PLASMA ENHANCED THERMAL EVAPORATOR
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.