High Performance Ir/TiPrO/TaN MIM Capacitors for Analog ICs Application

High Performance Ir/TiPrO/TaN MIM Capacitors for Analog ICs Application

C. C. Huanga*, C. H. Chengb, Albert China, Senior Member, IEEE, and C. P. Choub

a

Dept. of Electronics Eng., National Chiao-Tung Univ., Hsinchu, Taiwan

b

Dept. of Mechanical Eng., National Chiao-Tung Univ., Hsinchu, Taiwan In this paper, we demonstrate high quality material TiPrO and high density TixPr1-xO (x~0.67) metal-insulator-metal (MIM) capacitors

using high work function (~5.3 eV) Ir top electrode. Very low

leakage current of 7u10-9 A/cm2 at -1 V and high 16 fF/Pm2

capacitance density are achieved for 400 oC anneal TiPrO, which

also meets the ITRS goals (at year 2018) of 10 fF/Pm2 density and

/( ) 7 fA/(pF )

J C V˜  ˜V . Furthermore, the improved high 20

fF/Pm2 capacitance density TiPrO MIM is obtained at higher

annealing temperature, wherelow leakage current 1.2u10-7 A/cm2

is measured at -1 V. These good performances indicate TiPrO MIM is suitable for analog/RF ICs Applications.

Introduction

The technology evolution for Metal-Insulator-Metal (MIM) capacitors (1)-(16) requires higher capacitance density with low leakage current at evaluating temperature (17). Besides, the MIM capacitors are also used for Analog/RF ICs and DRAM technology. Low voltage- or temperature-dependence of capacitance (VCC or TCC) is also needed for the multi-functional System-on-Chip (SoC) applications. Since the capacitance density equals HN/tN, the only method for higher density, without increasing unwanted leakage

current by decreasing dielectric thickness (tN), is to use higher dielectric constant

dielectric (N) materials. Thus, the MIM capacitors are continuously integrated with higher N dielectrics from Al2O3 (N=10) (3), HfO2-Al2O3 (N~15) (9), ZrO2, TiTaO (13), TiHfO

(15) and TiNiO (N~36) (16). One major drawback for higher-N MIM device is the large

leakage current due to low conduction band offset ('EC) at evaluated temperature that

leaks out the stored charge in capacitor (Q=C˜V). However, increasing dielectric constant

(N) usually leads to decreasing of 'EC with respect to the electrode. This is also the

challenge of flash memory but unavoidable during IC operation due to large circuit density and high DC power dissipation due to leakage current. The possible solution is using high bandgap (EG) dielectric to form the laminate (9) or multi-layer structure (10), but the overall N value and voltage coefficient of capacitance (VCC) are largely degraded.

Pr2O3 is one of attractive rare earth metal oxides with many merits such as large

conduction band offset ('EC~ 1 eV) (18), moderate dielectric constant (N~15) and large

bandgap (EG ~4 eV) (18). Furthermore, significantly larger Gibbs free energy of Pr2O3

(+106 kcal/mol) (19)-(21) in contact with silicon than that of TiO2 (+7.5 kcal/mol),

Ta2O5 (-52 kcal/mol), HfO2 (+47 kcal/mol) and NiO (-51.4 kcal/mol) can avoid

metal/oxide inter-diffusion or chemical reaction caused by oxygen exchange, which not only reduce the interfacial layer between dielectric layer and bottom electrode but also performs excellent thermal stability. Combining above advantages of high-N Pr2O3 with

the high dielectric constant of TiO2 (~50), mixed TiPrO dielectric overcomes the issue of

In this paper, we report Ir/TiPrO/TaN capacitors with capacitance density of 16

fF/Pm2 and further improved capacitance density of 20 fF/Pm2 using higher annealing

temperature. High-k values 26-32 were obtained in this work by using mixed TixPr

1-xO(x~0.67). By using high-NTiPrO with the ratio of Ti to Pr 2:1 and high work function

electrode Ir, we can achieve high capacitance density of 16-20 fF/Pm2, and low leakage

current of 7u10-9 A/cm2 to 1.2u10-7 A/cm2 at 25 oC at-1 V, small quadratic VCC (D) of

