| 摘要 |
PROBLEM TO BE SOLVED: To provide a GaN-based semiconductor free-standing substrate for a high quality substrate that may achieve sufficient electronic device properties.SOLUTION: A free-standing substrate consists of GaN, in which an RMS value in the area of 1×1 μmmeasured in the region other than 1 mm periphery of the surface using an AFM(Atomic Force Microscopy) is 1 nm or less, and a peak intensity ratio of the ion mass spectrum of SiO/Ga of the surface measured by TOF-SIMS, in which primary ion is Au, primary ion acceleration voltage is 25kV, scan area is 200 μm square, and secondary ion integration time is 150 seconds is 0.1 or less. The surface of the free-standing substrate is polished with colloidal silica as a polishing particle and its dislocation density is 1×10cmor less. |
