Investigation of dopant dependent wave velocity in GaN thin film SAW filter

Undoped, Zn-doped, Mg-doped GaN thin film were prepared on sapphire substrate by MOCVD. SAW velocity was measured with the center frequency by HP8753C. Mg-doped GaN has the highest SAW velocity of 5617 m/s at kh=0.157 and undoped GaN has the lowest SAW velocity of 5400 m/s at kh=0.188. TCF is -60.8 ppm//spl deg/C for undoped GaN, -46.8 ppm//spl deg/C for Zn-doped GaN and -18.3 ppm//spl deg/C for Mg-doped GaN, respectively.