Fabrication and characterization of metal-ferroelectric-GaN structures

GaN-based metal-ferroelectric-semiconductor (MFS) structure has been fabric ated by using ferroelectric Pb(Zr0.53Ti0.47)O-3 (PZT) instead of convention al oxides as gate insulators. The GaN and PZT films in the MFS structures h ave been characterized by various methods such as photoluminescence (PL), w ide-angle X-ray diffraction (XRD) and high-resolution X-ray diffraction (HR XRD). The Electric properties of GaN MFS structure with different oxide thi ckness have been characterized by high-frequency C-V measurement. When the PZT films are as thick as 1 mum, the GaN active layers can approach inversi on under the bias of 15V, which can not be observed in the traditional GaN MOS structures. When the PZT films are about 100 nm, the MFS structures can approach inversion just under 5V. All the marked improvements of C-V behav iors in GaN MFS structures are mainly attributed to the high dielectric con stant and large polarization of the ferroelectric gate oxide.