Patent ID: 7518151

Claim:
A gallium nitride/sapphire thin film, wherein a curvature radius thereof is positioned on the right side of a curve plotted from the following functional formula (I): Y=Y 0 +A·e −(x 1 −1)/T 1 +B ·(1 −e −x 2 /T 2 ) (I) wherein Y is the curvature radius (m) of a gallium nitride/sapphire thin film, x 1 is the thickness (μm) of a gallium nitride layer, x 2 is the thickness (mm) of a sapphire substrate, Y 0 is −107±2.5, A is 24.13±0.50, B is 141±4.5, T 1 is 0.56±0.04, and T 2 is 0.265±0.5.