1720~2174 ppm/V2, and small TCC of 532~758 ppm/oC. The lower leakage shows

improved quadratic VCC (D) and TCC, which are important for analog/RF functions. It

would be important to note that the device shows large orders of magnitude lower

thermal leakage at 25 oC and 125 oC at -1V than our previous work on TiTaO (13) and

TiNiO (16), at comparable capacitance density. Such good device integrity is due to the mixed high-N TiPrO (N~26-32) with larger bandgap (EG~4 eV), larger high-N/Si

conduction band offset ('EC~1 eV) and larger Gibbs free energy (+106 kcal/mol) of

Pr2O3.

Experimental Procedure

After depositing 2 Pm SiO2 on a Si wafer, the lower capacitor electrode was formed

using PVD-deposited TaN/Ta bi-layers. The Ta was used to reduce the series resistance and the TaN served as a barrier layer between the high-N TiPrO and the Ta electrode. The

TaN was treated by NH3 plasma nitridation at 100W to improve the bottom interface. The

TaN layer with NH3 surface nitridation (22)-(23) can improve electrode stability and

prevent CET (capacitance equivalent thickness)degradation by forming interfacial TaON

during post-deposition anneal (PDA). Then 14 nm thick TixPr1-xO (x~0.67) dielectric

layer were deposited on the TaN/Ta electrode by PVD respectively followed by 400 oC

and 430 oC oxidation and annealing step to reduce the leakage current. Finally, Ir was

deposited and patterned to form the top capacitor electrode. The fabricated devices were characterized by C-V and J-V measurements using an HP4155B semiconductor parameter analyzer and an HP4284A precision LCR meter.

Results and Discussion

Fig.1 shows the C±V characteristics of Ir/TiPrO/TaN capacitors, which were

processed differently. The capacitance density increased from 16 to 20 fF/Pm2 with

increasing O2 PDA temperature from 400 oC to 430 oC.In Fig. 2a and 2b, we perform the J±V characteristics of the TiPrO MIM capacitors with capacitance density of 16 fF/Pm2

and 20 fF/Pm2 respectively, measured at 25 and 125 °C. The good J-V and C-V

characteristics are obtained with the use of high work function top electrode Ir (~5.27 eV)

and nitrogen plasma (N+) treatment on bottom electrode TaN. The nitrogen plasma (N+)

treatment reduces the interfacial layer growing between the bottom electrode TaN and TiPrO layer during oxygen annealing (22)-(23). It is very important to note that the

TiPrO MIM with capacitance density of 16 fF/Pm2 achieves the ITRS goals (at year

2018) (17) of 10 fF/Pm2 density and J/(C V˜ )7 fA/(pF˜V). This excellent result indicates TiPrO is a potential material candidate for future electrical device application.

To further evaluate the device performance, Fig. 3a and 3b show the temperature-dependent J-V characteristics of TiPrO MIM capacitors at capacitance density of 16 and

temperature; however, the high temperature operation is unavoidable for modern high performance IC due to the increasing power consumption. In addition, the unwanted interfacial layer between bottom electrode and high-ț dielectric layer would lead to surface roughness between them. The interface layer make the thermal leakage current of the electron bottom injection (voltage= 0~3 V) slightly larger than the leakage of the electron gate injection (voltage= 0~-3 V), which can be observed in Fig. 2. Thus, we only perform the J-V characteristics under reverse bias in Fig. 3.

The examination of device performance with comparable capacitance density at 25 oC

is performed in Fig. 4. We can see the leakage current of TiPrO MIM is significantly

lower than TiO2 MIM and our previous work TiTaO MIM and TiNiO MIM, at a

comparable capacitance density. The lower leakage current of TiPrO MIM is due to the

higher ǻEC between metal and high-NTiPrO interface, higher bandgap of high-NTiPrO

and larger Gibbs free energy of Pr2O3, which reduce the leakage current exponentially.

