高k金属栅NMOSFET器件阈值电压调控方法  

Control Method of the Threshold Voltage for High-k Metal Gate NMOSFET Devices

作　　者：刘城 王爱记 刘自瑞 刘建强 毛海央[3] Liu Cheng;Wang Aiji;Liu Zirui;Liu Jianqiang;Mao Haiyang(School of Microelectronics,University of Chinese Academy of Sciences,Beijing 101408,China;Semiconductor Manufacturing North China Corporation (SMNC),Beijing100176,China;Institute of Microelectronics ,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]中国科学院大学微电子学院,北京101408 [2]中芯国际集成电路制造(北京)有限公司,北京100176 [3]中国科学院微电子研究所,北京100029

出　　处：《微纳电子技术》2019年第1期13-19,25,共8页Micronanoelectronic Technology

摘　　要：实现对器件阈值电压的有效调控是高k金属栅(HKMG)技术面临的一项重要挑战。TiAl薄膜作为n型金属氧化物半导体场效应晶体管(NMOSFET)的功函数层被广泛地应用于HKMG结构中以实现对器件阈值电压的调控。实验采用射频(RF)-直流(DC)磁控溅射的方式沉积TiAl薄膜,通过优化直流功率、射频功率和反应压强工艺参数,实现了对薄膜Ti/Al原子比率的调节,提高了Ti/Al原子比率分布均匀度。基于实验结果,采用后栅工艺流程制造HKMG NMOSFET,讨论不同的Ti/Al原子比率和TiAl层厚度对NMOSFET阈值电压的影响。Ti/Al原子比率增大10%,NMOSFET的阈值电压增加12.6%;TiAl层厚度增加2 nm,NMOSFET的阈值电压下降19.5%。这种方法已经被成功应用于HKMG器件的生产。Effective control of device threshold voltages is a tough challenge for the high-k metal gate(HKMG)technology.The TiAl film as a work function layer of n-type metal oxide semiconductor field effect transistor(NMOSFET)was used in the HKMG structure to control the device threshold voltage.The TiAl film was prepared using the radio frequency(RF)-direct current(DC)magnetron sputtering technique.By optimizing the DC power,RF power and reaction pressure,the adjustment of Ti/Al atomic ratio was achieved,and the uniformity of Ti/Al atomic ratio was improved.Based on the experimental results,the HKMG NMOSFET was fabricated by the gate-last process.The impacts of different Ti/Al atomic ratios and TiAl layer thicknesses on the threshold voltage of the NMOSFET were discussed.With the Ti/Al atomic ratio increases by10%,the threshold voltage of the NMOS increases by 12.6%.With the increase of the TiAl layer thickness for 2 nm,the threshold voltage of the NMOSFET decreases by 19.5%.The method has been successfully used in the production of the HKMG devices.

关 键 词：高k金属栅(HKMG) 功函数层 磁控溅射 Ti/Al原子比率 阈值电压 n型金属氧化物半导体场效应晶体管(NMOSFET) 

分 类 号：TN386.1[电子电信—物理电子学]