原子层沉积Al_2O_3/n-GaN结构的深能级界面态研究  

Study on the Deep-level Trap States at the Atomic Layer Deposited Al_2O_3/n-GaN Interface

作　　者：黄宇[1] 牟文杰[1] 闫大为[1] 杨国峰[1] 肖少庆[1] 顾晓峰[1] 

机构地区：[1]物联网技术应用教育部工程研究中心江南大学电子工程系,江苏无锡214122

出　　处：《固体电子学研究与进展》2016年第2期106-110,共5页Research & Progress of SSE

基　　金：国家自然科学基金资助项目(61504050);中国博士后科学基金资助项目(2013M540437);中央高校基本科研业务费专项资金(JUSRP51323B;JUSRP51510);江苏省六大人才高峰资助项目(DZXX-053)

摘　　要：基于与传统方法不同的物理过程,利用光辅助高频电容-电压(C-V)法研究了原子层沉积的Al_2O_3/nGaN界面的深能级缺陷态分布。无光照条件下的C-V曲线表现出典型的深耗尽行为,这主要由极长的深能级电子发射时间和极慢的少子热产生速率决定,可看作向正偏压方向平移了的理想电容曲线。在深耗尽状态下背入射365nm的紫外光后,大量的光生空穴有效地复合准费米能级以上的界面被陷电子,并允许电子在偏压扫描回积累区的过程中逐渐填充这些被排空的界面态,导致C-V曲线发生形变。基于上述物理过程,获得了一个快速衰减的界面态能级分布:从导带底至以下0.8eV,态密度从2.5×10^(12)cm^(-2)eV^(-1)减小至9×10^(10)cm^(-2)eV^(-1)。Based on a new physical process the distribution of deep-level trap states at the atomic layer deposited Al_2O_3/n-GaN interface was extracted by photo-assisted high-frequency capacitance-voltage(C-V)measurements.Due to the extremely long electron emission time and the extremely slow minority carrier generation rate,the C-Vcurve measured in darkness exhibited a typical deep depletion behavior,indicating unchanged occupancy states of these deep level interface traps,which could be regarded as an ideal C-Vcurve with a positive voltage shift.After the backside UV illumination of 365 nm under the deep depletion condition,the trapped electrons above the electron quasi-Fermi level could be effectively recombined by numerous photo-induced excessive holes,and the emptied interface states would be gradually refilled by electrons when the bias swept back to the accumulation state,resulting in a shape deformation of the C-Vcurve.Based on the above-described physical process,a rapidly decayed interface state distribution could be derived,indicating aquick decreasing density of states from 2.5×10^(12)cm^(-2)eV^(-1) at the conduction band edge to 9×10^(10)cm^(-2)eV^(-1) at 0.8eV below the conduction band edge.

关 键 词：Al2O3/n-GaN 原子层沉积 背入射紫外光照 电容特性 界面态分布 

分 类 号：TN304.2[电子电信—物理电子学]