We also plot ln(J) versus E1/2 relation in Fig. 5. The temperature-dependent leakage

current in MIM is typically governed by Schottky emission (SE) or Frenkel-Poole (FP) as: ¸ ¸ ¹ · ¨ ¨ © § _ v kT V E J b 2 1 exp J [1] 2 1 0 3 ¸¸ ¹ · ¨¨ © § f K e KSH J [2] The K is equal to 1 or 4 for FP or SE case and K_п is the high-frequency dielectric constant (=n2). The refractive index n =2.3 for TixPr1-xO (x~0.67) is reasonable by linear

interpolation of the reported 2.57 for TiO2 and 1.75 for Pr2O3. From Fig. 5a and 5b, the

leakage at 25 oC from Ir top electrode on TiPrO/TaN is ruled by SE at low field and FP at high field by trap-conduction. Besides, the leakage at 125 oC is also dominated by SE at low field and FP at high field. This result would be due to the large 'EC of TiPrO and the larger energy barrier Ib of Ir electrode. The different slopes Jfor the SE and FP cases

arise from the different energy barriers Vb, corresponding tothe work function of the

metal-electrode/dielectric in the SE case or the trap energy level in the dielectric for the

FP case. The fits to the experimental data give slope of 1.56u10-5 or 3.14u10-5 eV

(m/V)1/2 for the SE or FP mechanisms respectively, by using n =2.3 for TiPrO in the

above equations.

Since the conduction mechanism at high electric field for Ir electrode on TiPrO is governed by Frenkel-Poole Emission, we plotted the ln(J/E)-1/KT relation of TiPrO in

Fig. 6a to extract the trapping level. The larger Gibbs free energy of Pr2O3 (+106

kcal/mol) contacted with silicon avoids metal/oxide inter-diffusion. Besides, the binding energy between Praseodymium and Oxygen (928 eV~970 eV) (24) is significantly larger than the binding energy between Nickel and Oxygen (855 eV~861 eV) (25) and that between Tantalum and Oxygen (~530 eV) (26). The both reasons indicate the interfacial trap density of TiPrO (between dielectric and electrode) would be smaller than that of other dielectrics, such as TiTaO and TiNiO. Thus, the trapping level in the TiPrO dielectric will be larger than TiTaO (~0.3 eV) (13) and TiNiO (16). For illustration, we also plot this relation of our previous work TiNiO MIM in Fig. 6b. Compared with Fig. 6a and 6b, the trapping level of TiPrO about 0.43 eV is significantly larger than the

trapping level of TiNiO by about 0.17 eV. This result also explains why TiPrO MIM can

achieve near 2.5 orders of magnitude lower leakage current at -1V at 125 oC than TiNiO

MIM, which is shown in Fig. 6c. In Fig. 7, the SE barrier height (Vb) at 125 oC was

extracted from ln(J/T2)-E1/2 plot. The value for Vb is 1.53 eV for TiPrO device at 125 oC with Ir top electrode.

VCCs are important parameters for MIM capacitor applications, and can be obtained

by fitting the measured data with a second order polynomial equation of C(V) = C(DV2

+EV+1), where C is the zero-biased capacitance, D and Erepresent the quadratic and

linear voltage coefficients of capacitance, respectively. Fig. 8a shows 'C/C-V

characteristics of Ir/TiPrO/TaN capacitors fitted by the above mentioned equation. The lower leakage using high Im (Ir) also improves 'C/C, and VCC Ddue to the trap-related

mechanism (3)-(4), (7)-(8). It should be noted that since linear VCC Ecan be cancelled

by circuit design (27), Dis important for Analog/RF functions and it is strongly

dependent on electric filed and dielectric physical thickness. To the best of our

knowledge, the MIM capacitor with combined higher Im and higher N dielectric is the

only method to achieve lower thermal leakage and better VCC Dsimultaneously without

sacrificing capacitance density in multi-layer or laminate structure. Fig. 8b shows the normalized capacitance versus measured temperature (TCC) of MIM capacitor for capacitance density 16 fF/Pm2 and 20 fF/Pm2, respectively. We can find the TCC showed increase with the increase of the measured temperature (14).

