HfO2/SrTiO3全氧化物场效应晶体管栅极漏电性质研究  

Gate leakage properties of HfO2/SrTiO3 all-oxide field effect transistor

作　　者：杨潇[1] 肖化宇 唐义强 曾慧中[1] 张万里[1] YANG Xiao;XIAO Huayu;TANG Yiqiang;ZENG Huizhong;ZHANG Wanli(State Key Laboratory of Electronic Thin Film and Integrated Devices,University of Electronic Science and Technology of China,Chengdu 611731,China)

机构地区：[1]电子科技大学电子薄膜与集成器件国家重点实验室,四川成都611731

出　　处：《电子元件与材料》2020年第9期56-61,共6页Electronic Components And Materials

基　　金：国家重点研发计划(2017YFB0406401);国家自然科学基金(51672035)。

摘　　要：基于等离子轰击和射频磁控溅射技术,制备了HfO2/SrTiO3结构的全氧化物场效应晶体管(FET),并研究了其栅极漏电性质。该全氧化物晶体管的制备工艺均在室温条件下完成,包括Ar+轰击在SrTiO3单晶表面产生的导电沟道,溅射生长非晶HfO2薄膜作为栅极介质层。实验发现溅射工艺中的氧分压对HfO2栅极漏电性质的影响显著。当氧氩分压比从1∶10增加到1∶2时,HfO2栅极的漏电密度明显降低。对变温漏电数据的分析表明,HfO2栅极的漏电以空间电荷限制电流(SCLC)机制为主导。对于低氧分压制备的栅极,其SCLC漏电机制的特征温度(Tt)和缺陷密度(Nt)分别为796 K和5.3×10^18 cm^-3。而氧分压提高后,栅极SCLC漏电的Tt降低为683 K,同时Nt下降为1.2×10^18 cm^-3。Tt的变化表明缺陷在禁带中分布发生变化,引起漏电-电压关系(J-Um)中的指数项m减小,有效地降低了栅极漏电,显著提高了HfO2/SrTiO3场效应晶体管的性能,使其开关比达到104。This article investigated the leakage properties of the all-oxide field-effect transistors(FET)based on HfO2/SrTiO3 structure,which was fabricated at room temperature.The conducting channel on the surface of SrTiO3 single crystal was formed by the Ar+bombardment.The amorphous HfO2 gate was deposited by radio frequency sputtering.The oxygen partial pressure during the sputtering plays a crucial role to determine the leakage property of HfO2 gate dielectrics.By increasing the oxygen partial pressure from 1∶10 to 1∶2,the leakage current density is reduced significantly.From 150 K to 300 K,the leakage of HfO2 gate dielectrics is dominated by space charge limiting current(SCLC).At lower oxygen partial pressure,the characteristic temperature(Tt)of SCLC and the defect density(Nt)are extracted to be 796 K and 5.3×10^18 cm^-3 respectively.By increasing the oxygen partial pressure,Tt is reduced to 683 K,and Nt is reduced to 1.2×10^18 cm^-3.Reduction of Tt is due to the change of trap distribution in energy band,which leads to the decrease of exponential term m(J-Um).The improvement of leakage is mainly caused by the change of exponential term m by increasing the oxygen partial pressure.This improves the performance of the HfO2/SrTiO3 FET,for example,with enhanced On-Off ratio up to 104.

关 键 词：非晶氧化物 场效应晶体管 漏电机制 空间电荷限制电流 缺陷 

分 类 号：TN386[电子电信—物理电子学]