Growth of AlN film on Mo/SiO2/Si (111) for 5 GHz-band FBAR using MOCVD

We fabricated a film-bulk-acoustic resonator with high c-axis oriented AlN film on Mo/SiO₂/Si (100) using metalorganic chemical vapor deposition. The resonant frequency and anti-resonant frequency of the fabricated resonator were 3.189 GHz and 3.224 GHz, respectively. The quality factor and the effective electromechanical coupling coefficient were 24.7 and 2.65%, respectively. The conditions of AlN deposition were substrate temperature of 950°C, pressure of 20 torr, and V-III ratio of 25000. We have successfully grown high c-axis oriented AlN film with 4×10^-5 Ωcm resistivity of the Mo bottom electrode. The full width at half maximum (FWHM) of the AlN (0002) on Mo/SiO₂/Si (100) and Mo/SiO₂/Si (111) were 4° and 3.8°, respectively. The FWHM values of the deposited AlN film satisfy the RF band pass filter specification for GHz-band wireless local area network.