Advantages of Ion Cluster Implantation In CMOS Manufacturing€¦ · In CMOS Manufacturing Advantages of Ion Cluster Implantation In CMOS Manufacturing Thomas Horsky Junction Technology

© 2006 SemEquip, Inc. Confidential and Proprietary

Advantages of Ion Cluster Implantation

In CMOS Manufacturing

Advantages of Ion Cluster Implantation

In CMOS Manufacturing

Thomas Horsky

Junction Technology Group

Semicon West, July 19 2007

Junction Technology Group Presentation at SemiCon West , San Francisco, CA, July 19, 2007 2

Outline

Cluster concept

Types of ion clusters

Productivity enhancement

Activation

Junction leakage

Defects

Amorphization; crystal regrowth

Carbon for diffusion control

Stress engineering with SiC for NMOS channel mobility enhancement

Channeling & implant energy control

Summary


Cluster Concept—Productivity Advantage

18 dopant atoms per cluster

Increases effective dose rate by 18X

Extract and transport at 20X higher energy

Reduces net current to wafer by 18X (reduced

charging)

Deceleration is not required, eliminating energy

contamination

Enables cost-effective low energy, high dose

Implants

Low angular divergence low-energy beams at wafer

+ 20 keV B18Hx+

1 mA

+

18 mA

1 keV B+

Is process equivalent to


Process Advantages of B18H22 ImplantationAdvanced Logic & Memory

Higher ThroughputProduction-worthy throughput for doses up to 3E16cm-2; enabling for dual gate poly doping, contact plug, deep S/D

Up to 50mA B even at low (1-4 keV)

>100WPH at 200eV PMOS SDE (32nm design rule)

No Energy ContaminationAll implants are in drift mode

Enables abrupt junctions

Reduced risk of Vth shifts due to gate punch-through

Simplified Process FlowNo Ge or Si pre-amorphization needed due to self-amorphization property of cluster

Shallower as-implanted profiles→ conventional spike anneals can be used for USJ

Improved Device CharacteristicsNo implanted F, which can promote through-gate dopant diffusion

Conventional beam line means tight dose & energy control

Low angular divergence at wafer leads to abrupt junctions, reduces Vth variation due to shadowing

Improved dopant activation at low thermal budget due to self-amorphization

Lower leakage because there are no end-of-range defects (perfect re-crystallization is possible)

Much reduced angular divergence and improved spatial uniformity for MC and serial HC compared to low-energy monomer beams

Enables high tilt, under-the-gate implants (e.g., Halo)


Cluster Species Available with ClusterIon® Source

B18H22, B10H14

C16H10, C7H7

As4, P4

Arsenic Spectrum

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 50 100 150 200 250 300 350

Mass (AMU)

As+ C

urre

nt (m

A)

As4+

As2+

0200400600800

100012001400

0 25 50 75 100 125 150 175 200 225 250Mass (AMU)

Fara

day

Cur

rent

(uA

)B18H22 Spectrum

B18Hx+


L. Rubin et al., IWJT2007 (Axcelis)HC Drift Mode Performance of Optima Implanter


What implants can be better done with Clusters?

B18H22 , P4 and As4 can be used for USJ n+ and p+:

Source/Drain Extension

Deep Source/Drain

Poly Gate

Halo

Source Drain

Poly Gate

Ext + Pre–amorphizing

Well

Ext

Halo

Vt ADJ

Punch Through

Planar CMOS Structure

SDE: 100 eV—2 keV, 1E14—1E15

S/D: 1 keV—8 keV, 1E15—7E15

Halo: 3 keV—10 keV, 1E13—1E14

Poly: 1.5 keV—4 keV, 7E15—3E16


Scaling Challenges

Precision dopant placement is critical for source drain extension implants (angle control)

HALO implants requiring higher dose, lower energy to improve electrical performance in the channel

Repeatable implant profiles require ZERO energy contamination

Advanced Logic 65nm & 45nm DRAM Development 90nm & 70nm

Poly implants requiring lower energies and higher doses; < 5keV, ≥ 1.0E16

Zero tolerance for energy contamination in gate oxide

Slide Courtesy of Axcelis Technologies


L. Rubin et al., IWJT2007 (Axcelis)


Comparison of PLAD & Beamline DopingJ. Borland et al, IWJT2007


Akira Mineji et al., IWJT2007 (NEC, NIC, JOB)750 eV, 1E15 B SDE


Borland et al., IWJT2007


Summary of RsL and PLi Metrology ResultsJohn Borland et al., IWJT2007 (Selete, Nanometrics)

(SPE at 650C)


Junction Leakage Current

Non-PAI B18 has > 2 orders of magnitude lower junction leakage current using diffusion-less laser and SPE anneals

This is consistent with low damage junction in PL results

1.00E-08

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

B B+PAI BF2 BF2 + PAI B18 B18 + PAI

RsL

Lea

kage

Cur

rent

(A/c

m2)

Spike 1000Spike 1080Flash 1300Laser 1300SPE 650

After John Borland et al., IWJT2006, May 15—16, 2006, Shanghai, China, pp. 4—9.


