The investigation of d.c. magnetron reactively sputtered AlN films applied to GaAs devices passivation

An AlN film has been deposited by d.c. magnetron reactive sputtering. The stoichiometry, dielectric constant, breakdown strength, density, refractive index and stress of the films were measured. The surface roughness of the AlN film was studied by atomic force microscopy (AFM). The deposition process induced damage of GaAs substrate was also studied. The AlN/GaAs interface was analyzed by Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). At the AlN/GaAs interface, the O-Al bond was found and O-Ga or O-As bonds were not found. The AlN film was applied to GaAs power MESFET passivation. The d.c. parameters of the device: BV_GD, loss and V_p did not change after passivation. The device passivated by AlN also showed good r.f. properties