Amorphous dielectrics like TiPrO have some advantages over crystalline materials

including low processing thermal budget, conventional electrode, high uniformity

and scalability to very thin layers, which is suitable for BEOL and manufacture. Table I summarizes important device data for MIM capacitors with various high-N dielectrics and work-function metals. The thermal leakage decreases largely with increasing Im of metal

electrode from TaN to Ir. High 16~20 fF/Pm2 density, reasonable quadratic VCC D of

1702~2174 ppm/V2 and low 7u10-9~ 1.2u10-7 A/cm2 leakage current at 25 oC at-1 V are simultaneously measured in Ir/TiPrO/TaN devices, which are comparable with or better than the best reported data in literature (17). In summary, amorphous dielectric TiPrO shows good thermal stability, leakage current, and scalability to very thin layers issue.

Besides, TiPrO is also the better amorphous dielectric material than TiO2, TiTaO and

TiNiO.

Conclusion

Due to large conduction band offset (~1 eV), large bandgap (3~4 eV), large Gibbs free energy (~106 kcal/mol) of Pr2O3, large binding energy of Pr-O (928 eV~970 eV) and

high dielectric constant (~50) of TiO2, the mixed high-NTiPrO is a potential material

candidate for electronic devices. Dielectric material TiPrO shows its excellent amorphous material properties and gives enough high ț value (ț~26-32). By applying the good properties to our MIM device, the device not only shows apparently lower thermal leakage than other dielectric MIM at comparable capacitance density but also meets the ITRS requirement. Such good device integrity indicates TiPrO dielectric is attractive as a very promising dielectric material for Analog/DRAM applications.

The authors at NCTU thank the National Science Council of Republic of China for their support under contract no. 96-2221-E-009-184

TABLE I. Comparison of important device data for MIM Ir/TiPrO/TaN capacitor with various high-N dielectrics and work-function metals. _@2018 ITRS _HfOTb- 2 (6) Al2O3- HfO2 (9) Nb2O5 (12) TiTaO (13) TiNiO (16) This work Process Temp. (oC) ² 420 420 420 400 400 400 430

Top metal ² Ta TaN Ta Ir

(5.3 eV)

Ni

(5.1 eV) Ir*(5.3 eV) Ir*(5.3 eV) Lower

metal ² TaN TaN Ta TaN TaN TaN TaN

C Density (fF/Pm2) 10 13.3 12.8 17.6 23 17.1 16 20 J (A/cm2) @25 oC ² 1u10-7 (2 V) 8u10-9 (2 V) 7u10-7 (1 V) 8u10-6 (2 V) 2u10-6 (1 V) 2u10-5 (2 V) 7.7u10-6 (1 V) 5.6u10-5 (2 V) 7u10-9 (1 V) 1.1u10-7 (2 V) 1.2u10-7 (1 V) 7.4u10-6 (2 V) J (A/cm2) @125 oC ² 2u10-7 (2 V) 6u10-9 (1 V) 5u10-8 (2 V) 4u10-7 (1 V) 1u10-5 (2 V) ² ² 3.6u10-7 (1 V) 7.2u10-6 (2 V) 5.8u10-7 (1 V) 3.8u10-4 (2 V) J/(C‡V) (fA/[pF‡V])   @2 V 3.1 @2 V 14.5 @1.5 V 870 @1 V 4530 @1 V 3.45 @1 V 45 @1 V References

1. C.-M. Hung, Y.-C. Ho, I.-C. Wu, and K. O, pp. 505-511, IEEE MTT-S Intl.

Microwave Sym. (1998).

