Method of processing a target material
Methods of processing a target material are disclosed. In one arrangement, a multilayer structure is irradiated with a radiation beam. The multilayer structure comprises at least a target layer comprising the target material and an additional layer not comprising the target material. The additional layer is metallic. The target layer is irradiated through the additional layer during the irradiation of the multilayer structure. A transfer of energy from the radiation beam to the target layer and to the additional layer is such as to cause a thermally-induced change in the target layer. The thermally-induced change comprising one or more of: crystal growth in the target material, increased carrier mobility in the target material, increased chemical stability in the target material, and increased uniformity of electrical properties in the target material.
1. A method of processing a target material, comprising:
irradiating a multilayer structure with a radiation beam, the multilayer structure comprising at least a target layer comprising the target material and an additional layer not comprising the target material, wherein:
the additional layer is metallic;
the target layer is irradiated through the additional layer during the irradiation of the multilayer structure;
the radiation beam passes partially through the additional layer to the target layer during the irradiation of the multilayer structure, such that the radiation beam transfers energy to the target layer and the additional layer by depositing energy both in the target layer and in the additional layer; and
the transfer of energy from the radiation beam to the target layer and to the additional layer is such as to cause a thermally-induced change in the target layer, the thermally-induced change comprising crystal growth in the target material.
2. The method of claim 1 , wherein a fluence of the radiation beam is selected such that the thermally-induced change is achieved without any portion of the target layer entering a molten phase during the irradiation by the radiation beam.
3. The method of claim 1 , wherein a fluence of the radiation beam is selected such that at least a portion of the target layer enters a molten state during at least a portion of the irradiation by the radiation beam.
4. The method of claim 1 , wherein the additional layer has a thickness of less than 200 nm.
5. The method of claim 1 , wherein the irradiation of the multilayer structure causes detachment of at least an irradiated portion of the additional layer from the target layer after the thermally-induced change in the target layer has occurred.
6. The method of claim 1 , wherein the radiation beam is a pulsed laser beam.
7. The method of claim 6 , wherein a single pulse of the radiation beam causes crystal growth in the target material.
8. The method of claim 6 , wherein a pulse duration of the pulsed laser beam is less than 1 ns.
9. The method of claim 6 , wherein the pulsed laser beam comprises IR or visible radiation.
10. The method of claim 6 , wherein a plurality of pulses are applied to each region of the target material where crystal growth is to be promoted, wherein, in each said region, a first pulse of the plurality of pulses causes crystal growth and a later pulse of the plurality of pulses causes further crystal growth.
11. The method of claim 1 , wherein the target material comprises amorphous silicon.
12. The method of claim 1 , wherein the target material comprises a transparent conductive material.
13. The method of claim 1 , wherein the target material comprises indium gallium zinc oxide.
14. The method of claim 1 , wherein the target material comprises a dielectric material.
15. The method of claim 1 , wherein the target material comprises a metal or metal oxide.
16. The method of claim 1 , wherein the additional layer comprises molybdenum or tungsten.
17. The method of claim 1 , wherein the target material comprises amorphous silicon, the additional layer comprises molybdenum or tungsten and fluence provided by a single pulse of the radiation beam is in the range of 50-125 mJcm −2 .