Etch Profile Control of W/TiN/HfSiON and W/TaSiN/HfSiON Full-Metal Gates

Endo

et al. 2014

Jpn. J. Appl. Phys.

Influence of work function variation (WFV) in metal gates (MGs) on fluctuation of sub-threshold drain current is investigated in detail by analyzing fluctuation of current–onset voltage (COV) for fin field-effect transistors (FinFETs) with polycrystalline TiN and amorphous TaSiN MGs. The polycrystalline TiN MG exhibits anomalously increased COV fluctuation of the nMOS FinFETs in comparison to the pMOS case, while the amorphous MG exhibits well suppressed COV fluctuation both for the n- and pMOS FinFETs. Through the discussion with regard to the WFV due to the polycrystalline TiN grains, it is concluded that the sub-dominant grains of TiN with lower work function (WF) in TiN form localized potential valleys in the channel of the nMOS FinFETs resulting in the anomalous leak current in the sub-threshold condition. In the pMOS FinFETs, in contrast, the lower WF grains in TiN form localized potential peaks for holes, which have less impact on the sub-threshold leakage.

Section: Sample Finfet Fabricationmentioning

confidence: 89%

Influence of work function variation of metal gates on fluctuation of sub-threshold drain current for fin field-effect transistors with undoped channels

Endo

et al. 2014

Jpn. J. Appl. Phys.

“…As a material of the amorphous MG, TaSiN was used because of its thermal stability and suitability for a gatefirst process. 9,[14][15][16] The TaSiN thin film was deposited by sputtering a Ta 67 Si 33 alloy target with N 2 =Ar plasma, in which the N 2 =Ar flow ratio was set at 2%. A polycrystalline TiN gate, which is commonly investigated as a gate-first MG, [17][18][19][20] was also examined for comparison.…”

mentioning

confidence: 99%

Impact of granular work function variation in a gate electrode on low-frequency noise for fin field-effect transistors

Fukuda

et al. 2015

Appl. Phys. Express

The impact of work function variation (WFV) in a metal gate (MG) electrode on low-frequency noise (LFN) is revealed for fin field-effect transistors (FinFETs). The LFN level is compared between the FinFETs having polycrystalline TiN and amorphous TaSiN MGs. The amorphous TaSiN MG exhibits a marked suppression of flicker noise in comparison with the TiN MG. The difference in the LFN level is correlated with the threshold voltage variability reflecting the WFV of the MG. By modeling the WFV of the TiN MG in the FinFET structure by three-dimensional device simulation, we clearly reveal the mechanism of the LFN increase by the WFV.

Suppression of threshold voltage variability of double-gate fin field-effect transistors using amorphous metal gate with uniform work function

Applied Physics Letters

Mizubayashi

et al. 2013

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