Title :
Gallium-Incorporated TiN Metal Gate With Band-Edge Work Function and Excellent Thermal Stability for PMOS Device Applications
Author :
Xu, Qiuxia ; Xu, Gaobo ; Liang, Qingqing ; Yao, Yuan ; Duan, Xiaofeng ; Li, Junfeng
Author_Institution :
Inst. of Micro Electron., Chinese Acad. of Sci., Beijing, China
Abstract :
A cost-effective method for modulating the effective work function (EWF) of a metal gate while simultaneously decreasing the equivalent oxide thickness (EOT) of a high-k dielectric is proposed for the first time. By incorporating gallium (Ga) into the TiN/HfLaON/interfacial layer (IL) SiO2 PMOS gate stack, a band-edge EWF of 5.18 eV and an EOT of 0.57 nm can be obtained. Excellent thermal stability was maintained even after the post metal anneal (PMA) at 1000°C. The impacts of TiN thickness, Ga implant doses, and PMA conditions on the properties of the Ga-incorporated TiN/HLaON/IL SiO2 gate stack are investigated, and the corresponding possible mechanisms are discussed. This technique has been successfully applied to the gate-first process flow to fabricate PMOSFETs with a minimum gate length of 28 nm.
Keywords :
MOSFET; gallium; hafnium compounds; high-k dielectric thin films; lanthanum compounds; semiconductor materials; semiconductor-metal boundaries; silicon compounds; thermal stability; titanium compounds; EOT; Ga-TiN-HfLaON-SiO2; PMOSFET; band-edge EWF; band-edge work function; electron volt energy 5.18 eV; equivalent oxide thickness; gallium-incorporated metal gate; gate-first process flow; size 0.57 nm; size 28 nm; temperature 1000 degC; thermal stability; Capacitors; Logic gates; MOSFETs; Thermal stability; Tin; Band-edge work function; HfLaON dielectric; PMOS device; gallium-incorporated TiN metal gate;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2011.2160147
