AlN film using low temperature MOCVD process for FBAR

Film bulk acoustic resonator (FBAR) was fabricated using AlN(0002) film. We achieved the high oriented AlN(0002) film through the metal-organic chemical vapor deposition (MOCVD) method on Ru/Ta bottom electrode. But thermal stress of AlN film was a problem in the high temperature MOCVD process over 1000degC. To reduce the thermal stress of AlN film, the low temperature AlN film growth was needed. We investigated the influence of H₂ and N₂ carrier gas in the MOCVD process to the AlN film quality. The full width at half maximum (FWHM) of the AlN(0002) using the N₂ carrier gas was better than that of the H₂ gas at the low temperature. Then the AlN cracks was reduced by the low temperature AlN growth. Furthermore, the FWHM of AlN(0002) using H₂ and N₂ gases at the MOCVD method were excellent value of under 1.5deg at less than 0.5 mum thickness.