A metal-ferroelectric-insulater-semiconductor structure (MFIS) was fabricated by depositing a Pb (Zr0.52T0.48)O3(PZT) film on the surface of the AlGaN/GaN template with MgO as a buffer layer by pulsed laser deposition(PLD). X-ray diffraction studies show that the preferred orientation growth of (111) PZT film on AlGaN/GaN heterostructure could be realized by inserting MgO buffer layer. From the I-V results,we can see that the electrical properties of the system has been greatly improved by the introducing of MgO buffer layer. Under the applied voltage of - 8V,compared with MFS,the leakage current density of MFIS has been reduced by five orders of magnitude. C-V curves exhibit counterclockwise memory windows which is induced by the ferroelectric polarization in PZT films. As the thickness of the buffer layer decrease, the modulation effect has increased. And the memory window increases to 0. 7V as the thickness of the buffer layer decreases to 2nm,the threshold voltage(Vth) move towards the positive direction to -1. 7V.%采用脉冲激光沉积(PLD)技术,以MgO作为缓冲层,在AlGaN/GaN半导体异质结构上沉积了Pb(Zr0.52T0.48) O3 (PZT)铁电薄膜,从而形成金属-铁电-介质-半导体结构(MFIS).XRD扫描结果表明,通过MgO缓冲层对界面结构的优化,实现了PZT薄膜沿(111)面择优取向生长.电流-电压(I-V )测试结果显示,MgO缓冲层的引入大大改善了集成体系的电学性能.在外加电压为-8V时,与无MgO缓冲层的MFS异质体系相比较,该MFIS结构的漏电流密度降低了5个数量级.集成体系的电容-电压(C-V)表现出逆时针窗口特征,反映了铁电极化对二维电子气(2DEG)的调制作用.随着缓冲层厚度的降低,铁电极化对2DEG的调制作用逐渐增强.当MgO缓冲层厚度达到2nm时,C-V窗口达到0.7V,阈值电压(Vth)降低到-1.7V,阈值电压(Vth)降低到-1.7V.
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