| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To eliminate a defect in a surface layer part of a crystal material such as a thick silicon wafer having a large thermal capacity thereby to enable an efficient improvement of the quality of the crystal material. <P>SOLUTION: A crystal material quality improving method includes the step of assist-heating the crystal material surface by a continuous laser light while scanning the crystal material surface by a pulse laser, whereby the crystal material surface ends up undergoing the repetition of laser irradiation repeatedly. A surface layer part of the crystal material where an irradiated area 25a subjected to the assist heating agrees with or overlaps an irradiated area 15a subjected to the pulse laser light irradiation experiences complex irradiation, the crystal material is completely melted there. Thus, a solid-state portion of the crystal material serves as a seed crystal there, and the crystal material goes into a liquid crystal epitaxial growth, whereby the crystal material surface layer part is improved in quality. The crystal material can be completely melted to a depth of a few micrometers to form a crystal defect-free device layer. As the temperature rise of the whole crystal material can be suppressed, the thermal stress at the time of cooling can be relaxed. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
