5 Presentation ALD2012 StefanMueller Data July 2013 CITATIONS - - PDF document

5 Presentation ALD2012 StefanMueller

• A. Singh

Slide 1

Stefan Müller1, Johannes Müller2, Aarti Singh1, Stefan Riedel2, Jonas Sundqvist2, Uwe Schröder1 and Thomas Mikolajick1

Fe Ferroe

• elec

lectric ric Ph Phase e Tr Transitio sitions ns in Po Poly-Cry rystall stallin ine e Al Al:HfO fO2-Th Thin in Fi Films

1 2

18.06.2012

Slide 2

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Outlin line: e:

• Motiva

ivatio tion: n: Why Hf HfO2?

• Ex

Experim rimen ental tal: : Al Al:HfO fO2 Capaci citor tors

• El

Electr ctrica ical l / Ph Physica ical l Ch Charac acter teriza ization

• n
• Immedi

diate ate Ap Applic icati ations ns

• Su

Summary

• - -

• + -

Slide 3

Motivation: Why HfO2? CMOS S Transi nsistors stors DRAM Capacitors itors

Panasonic 32 nm HKMG Winbond 65 nm DRAM

Drain n Curren ent  COX

OX 

Signal al Charge  COX

OX 

COX

OX =

= 0

0 r r A / d

Si SiO2 k k  4 HfO2 k k  20 20 r  “k“

18.06.2012

Slide 4

Motivation: Doping HfO2 for higher-k phase stabilization Amorphous HfO2 High-symme symmetry try / / high-k k phases es Low Low-symmetry symmetry / / lower-k k phase 1 Anneal Monoclinic P21/c Tetragonal P42/nmc Cubic Fm3m 2 Anneal + Doping Stabilizing dopants (see literature):

Figures: A. Navrotsky, “Thermochemical insights into refractory ceramic materials based on oxides with large tetravalent cations”, J. Mater. Chem. 15 15, 1883 (2005)

13 Al 14 Si 21 Sc 38 Sr 39 Y 40 Zr 64 Gd 66 Dy …

Non Non-cent entrosy rosymm mmetr etric / / ferroelec electr tric phase

Orthorhombic Pbc21 + “Homeopathic” Doping

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13 Al 14 Si 39 Y

?

Slide 5

Experimental: Fabrication of Al:HfO2 PMA and PDA Capacitors

800°C / 1000°C PMA + Pt Dots 800°C / 1000°C PDA + Pt Dots Silicon CVD-TiN 3 h at 450 °C 10 nm ALD - Al:HfO2 Tdep = 275 °C 16 nm (TEMAH:TMA) Pt (5 nm Ti adhesion layer) 30 nm 11.4 mol% Wet etch PMA = “Post-Metallization-Anneal” PDA = “Post-Dielectric-Anneal”

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8.5 mol% 7.1 mol% 4.8 mol% 3.1 mol% HfO2

• S. Mueller et al., “Incipient Ferroelectricity in Al-Doped HfO2 Thin Films”, Adv. Func. Mat. 22

22, 2412 (2012)

Slide 6

Experimental: Process Control and Thin Film Quality

0.05 0.1 0.15 5 10 15 20 25 5 10 15 20 0.00 0.05 0.10 0.15 AlO1.5 content[mol%] ALD cycle ratio [Al/(Al+Hf)]

(b)

Control rollab abili lity ty of

• f ALD-Process

Process

0.0 0.5 1.0 8 16

8 16 0.2 0.4 0.6 0.8 1 Height [nm] Lateral Dimension [µm]

PMA

Surface face Roughness ness: AFM

0.0 0.5 1.0 8 16

8 16 0.2 0.4 0.6 0.8 1 Height [nm] Lateral Dimension [µm]

PDA

Al:HfO HfO2 (16 nm nm) TiN (10 nm nm) TEM TiN (10 nm nm) Si Si (Bulk) k)

18.06.2012

• S. Mueller et al., “Incipient Ferroelectricity in Al-Doped HfO2 Thin Films”, Adv. Func. Mat. 22

22, 2412 (2012)

Slide 7

Results: Electrical Polarization Measurements (PMA Capacitors) 7.1 mol% 1000 1000 °C 800 800 °C 450 450 °C 11.4 mol% 8.5 mol% 4.8 mol% 3.1 mol% 1000 1000 °C 4.8 mol%

18.06.2012

• S. Mueller et al., “Incipient Ferroelectricity in Al-Doped HfO2 Thin Films”, Adv. Func. Mat. 22

22, 2412 (2012)

• 4 E [MV/cm] +4
• 40 P [µC/cm2] +40

Slide 8

Results: Electrical Polarization Measurements (PDA Capacitors) 7.1 mol% 1000 1000 °C 800 800 °C 11.4 mol% 8.5 mol% 4.8 mol% 3.1 mol% PDA: : Electrica ctrical chara ract cteriza rizatio tion limite ited d by by breakdown kdown of

• f capacitors

citors!

