# 접합 및 무접합 이중게이트 MOSFET에 대한 문턱전압 이동 및 드레인 유도 장벽 감소 분석

• Jung, Hak Kee (Department of Electronic Engineering, Kunsan National University)
• 정학기 (군산대학교 전자공학과)
• Accepted : 2018.12.03
• Published : 2019.03.01

#### Abstract

An analytical threshold voltage model is proposed to analyze the threshold voltage roll-off and drain-induced barrier lowering (DIBL) for a junction-based double-gate (JBDG) MOSFET and a junction-less double-gate (JLDG) MOSFET. We used the series-type potential distribution function derived from the Poisson equation, and observed that it is sufficient to use n=1 due to the drastic decrease in eigenvalues when increasing the n of the series-type potential function. The threshold voltage derived from this threshold voltage model was in good agreement with the result of TCAD simulation. The threshold voltage roll-off of the JBDG MOSFET was about 57% better than that of the JLDG MOSFET for a channel length of 25 nm, channel thickness of 10 nm, and oxide thickness of 2 nm. The DIBL of the JBDG MOSFET was about 12% better than that of the JLDG MOSFET, at a gate metal work-function of 5 eV. It was also found that decreasing the work-function of the gate metal significantly reduces the DIBL.

#### File

Fig. 1. Schematic cross sectional diagram of double gate (DG) MOSFET.

Fig. 2. Eigenvalue λn under given conditions. We show the value of sinh (πLgn), denominator of potential distribution function.

Fig. 3. Comparison of threshold voltage roll-offs for this model and TCAD simulation [3] under given conditions. The line and dots denote results of this model and TCAD, respectively.

Fig. 4. Comparison of threshold voltage roll-offs for JBDG MOSFET (Na = 5 × 1019 / cm3 ), undoped channel DGMOSFET, and JLDGMOSFET (Nd = 5 × 1019 / cm3 ) at (a) Vds = 0.1 V and (b) Vds = 1.0 V .

Fig. 5. Threshold voltage roll-offs for doping concentraion (a) with channel thickness as a parameter and (b) with oxide thickness as a parameter under given conditions.

Fig. 6. DIBLs for doping concentration under given conditions at channel length of 25 nm with silicon and oxide thickness as parameters.

Fig. 7. DIBLs for doping concentration under given conditions at channel length of 25 nm with gate workfunction as a parameter.

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