铁电材料以自发电极化为特征，具有铁电、介电、压电和热释电等功能特性；第三代半导体GaN由于其宽禁带、高电子饱和漂移速度、高热稳定性和高击穿场等被用于高频、高功率器件中。在GaN上外延生长氧化物铁电薄膜而构成人工新结构，会出现两类材料性能的调制耦合，为制备具有多功能集成及调制耦合新效应的电子器件提供新的思路。本项目拟在AlGaN/GaN上制备LiNbO3铁电薄膜，通过纳米尺度的ZnO缓冲层来实现界面态密度可控的外延生长；通过铁电畴取向控制,来实现界面极化电荷耗尽半导体沟道载流子，获得常关态的AlGaN/GaN增强型特征。并且研究铁电极化对沟道载流子输运特性作用机理；解决与半导体工艺相兼容的器件加工技术。因而，通过探索拟找到一种基于电极化作用的GaN基高迁移率晶体管（HEMT）增强型器件的新方法，以满足对高频、大功率GaN基电子器件的迫切需要。

Ferroelectric oxides with switchable polarization show multifunctional properties, such as ferroelectric, dielectric, piezoelectric and pyroelectric properties. GaN semiconductor with wide bandgap, high saturation velocity, high critical electrical field and good chemical and thermal conductivity has been widely used in high-power, high-frequency devices. The fabrication of artificial structures with epitaxial ferroelectric films on GaN will realize all-in-one multifunction and modulation of transport properties of semiconductors to accelerate the development of new electronic devices. In this proposal, LiNbO3 ferroelectric films will be integrated with AlGaN/GaN due to similar structure. Epitaxial growth will be realized by using nanometer-size ZnO bufferlayer to obtain low and controllable interfacial state density. The existing polarization charges by controlling ferroelectric domains at interface can deplete carriers in channel of AlGaN/GaN; and enhanced-mode characteristics with off-state at zero gate voltage can be observed. In addition, the modulation mechanism of ferroelectric polarization on carrier transportation in channel will also explored, and the device fabrication technology compatible with traditional semiconductor processing methods will be studied. Based on above-mentioned works, a new and more useful GaN-base HEMT (high-electron-mobility-transistor) fabrication method can be found to meet the impending demands on high-power, high-frequency GaN devices.