2. J. A. Babcock, S. G. Balster, A. Pinto, C. Dirnecker, P. Steinmann, R. Jumpertz, and B. El-Kareh, Electrochem., IEEE Electron Device Lett. , 22, pp. 230-232 (2001).

3. S. B. Chen, J. H. Lai, K. T. Chan, A. Chin, J. C. Hsieh, and J. Liu, , IEEE

Electron Device Lett., 23, pp. 203-205 (2002).

4. C. Zhu, H. Hu, X. Yu, S. J. Kim, A. Chin, M. F. Li, B. J. Cho, and D. L. Kwong, in IEDM Tech. Dig., pp. 879-882 (2003).

5. X. Yu, C. Zhu, H. Hu, A.Chin, M. F. Li, B. J. Cho, D.-L. Kwong, P. D. Foo, and M. B. Yu, IEEE Electron Device Lett., 24, pp. 63-65 (2003).

6. S. J. Kim, B. J. Cho, M.-F. Li, C. Zhu, A. Chin, and D. L. Kwong, in Symp. on

VLSI Tech. Dig., pp. 77-78 (2003).

7. C. H. Huang, M.Y. Yang, A. Chin, C. X. Zhu, M. F. Li, and D. L. Kwong, in

8. M.Y. Yang, C.H. Huang, A. Chin, C. Zhu, B.J. Cho, M.F. Li, and D. L. Kwong,

IEEE Microwave & Wireless Comp. Lett., 13, pp. 431-433 (2003).

9. H. Hu, S. J. Ding, H. F. Lim, C. Zhu, M.F. Li, S.J. Kim, X. F. Yu, J. H. Chen, Y.

F. Yong, B. J. Cho,D.S.H. Chan, S. C. Rustagi, M. B. Yu, C. H. Tung, A. Du, D.

My, P. D. Fu, A. Chin, and D. L. Kwong, in IEDM Tech. Dig., pp. 379-382, (2003).

10. Y. K. Jeong, S. J. Won, D. K. Jwon, M. W. Song, W. H. Kim, O. H. Park ,J. H. Jeong, H. S. Oh, H. K. Kang, and K. P. Suh, in Symp. on VLSI Tech. Dig., pp.222-223 (2004).

11. C. H. Huang, D. S. Yu, A. Chin, W. J. Chen, C. X. Zhu, M.-F. Li, B. J. Cho, and D. L. Kwong, in IEDM Tech. Dig., pp. 319-322, (2003).

12. S. J. Kim, B. J. Cho, M. B. Yu, M.-F. Li, Y.-Z. Xiong, C. Zhu, A. Chin, and D. L. Kwong, in Symp. on VLSI Tech. Dig., pp. 56-57 (2005).

13. K. C. Chiang, Albert Chin, C. H. Lai, W. J. Chen, C. F. Cheng, B. F. Hung, and C. C. Liao, in Symp. on VLSI Tech. Dig., pp. 62-63, (2005).

14. K. C. Chiang, C. C. Huang, Albert Chin, W. J. Chen, S. P. McAlister, H. F. Chiu, J. R. Chen, and C. C. Chi, IEEE Electron Device Lett,., 26, pp. 504-506 (2005). 15. C. H. Cheng, K. C. Chiang, H. C. Pan, C. N. Hsiao, C. P. Chou, Sean P.

Mcaloster, and Albert Chin, Japanese Journal of Applied Physics, 46, No.11, pp.7300-7302 (2007).

16. C. C. Huang, C. H. Cheng, Albert Chin, and C. P. Chou, Electrochem. Solid-State

Lett., 10, 10 (2007)

17. The International Technology Roadmap for Semiconductors: Semicond. Ind. Assoc. (2005).

18. H. J. Osten, E. Bugiel, J. Dabrowski, A. Fissel, T. Guminskaya, J. P. Liu, H. J. Mussig, P. Zaumseil, in IEEE IWGI, Toyko pp. 100-106 (2001).

