HIRF-SE KoM WPn - Title - · PDF fileHIGH-SPEED INTERCONNECTS First review thmeeting...

HIGH-SPEED INTERCONNECTSHIGH-SPEED INTERCONNECTS

First review meeting – Grenoble, 24th March 2009

CATHERINE Carbon Carbon nanotubenanotube

technology for hightechnology for high‐‐speed next speed next generation generation nanointerconnectsnanointerconnects

Cambridge 8th

April 2010

M.S. SartoSapienza Univ. of Rome

Research

Center on Nanotechnology

applied

to

Engineering

of Sapienza Univ.



Outline

Project objectives

Consortium

Workplan

Second year results

Conclusions



Project objectives

To develop an innovative cost‐effective and reliable technological solution for RF high‐performance nano‐interconnects

To achieve full control of morfology and properties of MWCNTs / CNFs

To understand and control RF properties for high‐frequency application (MMIC, RF MEMS) through modelling at different scales



Consortium1 (Coordinator) Consorzio

Sapienza Innovazione CSI

2Università

degli Studi di Roma “La Sapienza”

‐

Research

Centre

for

Nanotechnology

Applied

to

EngineeringSAPIENZA ‐

CNIS

3Technische

Universiteit

Delft –

Department of Precision

and Microsystem

EngineeringTUD

4 Universite

Paul Sabatier Toulouse III ‐

UPS UPS

5 Università

degli Studi di Salerno UNISAL

6 Latvijas

Universitates

Cietvielu

Fizikas

Instituts LU CFI

7National Institute for Research and Development in

Microtechnologies

‐

Microphysical Characterisation

And Simulation GroupIMT Bucuresti

8 Swedish Defence Research Agency FOI

9 Istituto Nazionale di Fisica Nucleare INFN

10 Philips Electronics Nederland B.V. PHILIPS

11 Smoltek

AB SMOLTEK



WorkplanWP1: Project management

WP2: Requirements and definitions

WP3: Modelling and simulation

WP4: Fabrication

WP5: Experimental characterization

WP6: Optimization of proof‐of‐concept interconnect

WP7: Dissemination and exploitation of results

Duration: 36 month

Concluded

at month

24



Second

year

resultsSimulation and modelling: •

Nano‐

and meso‐scale simulation models of growth mechanism and

validation

•

Modeling of electronic and electrical properties of CNTs

and their contacts with metals

•

RF and MW analysis

of MWCNT interconnects

•

Mechanical‐thermal

properties

•

Sensitivity

analysis

CATHERINE project data‐base available on line (www.catherineproject.eu): registration needed!

http://www.catherineproject.eu/



Second

year

resultsTwo fabrication approaches for realization of proof‐of‐conceptinterconnect:1.

CNTs

grown

inside porous

alumina

membrane without

catalyst

at ~

800°C

2.

CNFs

grown

from

Ni‐nanodots

at ~ 400°C

Experimental testing of fabricated nanomaterials:•

Microscale characterizations

•

Electrical

and EM properties:o

Effective

permittivity

of porous

alumina

membrane (from

dc

to

50 GHz)

o

Effective

dc

conductivity

of CNTs

and CNFs

•

Mechanical

characterizations



Modelling

of MWCNT‐

interconnect

Generalized

model of the number

of conducting

channels

of a CNT shell

as

function

of temperature

and shell

chirality.

New equivalent

multiconductor

circuit including

all

mutual

parameters:

L'e(s,s)dz

C'q (s,s)dz

C'e(s,s)dz

C'q (1,1)dz

C'q (2,2)dzC'e(1,2)dz

C'e(s-1,s)dz

C'e(2,3)dz

L'm(s-1,s)dzL'm(2,3)dzL'm(1,2)dzL'k (1,1)dzR'(1,1)dz

L'e(s,s)dzL'm(s-1,s)dzL'm(2,3)dzL'k (2,2)dzR'(2,2)dz

L'e(s,s)dzL'k (s,s)dzR'(s,s)dz

k=1

k=1

k=1k=1k=1

s

2

1

nanotube shell diameter d, nm

Nch

d0(T,V) – crossover scale

(met)

(sem)


Nch


Nch

d0(T,V) – crossover scaled0(T,V) – crossover scale

(met)

(sem)

(met)

(sem)

Metal‐to‐CNT contact resistance from scattering

theory:

Au Pt

Pd

AgCu

Ni

0

1

2

3

4

5

1

Metal

R, k

Ohm



NEW ESC model from analytical developments:

•

Analtical

“exact”

expression

of the effective

quantum parameters.•

Simplified

approximated

expressions

for

quick

analysis.

