| Summary: | 碩士 === 中興大學 === 精密工程學系所 === 102 === The main goal of this research is to develop in-situ monitoring technology of GaN-based materials grown by metalorganic chemical vapor deposition (MOCVD) for epilayer stress measurement. Using this technique,
we can understand the stress variation between the wafer and epitaxial film while temperature decreases from growing temperature to room temperature.
Because the different thermal expansion coefficient between the GaN epilayer and substrate, it will lead to wafer bending, cracking and reducing the yield rate of devices. New nondestructive measurement technique using simple optical system and LabVIEW program have been constructed. A new concept to establish the triangular relationships among the incident a collimated laser
beam to wafer and a collected reflected laser spot position sensitive detector(PSD).The results are discussed in two directions: First, in-situ monitoring system was used to measure the curvature variation of GaN on sapphire during the epilayer growth. It will be compared with that of GaN grown on sapphire by Aixtron 200/4RF-S MOCVD system with Epi-curve-TT. The results indicate the measured curve by homemade system presents the same tendency measured by Epi-curve-TT. Second, comparison the epilayer curvature measured by in-situ monitoring system and ROC Tencor FLX-2320,the error of R in % is about 7.018. As mentioned above, the present research has successfully developed an in-situ curve measured system for GaN MOCVD epitaxial equipment in real-time monitoring system.
|
|---|