18.06.2012

• S. Mueller et al., “Incipient Ferroelectricity in Al-Doped HfO2 Thin Films”, Adv. Func. Mat. 22

22, 2412 (2012)

• 4 E [MV/cm] +4
• 40 P [µC/cm2] +40

Slide 9

0.3 0.4 0.5 0.6 0.7 0.8

• 6
• 4
• 2

2 4 6 Capacitance [nF] Voltage [V]

11.4 mol% 8.5 mol% 7.1 mol% 4.8 mol% 3.1 mol%

Results: Additional Characteristics of the Thin Films r / / Pr vs. mol% C-V-Chara ract cteris ristics tics

3.1 4.8 7.1 8.5 11.4

15 20 25 30 35 40 2 4 6 8 3.1 4.8 7.1 8.5 11.4 Relative Permittivity [1]

• Rem. Polarization [µC/cm2]

Aluminum Concentration [mol%] 18.06.2012

• S. Mueller et al., “Incipient Ferroelectricity in Al-Doped HfO2 Thin Films”, Adv. Func. Mat. 22

22, 2412 (2012)

Slide 10

Results: Additional Characteristics of the Thin Films cont’d Leakage and and Breakd kdown wn

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• 7.0
• 3.5

0.0 3.5 7.0 Current [A] Voltage [V]

11.4 mol% 8.5 mol% 7.1 mol% 4.8 mol% 3.1 mol%

100 10-2 10-4 10-6 10-8 10-10 10-12 10-14

• 7.0
• 3.5

0.0 3.5 7.0 Current [A] Voltage [V]

1000 °C 800 °C 450 °C

100 10-2 10-4 10-6 10-8 10-10 10-12 10-14

Slide 11

Results: Crystallographic Investigations: GI-XRD

10 20 30 40 50 60 70 80 90 Intensity [a.u.] 2 [°]

HfO2 3.1 mol% 4.8 mol% 7.1 mol% 8.5 mol % 11.4 mol%

10 20 30 40 50 60 70 80 90 d 2 [°]

cubic

10 20 30 40 50 60 70 80 90 d 2 [°]

monoclinic

d 

tetragonal

10 20 30 40 50 60 70 80 90 d 2 [°]

• rthorombic

80 85 90 Intensity [a.u.] 2 [°] HfO2 4.8 mol% 11.4 mol%

331c 420c 331o 133o 421o 133m

• 304m
• 241m
• 124m

313m

Compared to e.g. 30° to 40°: Unlikely to

• ccur from

sole superposition

• f m & t

 Transition phase seems plausible  Existen stence ce

• f
• f a

a transi nsitio tion phase

18.06.2012

• S. Mueller et al., “Incipient Ferroelectricity in Al-Doped HfO2 Thin Films”, Adv. Func. Mat. 22

22, 2412 (2012)

Slide 12

Immed ediate ate Applica icatio tion: n: Ferroelectric Field Effect Transistors (FeFET) Intel 45 nm node (2007): Introduction of HfO2 as Gate- Oxide Replacement  Stand ndard rd Materi erial l to to date!

“Homeopathic” Doping ng

Globalfoundries 28 nm node (2012): World‘s first st 28 28 nm nm Si:HfO HfO2 ferroele roelectric ctric field effe fect ct transistor nsistor (FeFET FET)

Source: J J. Müller et al., “Ferroelectricity in HfO2 Enables Nonvolatile Data Storage in 28 nm HKMG”, 2012 IEEE Symposia on VLSI Technology and Circuits, submitted for publication.

„0“

„0“

„1“

„1“

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• - -

• + -

Slide 13

Advantages and Applications

Ferr rroel elect ectric ric HfO2

CM CMOS- Co Compati atibil bility ity

Fe FeFE FET Memorie ies

Negat gativ ive Capac pacit itanc nce Devic ices (Log

• gic

ic)

FRAM Memorie ies

Non-Volat latil ility ity

Lead ad-Free ee Ferr rroele

• eletric

ic

Ease se of

• f

Pr Proce

• cessing

ssing

Stora

• rage

ge Clas ass Memor

• ry

Energy gy Effi ficient cient

ALD- capability bility

Scal alabi ability ty

ns ns- Switch tchin ing

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• - -

• + -

Slide 14

Summary Proce cessin ssing of

• f Al

Al:HfO

fO2 MIM-Capa Capacito citors rs (PMA A & PDA) 1 Observa ervati tion

• n of
• f Ferroe

roelectric ectric Phase se Transitio sitions 2

“AFE” (A)F )FE FE FE PE PE

Explan anati ation

• n in Terms

ms of

• f Inte

termed rmediate ate Phase se Pbc21 3 (Immed mediate ate ) ) Applicatio cations 4

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FeFET ET FRAM

Slide 15

Thank You!

and Thanks to the FeFET-Team at

&

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The work for this paper was supported within the scope of technology development by the EFRE fund of the European Community and by funding from the Free State of Saxony (Project HEIKO).

Slide 16

Backup

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Slide 17

Piezo-Response Even though crystallog. Origin of FE not 100% proven, behavior very FE FE- characte acteristic ristic:

• Piezo Resp.
• Imprint
• Retention
• Fatigue
• PUND
• SW-Speed
• Sub-Loops

FE FE- characteri racterist stic:

18.06.2012

Source: T.S.Böschke et al., „Phase transitions in ferroelectric silicon doped hafnium

• xide“, Appl. Phys. Lett. 99, 112904 (2011)

Source: T.S.Böschke et al., „Ferroelectricity in hafnium oxide thin films“, Appl. Phys. Lett. 99, 102903 (2011)