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

Transcription

1 Dependence of the thickness and composition of the HfO 2 /Si interface layer on annealing CINVESTAV-UNIDAD QUERETARO P.G. Mani-González and A. Herrera-Gomez gmani@qro.cinvestav.mx CINVESTAV 1

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 Caracterization by XPS Annealing of Si/HfO 2 /TaN Removed TaN Charaterization by XPS Conclusions CINVESTAV 2

3 Introduction High thermal stability and high dielectric constant. Get the composition and thickness of the HfO 2 /Si interface. CINVESTAV 3

4 ALD (atomic layer deposition) Si/HfO 2 HfO 2 Si (001) Si (100) RCA ALD M 1 M 2 M 3 Pulse (seg) Drain (seg) H 2 O M 4 TDMA-Hf M 5 CINVESTAV 4

5 DC sputtering Si/HfO 2 /TaN TaN HfO 2 Ar N 2 Si (001) P B = 6.4X10-6 torr CINVESTAV 5

6 XPS X-ray source X ray Al K no-monochromatic M h = ev Mg K no-monochromatic h = ev electrons L K E K =h -E B CINVESTAV 6

7 Intensity Intensity Intensity Intensity XPS signal (a.u.) ARXPS concentric hemiespheric analyzer 3000 X-Ray Source 2500 Au 4f 7/ sample Au 4f 5/2 15 to 90 Au Si(001) Kinetic Energy Energy ev CINVESTAV 7

8 background Introduction ALD DC Sputtering XPS ARXPS Growth of HfO 2 films by ALD Caracterization by XPS Growth of TaN films by DC sputtering Caracterization by XPS Annealing of Si/HfO 2 /TaN Removed TaN Charaterization by XPS Conclusions CINVESTAV 8

9 Growth of HfO 2 in silicon wafer by ALD H 2 O (DI) TDMA-Hf (Tetrakis dimetilamino-hf) Growth condition P i = 2.039x10-1 torr 275 C on the substrate 200 C on the wall 70 C on the cylinder TDMA-Hf CINVESTAV 9

10 Intensity ARXPS in sample with 30 cycles Hf 4f C 1s Binding energy Si 2p O 1s CINVESTAV 10

11 Intensity Intensity Intensity Growth of HfO 2 /Si varying the number cycles Ciclos Si 2p Ciclos Hf 4f Binding energy Binding energy Ciclos O 1s Binding energy CINVESTAV 11

12 background Introduction ALD DC Sputtering XPS ARXPS Growth of HfO 2 films by ALD Caracterization by XPS Growth of TaN films by DC sputtering Caracterization by XPS Annealing of Si/HfO 2 /TaN Removed TaN Charaterization by XPS Conclusions CINVESTAV 12

13 TaN film grown by DC sputtering N 2 Ta P T = 2.6X10-4 torr t= 4 min P= 100 W Thickness= 1000 Å CINVESTAV 13

14 Intensity Characterization XPS in TaN films N 1s Binding energy Ta 4d N 10% Ta 4f N 5% N 2.5% CINVESTAV 14

15 Comparing TaN films grown by laser ablation and DC Sputtering Intensity Ta 4f Laser ablation * Binding energy N flow (%) Ar flow (%) N (cm 3 ) Ar (cm 3 ) Thickness (Å) Resistivity (Ω cm) E E E E-04 Laser A. * Dr. Wencel de la Cruz (CNyN) CINVESTAV 15

16 Intensity Intensity Intensity ARXPS in TaN films Ta associated in Ta 2 O 5 Ta 4f Ta associated in 0 TaN N 1s Binding Energy O 1s Binding Energy Binding Energy CINVESTAV 16

17 Intensity Characterization XRD for TaN films (111) Laser ablation DC Sputtering (220) (200) 2θ CINVESTAV 17

18 background Introduction ALD DC Sputtering XPS ARXPS Growth of HfO 2 films by ALD Caracterization by XPS Growth of TaN films by DC sputtering Caracterization by XPS Annealing of Si/HfO 2 /TaN Removed TaN Charaterization by XPS Conclusions CINVESTAV 18

19 Thermal annealing and removed TaN for Si/HfO 2 /TaN N 2 Aire Aire N 2 T= C 10 seg T 2 Removed TaN NH 4 OH:H 2 O:H 2 O 2 10:1:1 to 85 C CINVESTAV 19

20 Intensity O associated in SiO 2 XPS after removed TaN film O 1s O associated in HfO 2 N 1s ev NO 2 * ev 1000 C 900 C 800 C 700 C ev ev Binding Energy Si 2p Ta 4f is not Hf 4f ev 99.4 ev ev ev * V.B. Wiertz, P. Bertrand, Identification of the n-containing functionalities introduced at the surface of ammonia plasma treated carbon fibres by combined TOF SIMS and XPS, Unité de Physico-Chimie et de Phys. Des Mat., Univ. Louvain 1348 Editor, Louvain. CINVESTAV 20

21 Thickness calculation Equations (model) and parameters employed in the calculations layers d 1 exp S above S S cos d I, exp i S r X r A S ss a, i cos 1 exp S i S cos S A 1 ~ (not exactly, but close) KE I I C Si, r, r C Si s s C Si 1 exp 1 Si asi sen 1 1 exp exp exp C C d SiO2 dc sen ac sen SiO2 sen exp d Hf HfO2 sen CINVESTAV 21

22 Parameters effective attenuation lengths cross section assymetry KE Si SiO2 HfO2 Carbon Si 2p Hf 4f N 1s O 1s C 1s Thickness The thicknesses were varied to reproduce the anions (Si, Hf and C) data C HfO 2 SiO nm 4.8 nm 2.1 nm Si (100) substrate CINVESTAV 22

23 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. The thickness was calculated with the equation CINVESTAV 23

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 HfO 2 /Si. is possible to see the contribution of TaO and TaN respect the angle resolution the Ta 2 O 5 is on the surface and N of the TaN is depth. CINVESTAV 24