1. High Performance ALD HfO2-Al2O3 Laminate MIM
Capacitors for RF and Mixed Signal IC Applications
Hang Hu1, Shi-Jin Ding1, HF Lim1, Chunxiang Zhu1, M.F. Li1, 2, S.J.Kim1, XF Yu1, JH Chen1, YF Yong1, Byung Jin Cho1, D.S.H. Chan1, Subhash C Rustagi2, MB Yu2, CH Tung2, Anyan Du2, Doan My2, PD Foo2, Albert Chin3, Dim-Lee Kwong4
1SNDL, Dept. of ECE, National Univ. of Singapore, Singapore,
2Institute of Microelectronics, Singapore,
3Dept. of Electronics Eng., National Chiao Tung Univ., Taiwan
4Dept. of Electrical & Computer Eng., Univ. of Texas, Austin, TX 78712, USA
Silicon Nano Device Laboratory / Dept of ECE

2. Outline of Presentation
Motivation
Experiment
Results and Discussion
RF characterization
DC properties
Reliability and lifetime
High-κ MIM capacitors comparison
Conclusions

3. Voltage linearity (ppm/V2) Voltage linearity (ppm/V)
Motivation
Mixed signal MIM capacitor requirement
Year of Production
2003
2004
2005
2006
2007
2010
2013
2016
Analog capacitor
Density (fF/µm2) 3 4 7 10 15
Voltage linearity (ppm/V2)
100
Leakage (fA[pF•V]
RF bypass capacitor 8 9 11 12 17 20 23
Voltage linearity (ppm/V)
1000
The International Technology Roadmap for Semiconductors, 2002 Edition

4. Motivation
SiO2 and Si3N4 MIM capacitors usually provide low capacitance density of ~1 fF/μm2.
High-k dielectrics needs to be used for future MIM application according to ITRS roadmap.
HfO2 is a promising high-k material for MIM capacitor. However fast oxygen diffusion.
Al2O3 have the advantage of large band gap, low oxygen diffusivity, however only middle k value.

5. TEM photo of 13 nm laminate film
Experiment
4 μm SiO2 deposition on Si substrate for isolation
Bottom electrode deposition (Ta/TaN)
Transmission line formation
Dielectric deposition by atomic layer deposition (ALD)
Al2O3 (1nm)/HfO2 (5nm) laminate
Al2O3 as electrode contacting layers
13, 31, and 43 nm used in our work
TEM photo of 13 nm laminate film

6. Experiment Post deposition anneal (420oC) Contact hole etching
Top metal deposition (TaN/Al) and patterning
Final Device structure for characterization
MIM structure
Dummy device

7. Capacitor modeling in RF regime
I. RF capacitor model
Capacitor modeling in RF regime
Equivalent circuit diagram for MIM capacitor
modeling in RF regime

8. I. S-parameter simulation
13 nm
31 nm
43 nm
Measured and simulated S-parameters for laminate
MIM capacitors by IC-CAP using SPICE3 simulator.

9. I. High frequency response
High frequency response of laminate MIM
capacitors from 50 MHz to 20 GHz

10. I. Cap. versus frequency
The frequency dependence of capacitance density
of laminate capacitors (k ~19).

11. II. J-V characteristics
Typical J-V characteristics of laminate MIM capacitors

12. II. J-V characteristics
Leakage obtained at different temperatures for 13
nm MIM capacitor (normalized to JRT: leakage
measured at room temperature)

13. II. Conduction mechanism
Conduction mechanisms of 13 nm laminate MIM
capacitor, showing Pool-Frankel conduction at
high field.

14. II. CV characteristics
Quadratic (α) and linear (β) VCCs of laminate MIM
capacitors with thicknesses of 13, 31 and 43 nm

15. II. CV characteristics Thickness dependence of quadratic VCC (α) for
laminate MIM capacitors. The implication is
significant for the scaling of the high-k dielectrics.

16. II. CV characteristics Frequency dependence of quadratic VCC α for
laminate MIM capacitors

17. II. CV characteristics Quadratic VCC  as a function of stress time.
The inset shows time dependence of linear VCC .

18. II. CV characteristics Time dependence on VCCs and leakage, under
stress condition. The recovery of leakage and VCCs
may further prolong lifetime under AC condition.

19. II. TCC properties TCC values for laminate MIM capacitors
with three different thicknesses

20. III. Constant voltage stress
Stress time dependence of leakage for a fresh
device up to 2000s. The device was re-stressed and
re-measured after interrupting stress for 10 hours.

21. III. Breakdown characteristics
Breakdown and leakage characteristics of 13 nm
laminate MIM capacitors as a function of stress time.

22. III. Lifetime projection
Life time projection of 13 nm laminate capacitor, using
50% failure time criteria, the extrapolated voltage for
10 years lifetime is 3.3 V.

23. IV. High-κ MIM cap. comparison
Reference
[1]
[2]
[3]
[4]
[5]
This work
Dielectric
HfO2 (ALD)
Ta2O5
AlTaOx (PVD)
Ta2O5 (CVD)
Tb doped HfO2 (PVD)
Hf/Al laminate (ALD)
Capacitance density (fF/µm2) 13
9.2 10 9
13.3
12.8
Leakage (A/cm2) —
VCC
607 ppm/V
853 ppm/V2
2060 ppm/V 3580 ppm/V2
2818 ppm/V2
2050 ppm/V
475 ppm/V2
332 ppm/V
2667 ppm/V2
211 ppm/V
1990 ppm/V2
TCC (ppm/oC)
~200
255
123
198
Laminate capacitor is among one of the best for RF capacitor application.
[1]. XF Yu et al. EDL. Vol. 24, 2003.
[2]. Tsuyoshi. I et al. IEDM 2002, p.940.
[3]. C. H. Huang, et al. MTT-S
[4]. Y. L. Tu. et al VLSI symp. 2003, p.79.
[5]. S.J. Kim et al. VLSI symp. 2003, p.77.

24. Conclusions High performance HfO2/Al2O3 laminate MIM capacitors
have been demonstrated for the first time.
The ALD laminate MIM capacitors exhibit high C
density, superior dielectric stability up to 20 GHz,
low leakage current, and promising reliability.
For 13 nm laminate MIM capacitor C density ~12.8 fF/μm2 up to 20 GHz
 ~ 211 ppm/V, Leakage ~ 7.45 nA/cm2 at 2 V Meets all requirements for RF bypass capacitor

25. Acknowledgment
This work was supported by Institute of Microelectronics (Singapore) under Grant R and the National University of Singapore under Grant R