Dependence of the thickness and composition of the HfO 2 /Si interface layer on annealing

(1)

CINVESTAV

P.G. Mani-González and A. Herrera-Gomez

[email protected]

Dependence of the thickness and composition of the

HfO

₂

/Si interface layer on annealing

CINVESTAV-UNIDAD QUERETARO

(2)

background

• Introduction

– ALD – DC Sputtering – XPS • ARXPS

• Growth of HfO

₂

films by ALD

– Caracterization by XPS

• Growth of TaN films by DC sputtering

• Annealing of Si/HfO

₂

/TaN

– Removed TaN

– Charaterization by XPS

• Conclusions

(3)

CINVESTAV

Introduction

•

High thermal stability and high dielectric

constant.

•

Get the composition and thickness of the HfO

₂

/Si

(4)

ALD (atomic layer deposition)

Si/

HfO

₂ Si (001) HfO2 RCA

Si (100)

M1 M2

(5)

CINVESTAV

DC sputtering

Si/

HfO

₂

/

TaN

Si (001) TaN HfO2 P_B= 6.4X10-6 _torr Ar N₂

(6)

XPS

X-ray source

Al K no-monochromatic

h

= 1486.6 eV

K L M electrons X ray

E

_K

=

h

-

E

_B

Mg K no-monochromatic

h

= 1253.6 eV

(7)

CINVESTAV 1385 1390 1395 1400 1405 1410 1415 1420 1425 0 500 1000 1500 2000 2500 3000 In te nsi ty Kinetic Energy Au 4f_7/2 1385 1390 1395 1400 1405 1410 1415 1420 1425 0 500 1000 1500 2000 2500 3000 In te nsi ty Kinetic Energy 1385 1390 1395 1400 1405 1410 1415 1420 1425 0 500 1000 1500 2000 2500 3000 In te nsi ty Kinetic Energy 1385 1390 1395 1400 1405 1410 1415 1420 1425 0 500 1000 1500 2000 2500 3000 In te nsi ty Kinetic Energy 1385 1390 1395 1400 1405 1410 1415 1420 1425 0 500 1000 1500 2000 2500 3000 In te nsi ty Kinetic Energy 1385 1390 1395 1400 1405 1410 1415 1420 1425 0 500 1000 1500 2000 2500 3000 In te nsi ty Kinetic Energy 1385 1390 1395 1400 1405 1410 1415 1420 1425 0 500 1000 1500 2000 2500 3000 In te nsi ty Kinetic Energy 1385 1390 1395 1400 1405 1410 1415 1420 1425 0 500 1000 1500 2000 2500 3000 In te nsi ty Kinetic Energy 1385 1390 1395 1400 1405 1410 1415 1420 1425 0 500 1000 1500 2000 2500 3000 In te nsi ty Kinetic Energy sample X-Ray Source Au 4f_5/2

ARXPS

concentric hemiespheric analyzer

Si(001) Au 15 to 90 X PS s ignal (a. u. ) Kinetic Energy eV

(8)

background

• Introduction

• Growth of HfO

₂

films by ALD

• Growth of TaN films by DC sputtering

₂

/TaN

– Removed TaN

• Conclusions

(9)

CINVESTAV

Growth of HfO

2

in silicon wafer by ALD

TDMA-Hf (Tetrakis dimetilamino-Hf)

H

₂

O (DI)

Growth condition

P_i= 2.039x10-1 _torr

275 °C on the substrate 200 °C on the wall

(10)

ARXPS in sample with 30 cycles

Si 2p Hf 4f O 1s C 1s Binding energy In te n sity

(11)

CINVESTAV

Growth of HfO

₂

/Si varying the number cycles

Hf 4f Si 2p O 1s Ciclos 25 20 15 10 5 Ciclos 5 10 15 20 25 Ciclos 25 20 15 10 5 Binding energy In te n sity Binding energy In te nsity Binding energy In te n sity

