Novel V<inf>th</inf> tuning process for HfO<inf>2</inf> CMOS with oxygen-doped TaC<inf>x</inf>

Effect of Y Content in (TaC)1-xYx Gate Electrodes on Flatband Voltage Control for Hf-Based High-k Gate Stacks

“…The large m,eff (4.7 eV) of the pure TaC gate is due to the effect of the oxygen content (about 10%) in the TaC, as previously reported. 10) Indeed, m,eff can be low if oxygen is eliminated from the sputtering system. The V fb changes of the (TaC) 1Àx Y x -gated MOS capacitors with 4.2-and 4.9-nm-thick HfO 2 films are shown in Fig.…”

“…6) Metal carbides, such as TaC, HfC, and HfCN, with a sufficient thermal stability and a low effective work function ( m,eff ), have been reported to be promising gate electrodes for nMOSFETs. [6][7][8][9][10] Indeed, interest in nitrogen-free TaC-based materials has especially increased because of their high mobility. 6,7,10) However, these materials are insufficient for a n-metal gate electrode because m,eff displays a wide range (4.2-4.9 eV).…”

“…[6][7][8][9][10] Indeed, interest in nitrogen-free TaC-based materials has especially increased because of their high mobility. 6,7,10) However, these materials are insufficient for a n-metal gate electrode because m,eff displays a wide range (4.2-4.9 eV). 10) Therefore, we expect that a lower m,eff could be obtained by introducing an yttrium (Y) atom with a low work function of 3.1 eV into TaC materials.…”

(Invited) Band-Edge Effective Work Functions by Controlling HfO2/TiN Interfacial Composition for Gate-Last CMOS

“…The control of the effective work function (EWF) of metal gates on Hf-based gate dielectrics has proven to be a difficult task (1,2). Techniques such as capping layers and anneals have been used to manipulate the metal/dielectric interface and modify the work function (3)(4)(5)(6)(7)(8)(9)(10)(11). Local dipoles created via these techniques can greatly affect the electrostatic potentials resulting in near band edge effective work functions (12).…”