Controlling the stoichiometry and doping of semiconductor materials
Methods for treating a semiconductor material are provided. According to an aspect of the invention, the method includes annealing the semiconductor material in the presence of a compound that includes a first element and a second element. The first element provides an overpressure to achieve a desired stoichiometry of the semiconductor material, and the second element provides a dopant to the semiconductor material.
1. A method of treating a semiconductor material, the method comprising:
annealing the semiconductor material in the presence of a compound that includes a first element and a second element; wherein:
the first element provides a vapor overpressure to achieve a desired stoichiometry of the semiconductor material, wherein the stoichiometry is a ratio of components of the semiconductor material, and
the second element provides a dopant to the semiconductor material.
2. The method according to claim 1 , wherein a vapor pressure of the semiconductor material is lower than a vapor pressure of the compound.
3. The method according to claim 1 , wherein a vapor pressure of the first element is lower than a vapor pressure of the second element.
4. The method according to claim 1 , wherein the semiconductor material is CdTe or an alloy of CdTe, the first element is Cd, and the stoichiometry is Cd-rich.
5. The method according to claim 4 , wherein the second element is selected from Column VA of the periodic table.
6. The method according to claim 4 , wherein the second element is P, As, or Sb.
7. The method according to claim 4 , wherein the second element is P.
8. The method according to claim 4 , wherein the compound is Cd 3 P 2 .
9. The method according to claim 1 , wherein the semiconductor material is CdTe or an alloy of CdTe, the first element is Te, and the stoichiometry is Te-rich.
10. The method according to claim 9 , wherein the second element is selected from Column IB of the periodic table.
11. The method according to claim 9 , wherein the second element is Cu, Ag, or Au.
12. The method according to claim 1 , wherein the semiconductor material is CdTe or an alloy of CdTe, and the annealing is performed at a temperature greater than approximately 600° C.
13. The method according to claim 1 , wherein the semiconductor material is CdTe or an alloy of CdTe, and the annealing is performed at a temperature greater than approximately 700° C.
14. The method according to claim 1 , further comprising subsequently annealing the treated semiconductor material in the presence of the first element.
15. The method according to claim 14 , wherein the first element is Cd.
16. The method according to claim 14 , wherein the subsequent annealing is performed at a first temperature between approximately 300° C. and approximately 600° C.
17. The method according to claim 16 , further comprising heating the treated and subsequently annealed semiconductor material at a second temperature that is lower than the first temperature, and in the presence of ambient materials that promote at least one of annihilation or re-evaporation of excess quantities of the first element from the semiconductor material.