基于不同AlN钝化层的极性GaN MOS器件界面特性  

Interface Characteristics of Polar GaN MOS Devices Based on Different AlN Passivation Layers

作　　者：高森 武娴 肖磊 王敬[1] Gao Sen;Wu Xian;Xiao Lei;Wang Jing(Institute of Microelectronics,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学微电子研究所,北京100084

出　　处：《半导体技术》2021年第9期690-693,738,共5页Semiconductor Technology

基　　金：国家重点研发计划资助项目(2017YFB0404105)。

摘　　要：界面质量是影响GaN MOS器件性能以及可靠性的主要因素之一,Al2O3栅介质与极性GaN界面间插入超薄非晶AlN作为钝化层可以有效改善GaN栅界面特性,针对AlN钝化层生长方式研究了GaN界面优化特性。通过GaN MOS电容的C-V和J-V特性,结合透射电子显微镜(TEM)表征分析,对比了不同生长条件的AlN插入层对GaN MOS电容的界面特性的影响。相比常规热生长AlN钝化层制备的样品,以等离子体NH3为N源在300℃下生长AlN钝化层制备的GaN MOS电容的频散和滞回特性均得到显著改善,界面态密度也略有改善。分析认为,经过等离子体NH3的轰击作用有效地抑制了GaN表面上Ga—O键的形成,在GaN表面直接生长AlN,从而改善了界面特性。The interface quality is one of the main factors that affect the performance and reliability of GaN MOS devices.The characteristics of the GaN gate interface can be effectively improved by inserting ultra-thin amorphous AlN as a passivation layer between the Al2O3 gate dielectric and the polar GaN interface.Aiming at growth methods of the AlN passivation layer, the optimization characteristics of GaN interface were studied.Through the C-V and J-V characteristics of GaN MOS capacitors and combined with the transmission electron microscope(TEM) characterization and analysis, the effects of AlN insertion layers under different growth conditions on the interface characteristics of GaN MOS capacitors were compared.Compared with the sample prepared with the conventional thermally grown AlN passivation layer, the dispersion and hysteresis characteristics of the GaN MOS capacitor prepared by using plasma NH3 as the N source to grow the AlN passivation layer at 300 ℃ were significantly improved, and the interface state density was also slightly improved.The analysis shows that the bombardment of plasma NH3 can effectively inhibit the formation of Ga—O bonds on the GaN surface, allowing AlN to grow directly on the GaN surface, thereby improving the interface characteristics.

关 键 词：GaN MOS电容 AlN钝化层 界面态分析 等离子体NH3 C-V特性 

分 类 号：TN386.1[电子电信—物理电子学]