Reacted particle deposition (RPD) method for forming a compound semi-conductor thin-film
A method is provided for fabricating a thin-film semiconductor device. The method includes providing a plurality of raw semiconductor materials. The raw semiconductor materials undergo a pre-reacting process to form a homogeneous compound semiconductor material. This pre-reaction typically includes processing above the liquidus temperature of the compound semiconductor. The compound semiconductor material is reduced to a particulate form and deposited onto a substrate to form a thin-film having a composition and atomic structure substantially the same as a composition and atomic structure of the compound semiconductor material.
1. A method of fabricating a thin-film semiconductor device, comprising:
providing a homogeneous compound semiconductor material having a uniform composition and a uniform molecular structure and bonding;
forming fine-compound semiconductor particles less than 1 micrometer in dimension from the homogeneous compound semiconductor material;
depositing the fine compound semiconductor particles, or a dispersion thereof, onto a substrate to form a deposited thin-film; and
thermally processing the deposited thin-film to form a thermally processed thin-film having a composition substantially the same as a composition of the homogeneous compound semiconductor material.
2. The method of claim 1 wherein the homogeneous compound semiconductor material include II-VI compound semiconductor materials.
3. The method of claim 2 wherein the II-VI compound semiconductor materials are selected from the group consisting of Cd—S, Cd—Se, Cd—Te, Cd—Zn—Te, Cd—Hg—Te, Cu—In—Se.
4. The method of claim 3 further comprising providing Cu as a minor constituent along with the II-VI compound semiconductor materials.
5. The method of claim 1 wherein the homogeneous compound semiconductor material include compound semiconductor materials.
6. The method of claim 5 wherein the compound semiconductor materials are selected from the group consisting of Cu—In—Se, Cu—In—Ga—Se, Cu—In—Ga—Se—S.
7. The method of claim 6 further comprising providing Al in complete or partial substitution for Ga.
8. The method of claim 5 further comprising providing Na as a minor constituent along with the compound semiconductor materials.
9. The method of claim 5 further comprising providing an alkali element other than Na as a minor constituent long with the compound semiconductor materials.
10. The method of claim 5 further comprising providing F as a minor constituent along with the compound semiconductor materials.
11. The method of claim 5 further comprising providing a halogen element other than F as a minor constituent along with the compound semiconductor materials.
12. The method of claim 1 wherein the dispersion of the fine-compound semiconductor particles is formed in a carrier material selected from the group consisting of alcohols, polyols, acids, hydrocarbons, and water.
13. The method of claim 1 wherein a concentration of the fine-compound semiconductor particles in the dispersion is between about 5% weight concentration and 50% weight concentration.
14. The method of claim 1 further comprising pre-reacting a plurality of raw semiconductor materials to form the homogeneous compound semiconductor material having the uniform composition and the uniform molecular structure and bonding.
15. The method of claim 14 wherein said pre-reacting the plurality of raw semiconductor materials includes processing the plurality of raw semiconductor materials in a sealed pressurized vessel in an atmosphere of inert gas.
16. The method of claim 15 wherein said processing the plurality of raw semiconductor materials further comprising heating the sealed pressurized vessel.
17. The method of claim 16 wherein said heating the sealed pressurized vessel includes heating the sealed pressurized vessel to a temperature above the liquidus temperature of the plurality of raw semiconductor materials.