Real time process monitoring and control for semiconductor junctions
View Patent ↗A method of manufacturing a semiconductor layer is provided. In a first deposition during a first period of time, at least one Group IIIA element and at least one Group VIA element are deposited on a substrate or on a layer optional disposed on the substrate such as a back-electrode. During a second deposition during a second period of time, at least one Group IB element and the at least one group VIA element are deposited on the substrate or the optional layer. The one Group IB element combines with the Group VIA element to form a IB 2 VIA composition. A first deposition state is monitored, during the second deposition by making a first plurality of measurements of a first deposition state. The second deposition is terminated or attenuated based on a function of the first plurality of measurements of the indicia of the first deposition state.
1. A method of manufacturing a semiconductor layer comprising:
i) depositing, during a first period of time, at least one Group IIIA element and at least one Group VIA element on a substrate or on an optional layer that is optionally disposed on the substrate;
ii) depositing, during a second period of time, at least one Group IB element and said at least one group VIA element on the substrate or on the optional layer that is optionally disposed on the substrate, wherein at least a portion of said at least one Group IB element combines with said at least one Group VIA element to form a IB 2 VIA composition;
iii) monitoring a first deposition state, during said depositing step ii), by making a first plurality of measurements of an indicia of said first deposition state; and
iv) terminating or attenuating said depositing step ii) at a first critical control point based on a function of said first plurality of measurements of said indicia of said first deposition state.
2. The method of claim 1 , the method further comprising:
v) depositing, during a third period of time, at least one additional Group IIIA element and said at least one Group VIA element;
vi) monitoring a second deposition state, during said depositing step v), by making a second plurality of measurements of an indicia of said second deposition state; and
vii) terminating or attenuating said depositing step v) at a second critical control point based on a function of said second plurality of measurements of said indicia of said second deposition state.
3. The method of claim 1 , wherein said at least one Group IIIA element comprises Gallium (Ga), Indium (In), Aluminum (Al), or Thallium (Tl).
4. The method of claim 1 , wherein said at least one Group VIA element comprises Sulfur (S), Selenium (Se), Tellurium (Te), or Polonium (Po).
5. The method of claim 1 , wherein said at least one Group IB element comprises Copper (Cu), Silver (Ag), or Gold (Au).
6. The method of claim 1 , wherein said semiconductor layer comprises CuIn 1-x Ga x Se 2 , 0≦x≦1.
7. The method of claim 1 , wherein said semiconductor layer comprises CuIn 1-x Ga x (Se y S 1-y ) 2 , wherein 0≦x, y≦1.
8. The method of claim 1 , wherein said substrate is cylindrical.
9. The method of claim 1 , wherein said substrate is planar.
10. The method of claim 1 , wherein said first period of time is between 15 minutes and 60 minutes.
11. The method of claim 1 , wherein said second period of time is between 15 minutes and 60 minutes.
12. The method of claim 2 , wherein said third period of time is between 15 minutes and 60 minutes.
13. The method of claim 1 , wherein there is a time gap between said depositing step i) and depositing step ii).
14. The method of claim 13 , wherein a precursor is formed on said substrate or said optional layer on said substrate during at least a portion of said time gap.
15. The method of claim 13 , wherein a precursor is formed by said at least one Group IIIA element and said at least one Group VIA element during at least a portion of said time gap.
16. The method of claim 1 , wherein said function of said first plurality of measurements of said indicia of said first deposition state is a second order derivative, with respect to time, of said first plurality of measurements.
17. The method of claim 16 , wherein said first critical control point occurs when said second order derivative, with respect to time, approaches a threshold value.
18. The method of claim 17 , wherein said threshold value is zero.
19. The method of claim 2 , wherein said function of said second plurality of measurements of said indicia of said second deposition state is a second order derivative, with respect to time, of said second plurality of measurements.
20. The method of claim 19 , wherein said second critical control point occurs when said second order derivative, with respect to time, approaches a threshold value.
21. The method of claim 20 , wherein said threshold value is zero.
22. The method of claim 1 , wherein said IB 2 VIA composition is Cu 2 Se.
23. The method of claim 1 , wherein said indicia of said first deposition state is a temperature of said substrate or said optional layer on said substrate, a refractive index of said substrate or said optional layer on said substrate, or a vapor pressure.
24. The method of claim 2 , wherein said indicia of said second deposition state is a temperature of said substrate or said optional layer on said substrate, a refractive index of said substrate or said optional layer on said substrate, or a vapor pressure.
25. The method of claim 2 , wherein said indicia of said first deposition state and said indicia of said second deposition state are the same.
26. The method of claim 2 , wherein said indicia of said first deposition state and said indicia of said second deposition state are different.
27. The method of claim 1 , wherein said function of said first plurality of measurements of said indicia of said first deposition state is a first order derivative, with respect to time, of said first plurality of measurements of said indicia of said first deposition state.
28. The method of claim 27 , wherein said first critical control point occurs when said first order derivative, with respect to time, falls below a threshold value.
29. The method of claim 28 , wherein the first order derivative, with respect to time, falls below said threshold value when said first order derivative achieves a minimum value.
30. The method of claim 27 , wherein said first critical control point occurs when said first order derivative, with respect to time, rises above a threshold value.
31. The method of claim 30 , wherein the first order derivative, with respect to time, rises above said threshold value when said first order derivative achieves a maximum value.
32. The method of claim 2 , wherein said function of said second plurality of measurements of said indicia of said second deposition state is a first order derivative, with respect to time, of said second plurality of measurements of said indicia of said second deposition state.
33. The method of claim 32 , wherein said second critical control point occurs when said first order derivative, with respect to time, falls below a threshold value.
34. The method of claim 33 , wherein the first order derivative, with respect to time, falls below said threshold value when said first order derivative achieves a minimum value.
35. The method of claim 32 , wherein said second critical control point occurs when said first order derivative, with respect to time, rises above a threshold value.
36. The method of claim 35 , wherein the first order derivative, with respect to time, rises above said threshold value when said first order derivative, with respect to time, achieves a maximum value.
37. The method of claim 1 , wherein said at least one Group IIIA element and said at least one Group VIA element form a precursor IIIA 2 VIA 3 composition on said substrate or said optional layer on said substrate.
38. The method of claim 37 , wherein said precursor IIIA 2 VIA 3 composition is (In x Ga 1-x ) 2 (Se y S 1-y ) 3 , wherein 0≦x, and y≦1.
39. The method of claim 37 , wherein said precursor IIIA 2 VIA 3 composition is (In x Ga 1-x ) 2 Se 3 , wherein 0≦x≦1.
40. The method of claim 1 , wherein the optional layer is disposed on the substrate.
41. The method of claim 40 , wherein the optional layer is a back-electrode.
42. The method of claim 1 , wherein the optional layer is not disposed on the substrate and the i) depositing step i) deposits at least one Group IIIA element and at least one Group VIA element on the substrate.