Silicon Crystal Lattice Damage(JOB & NEC, IWJT2006 & SST2006)

0

10

20

30

40

50

60

70

80

90

100

B B+PAI BF2 BF2 + PAI B18 B18 + PAI

PL (a

rbitr

ary

units

)as -im plant(c ontrol)S pike 1000S pike 1080Flas h 1300Las er 1300S PE 650

B18 has lowest Junction damage with various annealing techniques


X-TEM of Self Amorphizing with B18H22(GIST IWJT2006)

as-implanted 250eV 1E15 B equiv. after excimer laser anneal

Flat surface

(a) Uniform Si interface at amorphous layer;

(b) Post-anneal Si re-crystallization without defects


Amorphous Layers Created by 1E15 implants of B18Hx

+ and C16Hx+ Ions

(a): X-TEM of a 1e15, 500eV per boron B18Hx (b): X-TEM of a 1e15, 3keV per carbon C16Hx+

implant yielding a 6.2nm amorphous layer implant yielding a 14nm amorphous layer

(a) (b)

Surface

Surface


5nm

X-TEM of as-implanted(Fujitsu IWJT2006)

B10Hx B18Hx B w/ Ge-PAI

Amorphous-silicon crystal interface of B10 and B18 cases are smooth while Ge-PAI indicate rough interface and small defects are observed.

(GIST, IWJT2006)


BF2 EOR Damage - TEM

EOR damage

Laser anneal SPE anneal


Plan View TEM’s of B18H22-implanted samples after various anneals

No EOR Defects Visible

(a) 650C SPE anneal (b) 720C SPE anneal 1075C spike anneal

Klaus Funk, Einladung zum RTP- & Ionenimplantations-Nutzergruppen-Treffen,Villach, Austria, September 25-26, 2006.


X-TEM of 950C, 5s Annealed Samples after B18Hx+

and C16Hx+ Co-Implants showing no EOR Defects

20 nm scale 5 nm scale

X-TEM images after 1e15 cm-2, 3keV C16Hx+ + 0.5keV B18Hx

+ implants followed by a 5s, 950C spike anneal.


B18H22 X-TEM with various anneals(JOB & NEC, IWJT2006 & SST2006)

(a)

(b)(c)

(d)

(a) B18H22 6.2nm self-amorphous layer (as-implanted)

(b) SPE with no EOR damage

(c) Laser with no EOR damage

(d) Flash with no EOR damage


SIMS Boron Depth profile

1E+18

1E+19

1E+20

1E+21

1E+22

0 10 20 30 40 50

nm

Ato

m/c

m3

B:500eVB:500eV Ge-PAIB18H22:10keVB18H22:10keV Ge-PAI

B18H22 with 6.2nm of Self-Amorphization

Boron 500eV 1E15/cm2 equivalent (PAI: Ge 5KeV 5E14/cm2) Xj @1E18

B 25.2nm

B18 19.1nm

B + PAI 17.8nm

B18 + PAI 16.1nm

B18 Self-Amorphization helps to make Shallower Junction and Eliminate the need of Ge-PAI


Cabron Cluster Implantation for B Diffusion Control(SemEquip IIT2006)

Reduction of boron diffusion during anneal

Improvement of junction abruptness

Increase in boron solubility in the active junction volume

1E+15

1E+16

1E+17

1E+18

1E+19

1E+20

1E+21

1E+22

0 10 20 30 40 50 60Depth (nm)

Con

cent

ratio

n (a

tom

s/cc

)

as-implanted

1050 C _ no Carbon

1050C _ 3keV Carbon


as-implanted SIMS Profiles: C16 vs. Ge PAI

Abrupt junction with C16 with co-implants

B18 with co-implant BF2 with co-implant

1E+15

1E+16

1E+17

1E+18

1E+19

1E+20

1E+21

1E+22

0 200 400 600 800DEPTH (Å)

B C

ON

CEN

TRA

TIO

N (a

tom

s/cc

)

B18

B18 + C16

B18 + Ge

B18 + C16 + Ge

B

as-implanted samples

1E+15

1E+16

1E+17

1E+18

1E+19

1E+20

1E+21

1E+22

0 200 400 600 800DEPTH (Å)

B C

ON

CEN

TRA

TIO

N (a

tom

s/cc

)

BF2

BF2 + C16

BF2 + Ge

BF2 + C16 + Ge

B

as-implanted samples


B18 – 500eV, 1e15 (FLASH ANNEAL)SE + J. Gelpey, Mattson

Sheet Rho

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Spike 1000C

Spike 1025C Spike 1050C Ti_750C_Tpk_1050C

Ti_750C_Tpk_1250C

Ti_900C_Tpk_1050C

Ti_900C_Tpk_1250C

Ti_900C_Tpk_1300C

Ti_900C_Tpk_1350C

Ti_1000C_Tpk_1250C

Ti_1000C_Tpk_1300C

Implant Species

Shee

t Rho

(Ohm

/Sq)

B18


Flash anneal : Rs Results(SE + J. Gelpey, Mattson)

Sheet Rho

0

400

800

1200

1600

2000

2400

2800

3200

3600

4000

B18 B18 +C16

B18 + Ge B18 +C16 + Ge

BF2 BF2 +C16

BF2 + Ge BF2 +C16 + Ge

Implant Species

Shee

t Rho

(Ohm

/Sq)

f_Spike_900C

flash_Ti_900C_Tpk_1250C




f_Spike_1050C

Lower Rs is observed for f-spike 1050C and flash-Ti_900C_Tpk_1350C.