•

Very

accurate up to

several

tens

of GHz.

NEW Equivalent Single Conductor p.u.l. circuit

M.S. Sarto, A. Tamburrano, “Single‐Conductor

Transmission Line Model of Multiwall

Carbon

Nanotubes”, IEEE Trans. on Nanotechnology, Jan. 2010.

1

, kk k

1 tot

ˆ 12

sj j

j

LL L

n

−

=

⎡ ⎤ ′′ ′= =⎢ ⎥

⎣ ⎦∑

q 1C s rα β γ′ = + +

r1

in [nm], and α=2.56⋅10-2

[nF/m], β=7.525⋅10-2

[F/m2], γ=9.887⋅10-2

[nF/m].

s

2 4 6 8 10 12 14 16 18 20

C' q ;

C' q [

nF/m

]

0

1

2

3

4

5

r1 = 50 nm

r1 = 20 nm

r1 = 5 nm

r1 = 0.5 nm

^˜



S

G

G

MWCNT

Substrateεr = 4

6 μm

w

3 μm

0.5 mm

ww

w = 50 μm

10 μm

150 μm

MWCNT

r15

r1

[1] Gael F. Close, H.-S. Philip Wong, “Assembly and electrical characterization of multiwall carbon nanotube interconnects”, IEEE Transactions on Nanotechnology, Vol. 7, No. 5, September 2008

MWCNT:•

outer radius: 40 nm•

shells number: 15•

equivalent d.c. resistance: 7 kΩ

Parasitics

computed

by

full-wave

EM calculations:Csg

= 7.71·10-15

F and Css

= 1.14·10-15 F

Mea

sured

Mea

sured

0 5 10 15frequency (GHz)

-30

-40

-50

-60

S21

(dB

)

7 kΩ

open


-30

-40

-50

-60

S21

(dB

)


-30

-40

-50

-60

S21

(dB

)

7 kΩ

open

Compu

ted

Compu

ted

Model validation1



CATHERINE DATA BASE

The data‐base includes:•

All

models

developed

within

CATHERINE project

Executable filesUser guideReport and model description

The data‐base is on‐line and validated•

Beta‐version

published

on Dec. 31, 2009

•

Periodical

maintenance•

Final release

at month

36



CATHERINE Project Data‐Basewww.catherineproject.eu




Fabrication

approach

no.1

CNTs

grown

inside porous

alumina membrane without

catalyst

at ~ 800°C



Fabrication of alumina membrane

Stand alone AAO

membrane

Pore

diameter

> 200 nm

Pore

diameter

< 50 nm

AAO thin film on Nb

coated

Si‐ wafer



High frequency

permittivity

measurements

l

w g

s

wgs

250s [um]

60 - 1005; 1050500 -1000H [um]g [um]w [um]l [um]

250s [um]

60 - 1005; 1050500 -1000H [um]g [um]w [um]l [um]

Gold

Alumina

H

Sapienza‐CNIS

•

MicroProbe

station Cascade: enviroment

free from moisture and frost; shielded against

electromagnetic and electrostatic interferences (d.c. – 67 GHz)•

VNA Agilent

PNAX 4 ports

–

10 MHz

‐

50 GHz

Test fixture:

Alumina

membrane:

