脉冲激光沉积氮化铝薄膜的电学性能研究

Electrical properties of AlN films prepared by pulsed laser deposition

采用脉冲激光沉积(PLD)技术在硅片上合成了A lN薄膜。X射线衍射(XRD)结果证实制备的A lN薄膜具有(002)择优取向的六方纤锌矿晶体结构,并且结晶质量随Si衬底温度的提高而改善。电流-电压(I-V)、电容-电压(C-V)、极化曲线结果表明室温生长的A lN薄膜的击穿场强约2.5MV/cm,同时呈现明显的极化现象(类铁电),对应矫顽场强为150kV/cm,剩余极化为0.002C/m2。晶态A lN存在较强的自发极化,薄膜中可动电荷密度高,据此提出了动态电荷模型,指出较大的A lN薄膜极化回线是由于可动电荷在电场中的再分布形成的,因而有别于铁电材料。

AlN films were synthesized on Si substrates by tion （XRD） spectra show that the films have a （002） pulsed laser deposition （PLD）. X - ray diffracoriented hexagon wurstite crystalline structure and the crystallinity becomes better with higher substrate temperature. Current - voltage （ I - V）, capacitance - voltage （ C - V） and polarization measurements demonstrate that the room - temperature grown sample has a breakdown field of 2.5MV/cm, and also a clear polarization hysteresis. Based on the intrinsic large spontaneous polarization in crystalline AlN and the large dynamic charge density in the samples.