Rs. Xj Product : measure of active carrier concentration (SE + J. Gelpey, Mattson)

Rs. Xj product (inverse of active carrier concentration) is lowest for B18 implant indicating a higher active carrier concentration in the active junction area.

Rs. Xj

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

B18 B18 +C16

B18 + Ge B18 +C16 + Ge

BF2 BF2 +C16

BF2 + Ge BF2 +C16 + Ge

Implant Species

Rs.

Xj

(Ohm

/Sq.

nm

)

f_Spike_900C



f_Spike_1050C


5nm

X-TEM C16 (3keV) + B18 (0.5keV) @1e15 atoms/cm2

950oC , 5 sec – annealed NO EOR DAMAGE

20nm scale 5nm scale

No EOR damage is seen with TEM for 950oC 5 sec anneal

SurfaceSurface


5nm

X-TEM C16 (3keV) + B18 (0.5keV) @1e15 atoms/cm2

Various Anneal Temperatures : NO EOR DAMAGE

950oC

No EOR damage is seen with TEM

Surface

Surface

1025oC 1075oC

Surface


Carbon Implant + SPER for e-Si:C in NFETsYaocheng Liu et al., IBM (VLSI 2007)


ClusterCarbon for Stress: Raman – C16H16 @3e15

Raman Spectra - C16H16

0

100

200

300

400

500

600

700

800

508 510 512 514 516 518 520 522 524 526 528 530

Wavenumber (cm-1)

Inte

nsity

(a.u

)

C16_6k_3e15_650C_A6

C16_6k_3e15_750C_A10-2

C16_6k_3e15_850C_A14-1

Reference_Si (scaled)

7.01 Gdynes/cm2

6.93 Gdynes/cm2

6.65 Gdynes/cm2

C16@3e15 dose, the avg. stress values for the temp. range more or less remain the same.


ClusterCarbon for Stress: Raman – C7H7 @3e15

Raman Spectra - C7H7

0

200

400

600

800

508 510 512 514 516 518 520 522 524 526 528 530

Wavenumber (cm-1)

Inte

nsity

(a.u

)

C7_6k_3e15_650C_B5-1

C7_6k_3e15_750C_B8-2

C7_6k_3e15_850C_B11-2

Reference_Si(scaled)

5.96 Gdynes/cm2

7.56 Gdynes/cm2

7.08 Gdynes/cm2

@3e15 dose, the avg. stress values for the temp. range lie within ± 15% of each other


ClusterCarbon: Stress Data

Raman Scattering (C16H10 & C7H7) (UV Laser 363.8nm)

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

6k_1

e15_

650C

6k_3

e15_

650C

6k_5

e15_

650C

6k_1

e15_

750C

6k_3

e15_

750C

6k_5

e15_

750C

6k_1

e15_

850C

6k_3

e15_

850C

6k_5

e15_

850C

6k_1

e15_

650C

6k_3

e15_

650C

6k_5

e15_

650C

6k_1

e15_

750C

6k_3

e15_

750C

6k_5

e15_

750C

6k_1

e15_

850C

6k_3

e15_

850C

6k_5

e15_

850C

Implant & Anneal

Res

idua

l Str

ess

(GD

yne/

cm2)

C16H10 - 6keV C7H7 - 6keV


SummaryDue to collective effects, amorphization during cluster implantation yields powerful process advantages using low thermal budget anneals:

More complete crystal regrowth lowers defect density

Lower defect density reduces junction leakage

Active carrier concentration is increased

Channeling reduction results in shallower, more abrupt junctions without Ge PAI

3-5X increase in wafer throughput for high dose, low energy processes without risk of energy contamination

Carbon clusters are effective at creating e-Si:C with increased activation of substitutional carbon during SPER, resulting in higher tensile stress than achievable with monomer carbon implants


Acknowledgements

SemEquip: Dale Jacobson, Wade Krull, Bob Milgate, Karuppanan Sekar, Jeff Buda, Brian Haslam

Mattson: Jeff Gelpey

Axcelis: Mike Ameen, Mark Harris

Documents

Advantages of Ion Cluster Implantation In CMOS Manufacturing€¦ · In CMOS Manufacturing Advantages of Ion Cluster Implantation In CMOS Manufacturing Thomas Horsky Junction Technology