(12)

background

• Introduction

• Growth of HfO

₂

films by ALD

₂

/TaN

– Removed TaN

• Conclusions

(13)

CINVESTAV

TaN film grown by DC sputtering

N

₂

Ta

P_T= 2.6X10-4 _torr t= 4 min P= 100 W Thickness= 1000 Å

(14)

Characterization XPS in TaN films

Ta 4f Ta 4d N 2.5% N 5% N 10% N 1s Binding energy In te n sity

(15)

CINVESTAV

Comparing TaN films grown by laser ablation and DC

Sputtering

Ta 4f Laser ablation * 10 5 2.5

N flow (%) Ar flow (%) N (cm3) Ar (cm3) Thickness (Å) Resistivity (Ω cm)

2.5 97.5 0.6 24.4 1464 1.596E+02 5 95 1.3 23.7 1090 7.358E-02 10 90 2.5 22.5 1087 6.36E-04 1000 3.73E-04 Laser A. Binding energy In te n sity

(16)

ARXPS in TaN films

N 1s O 1s Ta 4f 0° 15° 30° 45° 60° 75° Binding Energy In te n sity In te n sity Binding Energy In te n sity Ta associated in TaN Ta associated in Ta₂O₅

(17)

CINVESTAV

Characterization XRD for TaN films

(111)

(200)

(220)

2θ In te n sity Laser ablation DC Sputtering

(18)

background

• Introduction

• Growth of HfO

₂

films by ALD

₂

/TaN

– Removed TaN

• Conclusions

(19)

CINVESTAV

Thermal annealing and removed TaN for Si/HfO

₂

/TaN

N

₂

T=700-1000 °C

10 seg

T

₂ Aire Aire

N

₂

Removed TaN

NH

₄

OH:H

₂

O:H

₂

O

₂

10:1:1 to 85 °C

(20)

XPS after removed TaN film

O 1s 700 °C 800 °C 900 °C 1000 °C Si 2p Hf 4f O associated in HfO2 O associated in SiO₂ 530.52 eV 531.92 eV 101.93 eV 399.17 eV 405.14 eV N 1s Ta 4f is not NO₂* Binding Energy In te n sity

(21)

CINVESTAV

Thickness calculation

sen exp sen exp sen exp 1 1 sen exp 1 sen exp 1 , , 2 2 2 Hf HfO SiO SiO Si Si C C C C Si Si C C Si C d d a a d s s I I r r S above layers i , cos exp cos exp 1 cos exp 1 , i S i S S S S S S S d a d s A X I r r

Equations (model) and parameters employed in the calculations

KE

(22)

Parameters

SiO2 2.1 nm 4.8 nm Si (100) substrate C HfO₂ 0.25 nm

effective attenuation lengths cross section assymetry KE Si SiO2 HfO2 Carbon Si 2p 0.11 1.1 1153.95 29.2 35.2 17.2 33.4 Hf 4f 0.118 1.02 1236.36 36.9 18 35 N 1s 0.024 2 854.511 28.4 13.9 27.2 O 1s 0.04 2 722.75 25.5 12.5 24.4 C 1s 0.013 2 967.76 31 15.1 29.5 Thickness 21.0038668 47.9606174 2.59638606

(23)

CINVESTAV

Conclusions

•The annealing present a different phase of SiO2 and HfO2 moved the binding energy.

•increasing the cycles number, the signal of O assotiated to HfO2 increase.

•TaN is not present after of removed in the samples annealing •With annealing the N is going to entrance to lattice of the HfO2

•N 1s present a peak of correspond to NO2 is possible to introduce of HfON, SiON or both of them.

(24)

Conclusiones

•Increase the SiO2 peak with annealing

•The suboxide in the Si 2p to continue increase with the temperature. • We have a uniform and control in the grown of HfO2 films but is formed a SiO2 in the interface of HfO₂/Si.

• is possible to see the contribution of TaO and TaN respect the angle resolution the Ta₂O₅ is on the surface and N of the TaN is depth.