showerhead and into a processing area of a processing chamber having a substrate therein;   electrically biasing the showerhead to increase the energy level of the large molecule processing gas within the processing area without igniting a plasma in the processing area;   generating a small molecule processing gas by colliding processing gas molecules with each other; and   reacting the small molecule processing gas with a film already deposited on a substrate surface to form a semiconductor film.   
     
     
         9 . The method of  claim 8 , wherein the source material comprises selenium. 
     
     
         10 . The method of  claim 9 , wherein the large molecule processing gas of selenium comprises selenium clusters having five or more selenium atoms. 
     
     
         11 . The method of  claim 9 , wherein the small molecule processing gas of selenium comprises selenium clusters having four or less selenium atoms. 
     
     
         12 . The method of  claim 11 , wherein the film already deposited on the substrate surface comprises copper, indium, and gallium. 
     
     
         13 . The method of  claim 12 , wherein the semiconductor film has a structure represented by the formula CuIn x Ga (1-x) Se 2  where 0≦x≦1. 
     
     
         14 . The method of  claim 1 , wherein the power level is 100 W/in 2  or less. 
     
     
         15 . A method for forming a photovoltaic device, comprising:
 evaporating a source material to form a large molecule processing gas;   flowing the large molecule processing gas through a gas distribution showerhead and into a processing area of a processing chamber having a substrate therein;   igniting a plasma in a remote plasma source;   flowing ionized molecules from the remote plasma source, through a linear plasma showerhead, and into the processing area;   generating a small molecule processing gas with the ionized molecules; and   reacting the small molecule processing gas with a film already deposited on a substrate surface to form a semiconductor film.   
     
     
         16 . The method of  claim 15 , wherein the plasma is chosen group consisting of helium, argon, krypton, xenon, and radon. 
     
     
         17 . The method of  claim 15 , wherein the plasma is chosen from the group consisting of oxygen, nitrogen, and hydrogen. 
     
     
         18 . The method of  claim 15 , wherein the large molecule processing gas comprises selenium clusters having five or more selenium atoms. 
     
     
         19 . The method of  claim 15 , wherein the small molecule processing gas of selenium comprises selenium clusters having four or less selenium atoms. 
     
     
         20 . An apparatus for processing a substrate in a continuous inline photovoltaic device production process, the apparatus comprising:
 a processing chamber body;   a substrate positioner;   a linear gas distribution showerhead disposed in the processing chamber body, the linear gas distribution showerhead electrically coupled to a power source;   a gas conduit coupled to the showerhead; and   an evaporator coupled to the gas conduit.   
     
     
         21 . The apparatus of  claim 20 , wherein the linear gas distribution showerhead further comprises passages of varying cross-sectional perimeter. 
     
     
         22 . The apparatus of  claim 20 , wherein the linear gas distribution showerhead is arranged vertically within the chamber and the substrate positioner holds a substrate in a vertical processing position. 
     
     
         23 . An apparatus for processing a substrate in a continuous inline photovoltaic device production process, the apparatus comprising:
 a processing chamber body;   a substrate positioner;   a linear remote plasma distribution showerhead disposed in the processing chamber body;   a remote plasma source coupled to the linear remote plasma distribution showerhead, the remote plasma source is electrically coupled to a power source;   a linear gas distribution showerhead disposed in the processing chamber body;   a gas conduit coupled to the showerhead; and   an evaporator coupled to the gas conduit.   
     
     
         24 . The apparatus of  claim 23 , wherein the linear gas distribution showerhead further comprises passages of varying cross-sectional perimeter. 
     
     
         25 . The apparatus of  claim 23 , wherein the linear gas distribution showerhead is arranged vertically within the chamber and the substrate positioner holds a substrate in a vertical processing position.