In-situ monitoring of MOCVD process
|關鍵字:||金屬有機化學氣相沈積;矽基氮化鎵;即時量測;反射率;曲率;metal organic chemical vapor deposition (MOCVD);GaN-on-silicon;in-situ measurement;reflectance;curvature|
Metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) are widely used in manufacture of GaN-on-silicon light emitting diodes (LED). Both epitaxial processes have to operate in sealed vacuum chambers. The quality and efficiency of LED lighting depend on wafer temperature, epitaxial compositions, thin film thickness, etc. This study develops on-line optical techniques to real-time measure manufacture situations during epitaxy. Reflectance from the epitaxial thin film is a function of its refractive index and the film thickness. The emissivity of a material equals subtraction of the reflectance from 1, and is used as a correction factor for the pyrometer. A history of reflectance during epitaxy shows surface roughness of wafer and growth rate of epitaxial film. Large curvature of the substrate in the GaN-on-silicon process usually results in dislocations and peeling off in epitaxial films. The wafer bow and residual stress based on the measured results was formulated to explore the influences caused by manufacture parameters. The in-situ measurement during MOCVD process will promote GaN-on-silicon technology through an efficient monitoring and following-up feedback and compensation for process control.
|Appears in Collections:||Thesis|