Recent Enhancements in BSIM6 and BSIM-CMG model

Yogesh S. Chauhan*, Juan P. Duarte, Harshit Agarwal*, Sourabh Khandelwal, Chenming Hu

*IIT Kanpur, IndiaUniversity of California, Berkeley

MOS-AK Berkeley

Outline

BSIM6 Updates Flicker Noise Model for Halo Implanted FETs Double Hump Modeling

BSIM-CMG Updates Modeling FinFETs with complex cross-sections (on SOI and

Bulk substrates) Improved speed and robustness New body-bias effect model Modeling InGaAs FinFETs Modeling Ge FinFETs

MOS-AK Berkeley UC Berkeley - 2

Flicker (1/f) Noise Flicker noise: the fluctuation of drain current due to

trapping/detrapping of charge carriers. There are two main theories to explain origin of flicker noise:

McWhorter model: fluctuation in the number of carriers due to trapping.

Hooge’s model: fluctuation in mobility due to phonon scattering Unified model: Trapped charges give rise to a fluctuation in

the number of carriers as well as alter mobility.Gate

Oxide

Source Drain

Donor typeAcceptor type

MOS-AK BerkeleySource: C. Sanabria, PhD Dissertation, UCSB, 2006 UC Berkeley - 3

Double Hump Modeling

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Problem Statement

• Double Hump in device characteristics

• What is the source of double hump?

• How to model this effect in BSIM6?

• In most accurate and efficient way

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Double Hump TCAD Analysis

Cut along

Channel Length

Cut along Width

Cut along Length

Source

Gate

S D

G

STI

G

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Model Testing Results

Model Passes Gummel Symmetry Tests

Continuous and Smooth Derivatives

ID Vs VxGM Vs Vx

GM’ Vs Vx GM’’ Vs Vx

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Outline

BSIM6 Updates Flicker Noise Model for Halo Implanted FETs Double Hump Modeling

BSIM-CMG Updates Modeling FinFETs with complex cross-sections (on SOI and

Bulk substrates) Improved speed and robustness New body-bias effect model Modeling InGaAs FinFETs Modeling Ge FinFETs

MOS-AK Berkeley UC Berkeley - 8

FinFET’s Various Complex Cross-SectionsSTMicroelectronics, VLSI 2012

TSMC, IEDM 2010

IBM, VLSI 2012

Toshiba, VLSI 2012

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1. Double-Gate FinFET:

2. Cylindrical FinFET:

Charge Equation :

Charge Equation:

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Prior Models Available for Two Simple Cross-Sections Only—Deductive model

various Fin shapes SEM or imagined

Model Parameters: Unified Model forFin Area: AchChannel Doping:NchChannel Width: WInsulator Cap: Cins

11

New Unified Model for Complex FinFET Cross-Sections – Inductive model

( )

−−

+−+−=−− − 1lnln

2

tq

tmmCHOG qe

qqqvvvt

−−=

chinsT

chidepFBO NCv

Aqnqvv22ln ( ) 2W

CAqqqch

inschdepmt ε

+=

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Modeling InGaAs FinFETs

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InGaAs FinFET Modeling BSIM-CMG with the new Quantum Effects

model used to model InGaAs FinFETs

Data from: J. J. Gu et al. IEDM 2012

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L = 20 nm, H = 30 nm, W = 20 nm, Nfin = 4.

S. Khandelwal et. al., WCM 2014

InGaAs FinFET Modeling

Data from: J. J. Gu et al. IEDM 2012

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L = 20 nm, H = 30 nm, W = 20 nm, Nfin = 4.

S. Khandelwal et. al., WCM 2014

InGaAs FinFETs with Triangular Cross-section

T. Irisawa et al. IEDM 2013Importance of accurate modeling of Quantum Effects

MOS-AK Berkeley UC Berkeley - 15S. Khandelwal et. al., WCM 2014

Modeling Germanium FinFETs

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Modeling Germanium FinFETs with BSIM-CMG

User selectable MOD to model Ge FinFETs Material Mode “MTRLMOD” = Si (Default) or Ge

“MTRLMOD”=Ge invokes new mobility model for Ge MTRLMOD = Ge sets key parameters for Ge

Band-Gap, Mobility … MTRLMOD=Ge model verified with experimental data

Excellent Model Calibration Results Scalable Ge FinFET Model

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BSIM-CMG Model Results for Ge pFinFETs

L = 130 nm

MOS-AK Berkeley UC Berkeley - 18S. Khandelwal et. al., IEEE EDL 2014

Germanium Mobility Model

Surface Roughness affects Ge mobility at a higher Eeff

Accurate Modeling of Non-linearity needs improved mobility model

MOS-AK Berkeley UC Berkeley - 19S. Khandelwal et. al., IEEE EDL 2014

Summary BSIM6

Updated with new noise model Double hump modeled using Edge-FET Receiving continuous updates with industry feedback

BSIM-CMG Demonstrated excellent results for complex Fin

shapes A new FinFET body-bias effect model A new Quantum Effect model Modeling of InGaAs and Germanium channel material Model speed improvement ~ 30%

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