pore

diameter

~ 200

nm; thickness: 60

μm



o O O O o o o O O o o O o o O

o O o o

C2H2/He

C2H4/He

CH4/He

H2

1

He

23 4

Control Unit MFC H2O He/Air

M.F.C

T.C

BYPASS

Discharge

C2H4H&B

H2

ANALYZERS

COMPUTER

CH4

C2H2H&B

H&B

H&B

H&B

Co O O O o o o O O o o O o o O

o O o o

o O O O o o o O O o o O o o O

o O o o

C2H2/He

C2H4/He

CH4/He

H2

1

He

23 4

Control Unit MFC

C2H2/He

C2H4/He

CH4/He

H2

1

He

23 4

C2H2/He

C2H4/He

CH4/He

H2

1

He

23 4

C2H2/He

C2H4/He

CH4/He

H2

1

He

23 4

C2H2/He

C2H4/He

CH4/He

H2

1

He

C2H2/He

C2H4/He

CH4/He

H2

1

He

23 4

Control Unit MFC Control Unit MFC H2O He/Air

M.F.C

T.C

BYPASS

Discharge

T.C

BYPASS

Discharge

T.C

BYPASS

Discharge

T.C

BYPASS

Discharge

T.C

BYPASS

Discharge

T.C

BYPASS

Discharge

T.C

BYPASS

Discharge

T.CT.C

BYPASS

Discharge

C2H4H&B

H2

ANALYZERS

COMPUTER

CH4

C2H2H&B

H&B

H&B

H&B

C

Experimental apparatus for CVD

Thermocouple

Aluminamembrane

Sinteredsupport

C2H4/N2 flow

Isothermal zone

Exhaust flow

Inlet flow

Thermocouple

Aluminamembrane

Sinteredsupport

C2H4/N2 flow

Isothermal zone

Exhaust flow

Inlet flow

0

2

4

6

0 200 400 600 800 1000 1200 1400

time (sec)

% (v

/v)

CH4C2H4H2C2H2

On-line analysis of exhaust gas during CNT growth

Flow reactor for CVD

CNT growth without catalyst



SEM image by UPS of CNTs emerging from alumina membrane



TEM image of CNTs after membrane removal by HF



DC volume conductivity of CNTs grown inside Alumina membrane without catalyst

Silver conductive paint:•

Electrolube; Volume conductivity: ~ 9 kS/cm

Conductive silver epoxy:•

Circuit Works Conductive Epoxy CW2400 Chemtronics;

Volume resistivity: ~ 1.7 mΩ cm

DC Current SourceNanovoltmeterNanovoltmeter

Metallic (Cu)electrode

Silver conductive epoxy

Dielectric ring

Silver paint

Alumina membrane Rtop

RCNT_totRborder

Rbottom

Rtop

RCNT_totRborder RCNT_totRborder

Rbottom

Total measuredresistance: R=65.77 m Ω

Estimated volume resistivity of a CNT: ρCNT ≈ 3.85 mΩ cm



Fabrication

approach

no.2

CNFs

grown

from

Ni‐nanodots at ~ 400°C



Developed activitiesDeveloped activities

Die

attachment

technique

to prepare

top contact with

the

grown

CNF

Contacts

realization:



h

DC volume conductivity of CNFs produced on silicon wafer from Ni-nanodots

Geometry for die attach method:L = 3.5 mmwc

= 0.12 mmd = 0.7 mmA = L wc

= 0.42 mm2

t = 50 nm Tungsten Fill factor of CNF at bottom ≈

13%

Geometry for conical CNF:

b ≈

19.5 nmB ≈

55.5 nm

h ≈

1.4 -

1.5 μm

b

B

h



Electrical

resistivity

of a single CNF

Total measured resistance: R=0.81Ω

Total estimated volume resistivity of a CNF: ρCNF≈ 4.40 mΩ cm

Rc

/2

RCNT_tot

/2

Rground

Rc

/2

RCNT_tot

/2

CNT 90

0° 90

0° 90°

acos 19.25

0.04 m cm, 40 m cm

ρ ραρ ρ

ρ ρ

°

°

⎡ ⎤−= = °⎢ ⎥

−⎢ ⎥⎣ ⎦= Ω = Ω

Graphitic plane orientation1:

1) L.

Zhang, et

al., “Four-probe charge transport measurements on individual vertically aligned carbon nanofibers”, Applied

Phisics

Letters, Vol.

84, No. 20, 17 May

2004.



ConclusionsActivity are in line with DOW

New multiscale models for RF and MW analysis of MWCNT interconnects

CATHERINE project data‐base available on line (www.catherineproject.eu): registration needed!Growth of MWCNTs / CNFs with controlled morphologyusing two different approaches:•

CNTs

grown inside porous alumina membrane without catalyst at ~

800°C

•

CNFs

grown from Ni‐nanodots

at ~ 400°C

Obtained results in line with planned third year activity•

Optimization of processes

•

Fabrication and testing of proof‐of‐concept nano‐interconnects


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