Systems and methods for laser splitting and device layer transfer
Methods and systems are provided for the split and separation of a layer of desired thickness of crystalline semiconductor material containing optical, photovoltaic, electronic, micro-electro-mechanical system (MEMS), or optoelectronic devices, from a thicker donor wafer using laser irradiation.
1. A method for splitting and separating a layer of desired thickness of crystalline semiconductor material containing optical, photovoltaic, electronic, microelectro-mechanical system (MEMS), or optoelectronic devices from a donor wafer; comprising:
using laser irradiation on the same side which contains said devices, said laser irradiation using a focused laser beam scanned across said donor wafer and forming a two-dimensional separation layer of micro-crack spots; and
using a liquid nitrogen spray to facilitate releasing said crystalline semiconductor material along said separation layer.
2. The method of claim 1 , wherein said crystalline semiconductor material is silicon.
3. The method of claim 2 , wherein said crystalline silicon is monocrystalline silicon.
4. The method of claim 3 , wherein said two-dimensional separation layer of micro-crack spots is formed in the (111) crystallographic plane of said monocrystalline silicon.
5. The method of claim 1 , further comprising the steps of:
forming a splitting layer having a higher laser irradiation absorption selectivity as compared to said crystalline semiconductor material in said donor wafer, said splitting layer formed under said devices.
6. The method of claim 5 , wherein said splitting layer has a higher doping as compared to said crystalline semiconductor material.
7. The method of claim 1 , further comprising the step of attaching a support handler to said device side of said donor wafer prior to said release of said crystalline semiconductor material.
8. The method of claim 1 , wherein said devices are photovoltaic devices.