19. K. J. Hubbard and D. G. Schlom, J. Mater. Res., 11, 2757 (1996).

20. I. Barin and O. Knacke, Thermochemical Properties of Inorganic Substances (Springer-Verlag, Berlin, 1973).

21. I. Barin, O. Knacke, and O. Kubaschewski, Thermochemical Properties of

Inorganic Substances, Supplement (Springer-Verlag, Berlin, 1977).

22. K. C. Chiang, C. C. Huang, Albert Chin, W. J. Chen, H. L. Kao, M. Hong, and J. Kwo, in Symp. on VLSI Tech. Dig., pp.126-127, (2006).

23. K. C. Chiang, C. C. Huang, Albert Chin, G. L. Chen, W. J. Chen, Y. H. Wu, Albert Chin, S. P. McAlister, IEEE Trans. Electron Devices, pp. 2312-2319 (2006).

24. S. Lutkehoff and M. Neumann, Phys. Rev. B, 52, 19 (1995).

25. H. M. Meyer, III, D. M. Hill, J. H. Weaver, K. C. Goretta and U. Balachandran, J. Mater.

Res., 6, No. 2 (1991).

26. E. Atanassova and D. Spassov, Proc. 23rd International Conference on

Microelectronics, 2, pp. 709-712 (2002).

27. K.-S. Tan, S. Kiriake, M. de Wit, J. W. Fattaruso, C.-Y. Tsay, W. E. Matthews, and R. K. Hester, IEEE J. Solid-State Circuits, 25, pp. 1318-1327 (1990).

-2 -1 0 1 2 0 5 10 15 20 25 30 Ir/TiPrO/TaN, Measured at 25oC, 1MHz

430oC O₂ anneal 15min, C=20 fF/um2 400oC O₂ anneal 15min, C=16 fF/um2

Voltage(V) C H ( fF/ um 2 )

Figure 1. C-V characteristics of Ir/TiPrO/TaN capacitors with different annealing

temperaturemeasured at 1 MHz. -3 -2 -1 0 1 2 3 10-10 10-8 10-6 10-4 10-2 100 25o_C 125o_C 400oC O₂ anneal 15 min Ir/TiPrO/TaN C u rrent densi ty (A /c m 2 ) Voltage (V)

Gate injection Bottom injection

C=16fF/Pm2 (a) -3 -2 -1 0 1 2 3 10-7 10-5 10-3 10-1 C=20fF/Pm2 25o C 125o C 430oC O₂ anneal 15 min Ir/TiPrO/TaN C u rrent densi ty (A /c m 2 ) Voltage (V)

Gate injection Bottom injection

(b)

Figure 2. J-V characteristics of Ir/TiPrO/TaN capacitors with different capacitance

0 -1 -2 -3 10-8 10-6 10-4 C=16fF/Pm2 25o_C 50o_C 75o_C 100o_C 125o_C 400oC O₂ anneal Ir/TiPrO/TaN C u rrent densi ty (A /c m 2 ) Voltage (V) Gate injection (a) 0 -1 -2 -3 10-9 10-7 10-5 10-3 10-1 C=20fF/Pm2 25o C 50o C 75o C 100o C 125o C 430oC O₂ anneal Ir/TiPrO/TaN C u rrent densi ty (A /c m 2 ) Voltage (V) Gate injection (b)

Figure 3. J-V characteristics of Ir/TiPrO/TaN capacitors for capacitance density with (a)

16 fF/Pm2 and (b) 20 fF/Pm2 measured from 25 oCto 125 oC, respectively.

-3 -2 -1 0 1 2 3 10-7 10-5 10-3 10-1 101 103 @ Measured at 25oC TiPrO MIM, C# 20fF/Pm2 TiTaO MIM, C# 23fF/Pm2 (13) TiNiO MIM, C# 17fF/Pm2 (16) TiO₂ MIM, C# 21fF/Pm2 (13) C u rrent densi ty (A /c m 2 ) Voltage (V)

Gate Ir injection Bottom TaN injection

Figure 4. The comparisons of J-V for different high-N material capacitors, at comparable capacitance density. The leakage current of TiPrO MIM is significantly lower

0 200 400 600 800 1000 1200 1400 -20 -16 -12 -8 -4 0 4 0 200 400 600 800 1000 1200 1400 -20 -16 -12 -8 -4 Gate injection @125oC Gate injection @25o C Schottky emission Poole-Frenkel emission ln (J ) E1/2(V/cm)1/2 C #20 fF/Pm2 Gate injection @125oC Gate injection @25oC Schottky emission Poole-Frenkel emission ln (J ) E1/2(V/cm)1/2 C #16 fF/Pm2

Figure 5. Plot of ln(J) versus E1/2 under electron injection from top electrode for

Ir/TiPrO/TaN capacitors with capacitance density of 16 fF/Pm2 and

capacitance density of 20 fF/Pm2 is shown in the inserted figure. The SE

emission fitting at low electric field and the FP emission fitting at high electric field are measured at 25 oC and 125 oC, respectively.

28 30 32 34 36 38 -18 -21 -24 -27 -30 -33 -36 TaN TiPrO Trapping level × 0.43eV

Gate injection from Ir (Negative bias)

TaN Ir V_g=2.0V V_g=2.2V V_g=2.4V V_g=2.6V V_g=2.8V V g=3.0V ln (J /E ) 1/KT

Trapping Level of TiPrO# 0.43 eV

(a) 28 30 32 34 36 38 -22 -24 -26 -28 -30 TaN TiNiO Trapping level × 0.17eV

Gate injection from Ir (Negative bias)

TaN Ir V_g=2.0V V_g=2.2V V_g=2.4V V_g=2.6V V_g=2.8V V_g=3.0V ln (J /E ) 1/KT

Trapping Level of TiNiO# 0.17 eV

(b) -3 -2 -1 0 1 2 3 10-8 10-6 10-4 10-2 100 @ Measured at 125oC TiPrO MIM, C# 20fF/Pm2 TiNiO MIM, C# 17fF/Pm2 C u rrent densi ty (A /c m 2 ) Voltage (V)

Gate injection _{Bottom injection}

(c)

Figure 6. The FP conduction fitting at high field for (a) Ir/TiPrO/TaN capacitor and (b)

Ir/TiPrO/TaN capacitor are shown. The leakage current measured at 125 oC for

0 200 400 600 800 20 25 30 35 40 45 50 55 TaN Ir TiPrO ~1.53 eV

Gate injection (Negative Bias) Schottky Emission

Ir/TiPrO/TaN @C=16fF/Pm2

Schottky Emission fitting Gate injection @125oC Barrier Height =1.53 eV E1/2(V/cm)1/2 ln (J /T 2 )

0.0 -0.5 -1.0 -1.5 -2.0 0 3000 6000 9000 12000 15000 D=1720 @ C=16 fF/Pm 2 D=2174 @ C=20 fF/Pm2 Measured at 25 oC, 1 MHz ' C/ C ( p p m ) Voltage (V) Ir/TiPrO/TaN MIM (a) 25 50 75 100 125 0.0 4.0x104 8.0x104 1.2x105 Ir/TiPrO/TaN @ 1 MHz 532 ppm/o C @ C=16 fF/Pm2 758 ppm/o C @ C=20 fF/Pm2 N o m a li z ed capaci ta nce( ppm ) Temperature(oC)

Figure 8. (a)'C/C -V characteristics of Ir/TiPrO/TaN capacitors for different capacitance

density. (b)The temperature-dependent normalized capacitance for Ir/TiPrO/TaN capacitors for different capacitance density.